From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
The
BLOOD
VOL.
58, NO.
The
American
Journal
Society
of
of Hematology
1
JULY
1981
REVIEW
The
Factor
VIII
Complex:
Structure
By Leon
Normal
human
that
are
factor
the
VIII
under
T
contains
in
separate
HE
(von
control,
properties,
and
IMPORTANCE
Willebrand
have
distinct
have
unique
of factor
the
past
interest
decade
in these
VIII
common
properties
hereditary
of factor
evolving
understanding
function.
The
concept
biologic
there
has
diseases,
bleeding
VIII. These
that
factor
functions-coagulant
and
determined,
factor)
are
preliminary
the clinidiseases,
disease.
structure
two
activity
and
factor
was
from
VIII
interact
vivo
with
role
strengthened
human
and
procoagulant
and
distinct
a role
in
platelets
in primary
in a way
and
that
hemostasis.25
the
might
capacity
summarized
in Table
I and
reflect
Subsequent
the
relationship
antibodies
and can be measured
(as VllI:CAg)
these reagents
are used for immunoassays.
The
Vol. 58, No.
1 (July), 1981
now
of
the
Willebrand’s
interaction
remain
to
be
available
permits
a
molecular
defects
in
disease.
component
protein
promotes
cipitated
mass,
interacts
with
platelets
in a way that
primary
hemostasis,
and can be immunopreby heterologous
antisera.
It is usually
desig-
qualitatively
Although
nents
are
is
when
other,
comprises
the
majority
of
the
(VIIIR)
or von
in quantity
or is
abnormal
in von Willebrand’s
disease.
it has been suggested
that the two compoproperties
of a single
macromolecule,6’7
several
kinds of data demonstrate
the essential
differences of the two proteins.
(1) The factor
VIII
procoagulant
protein
and the
factor
Vill-related
protein
are controlled
by different
in von
pattern
an in
studies
illustrated in Fig. I.
One
component
of the factor
VIII
complex
has
antihemophilic
factor
procoagulant
activity
and is now
usually
designated
VlII:C.
It is inactivated
by human
Blood,
von
of their
structures
information
understanding
and
nature
larger
found
to
have suggested
an alternative
interpretation,
and it is
now generally
accepted
that plasma
factor
VIII
is a
complex
of two components
that
have distinct
functions,
biochemical
and immunologic
properties,
and
genetic
control.
The properties
of these
components
are
the
the
biochemical
genes.
Isolated
VlII:C
hemophilia,
a disease
inheritance.
In contrast,
by reports
that
proteins
bovine
plasmas
had both
activity
While
of the
nated factor Vill-related
protein
Willebrand
factor
since it is reduced
primary
hemostasis-was
first suggested
as an explanation
for the dual defect
in von Willebrand’s
disease.’
The logical
inference
that factor
VIII is a bifunctional
molecule
purified
functions.
details
hemophilia
and
in the
have led to an
has
the
essential
been
intense
the
two
most
VIII
VIII
factor)
in hemostasis
disorders,
studies
of factor
and
biochemical
and blood coagulation
is obvious
from
cal problems
in the factor
VIII
deficiency
classic
hemophilia,
and
von
Willebrand’s
During
research
The
and
Function
Hoyer
physiologic
proteins
coagulation.
(antihemophilic
protein
genetic
of two
and
protein
VIll-related
immunologic
a complex
hemostasis
procoagulant
factor
and
plasma
important
W.
and
(2)
The
From
University
Supported
HL
Willebrand’s
is that
tography
buffers
studies,
buffers
16872.
Submitted
Address
Connecticut
(C I 981
deficiency
transmitted
reduced
disease,
of an autosomal
two
is characteristic
by X-chromosomal
or abnormal
VIIIR
proteins
and
the
can
Hematology
of Connecticut
be separated
in part
by
November
reprint
Health
by Grune
Division,
School
inheritance
by chroma-
19, 1980,
Center,
& Stratton,
of
Grants
accepted
February
Farmington,
Inc.
strength
In most
in the
Farmington,
Research
to Leon
0006-4971/81/5801-000l$02.00/0
Department
of Medicine,
USPHS
requests
is
gene.
or centrifugation
in high
ionic
(1 M NaCI
or 0.24
M CaCI2).8”
the inclusion
of protease
inhibitors
does not affect
the separation.’2”3
the
of
W. Hoyer,
Conn.
M.D.,
06032.
Medicine,
Conn.
HL
16626
12,
and
1981.
University
of
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
2
LEON
Table
Vlll:C
1 . The
Components
The factor
of the Factor
VIII procoagulant
protein:
VIII Complex
VIIl:C
philic factor.
as:
Identified
Factor
VIII procoagulant
activity
The procoagulant
property
that
in standard
is measured
(VlIl:C)
of normal
plasma
coagulation
VIII procoagulant
Antigenic
with
VIII:C.
carried
VIIIR
The factor
out with
normal
time
factor.
and bleeding
in vivo.
as:
Identified
Factor-VllI-related
Antigenic
antigen
Ristocetin
cofactor
The property
supports
an VIII:C/VIIIR:Ag
plasma
plasma
by both
independently
ing being
the
von Willebrand’s
(4) The
agglutination
proteins
are
1 ),17
and
have VIIIR:RC
VIII:C.”
the
activ-
VIII
complex
do
vary together
pathologic
situa-
a description
of the
properties
of
of the two
immunoassays,
conditions,
period
proteins,
vary
the most
in patients
the
different
PROCOAGULANT
PROTEIN:
FACTOR
antigenic
Properties
present
time,
mation
about
the
VIII
procoagulant
strikwith
tions,
with
been
deter-
that
there
biochemical
protein,
studies
of VIII:C
the intact
factor
recently
have
VIII
of
Biochemical
concentration
function
and
proteins
of 1 2,600:
can
ANTIHEMOPHILIC
platelets.
under
certain
posttransfusion
disease.’
two
two
is no
protein
retains
absence
of VIIIR
two components
of the factor
however.
Their
concentrations
most
normal,
stressful,
and
VIIIR that
At
(3) The
measured
ratio
protein
ofdetectable
FACTOR
(VIIIR:RC)
of normal
normal
of the
The
procoagulant
in the virtual
there
antibodies.
ristocetin-induced
washed
(i.e.,
but
that are
on VIIIR
by heterologous
independent.
VIII:C
activity
ered in detail
after
the two components.
(VIIIR:Ag)
determinants
detected
plasma,
HOVER
tions,’9
and standard
purification
methods
separate
the intact
(two component)
factor
VIII complex
from
other
plasma
proteins.
This interaction
will be consid-
that is necessary
adhesion
platelet
the von Willebrand
from
levels.’6
properties
also
full
The
interact,
under
antibodies.
protein:
protein
associated
by immunoassays
human
VIII-related
(Vlll:CAg)
closely
Measured
A large polymeric
for
antigen
determinants
VIII:CAg)
in VIIIR:Ag
The biologic
factor-Vill-related
ity in the absence
assays.
Factor
(and
change
(5)
the antihemo-
W.
the
after
published
infor-
properties
of the factor
per se. With
few excep-
function
have
VIII
complex,
factor
characterized
is little
VIII
been carried
out
and it is only
procoagulant
separation
protein
from
has
VIIIR
as
Factor
VIII
procoagulant
activity
is mactivated by human
antibodies
from
multitransfused
hemophiliacs
and patients
with spontaneous
inhibitors;
well as from the other plasma
Bovine
VIII:C
has
been
300,000-fold
from
plasma
ristocetin
ing
time
Although
the G-200
gel filtration
properties
of the
protein
with
VIII:C
activity
suggested
a molecular
weight
of 250,000-300,000,
analysis
in sodium
dodecyl sulfate/urea-polyacrylamide
gel electrophoresis
identified
a triplet
of protein-staining
bands
with
minants.
patients.
noassay
Human
cofactor
activity
(VIIIR:RC)
are
characteristically
and
normal
the bleedin these
Each protein
can be measured
by an immuthat
is independent
of the other
protein.’4”5
anti-VIII:C
coupled
to Sepharose
remove
prjfl5#{149}l72O2
purified
approximately
by Vehar
and
Davie.2#{176}
x-GIRc11L&PE
-
? CELL
Th
VIII:C
VIIIR
-
ENDOTHELIAL CELL
-
MEGAKARYOCYTE
SUBUNIT
/
VIIIR
VIII:C
+
HIGH
POLYMER
IONIC
REDUCTION
STRENGTH
(VIII:C)
(VIIIRPOLYMER)
VI IIRPOLYMER
VIIIR
THE
FACTOR
VIII
COI4LEX
IN
PLASMA
+
Fig. 1 .
The factor
VIII complex.
This
schematic
interpretation
indicates
the interaction
of
the
two
components
and
their
genetic
control.
The
effects
of
SUBUNITS
high ionic
strength
are also noted.
VIII:C
and
reduction
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
THE
FACTOR
3
VIII COMPLEX
molecular
weights
of 85,000,
88,000,
and
electrophoretic
properties
did not change
fled VIlI:C
proteolytic
was reduced
with 2-mercaptoethanol,
cleavage
to smaller
proteins
accomplished
by incubation
factor
Xa, or activated
protein
VIII:C
93,000.
when
had
ies to the VIII:C
activity.
purified
bovine
VllI:C
protein
has
it may be difficult
be
purification
with all standard
of bovine
VIII:C
each
1 25-liter
ma, an overall
A
0
?=
is
methods.
protein
batch of specially
VlII:C
recovery
the
poor
yield
only
from
bovine
estimated
plasto
80
100
Elution
not
to
For example,
was obtained
collected
that was
60
0.0005
h
U/mI
‘4,
120
Volume
(ml)
Thrornbin
A
.20’
U%
>-‘
?
IC
.‘
.10
ID
U
l%.20
We
have
rated
recently
from
VIIIR
completed
and
an immunoadsorbent
not stable
in the
albumin
or similar
other
studies
human
technique.’7
absence
of
proteins
that
of VlII:C
plasma
sepa-
proteins
modified
present
had
during
purification,
during
the procedure,
While
added
this VIII:C
is
bovine
serum
prevent
loss of VIII:C
the
activity,
same
ratio
as
did
prepared.
The
estimated
factor
VIII
of
the
functional
plasma
molecular
procoagulant
protease
and the
inhibitors
purified
to
from
weight
protein
were
VIII:C
Both
proteins
are
highly
asymmetric
proteolysis.
activity
60
80
it
of
human
the
separated
in
molecules
is not
inactivated
100
Elution
0.01 U/mI
cc
t
was
this
that
120
Volume
(ml)
Thrombin
C
.10
C
A
cE
4
I
,
o
0-
-0-
60
,
-0-
-0 ,
-
ti
“a..
a’
80
immunologic
which
is not surprising
since
the
V in prothrombin
activation
is
plays
in factor
X activation.
activated
by thrombin
Factor
VIII procoagulant
0
“o-
100
Elution
manner
is 285,000.21
This value
has been calculated
from the properties
of VIII:C
on Sephadex
G-200
gel
filtration
(Fig. 2A), from which
Stokes’
radius
can be
estimated
by comparison
with standards,
and sucrose
density
gradient
centrifugation
(8.25).
These
properties of unactivated
VIII:C
are similar
to those recently
obtained
for bovine
factor
V by Nesheim
and coworkens.22 The correspondence
cofactor
role of factor
like that which
VIII:C
5
by
from
very
dilute
solutions,
the preparation
can
be
studied
by both
VIII:C
functional
assays
and
VlII:CAg
measurements
to determine
properties
of
VIIt:C
when it is separate
from VIIIR.
Although
it is
difficult
to exclude
the possibility
that the protein
was
are
Vo
.20’
Antibod-
obtain
the necessary
volume
of human
plasma
that has
been collected
in a way that reduces
the likelihood
of
VIII:C
modification
in vitro.
A major
unresolved
in
6
activity
but had no effect
activity
of bovine
plasma.
suggests
that the coagulant
the protein
responsible
for
platelet-aggregating
activity.
Human
factor
VIII
procoagulant
been purified
to homogeneity
and
problem
Control
ci,
protein raised in rabbits inhibited
bovine
VIII:C
procoagulant
on the platelet-aggregating
This observation
strongly
protein
is separate
from
obtained
0.4 mg
A
but
be
could
with
thrombin,
C.2#{176}
The purified
no platelet-aggregating
The
pun-
-a-
‘a
120
Volume
(ml)
Fig. 2.
The Sephadex
G-200
gel filtration
properties
of VIII:C
that
has been
separated
from
VIIIR.
Vlll:C
procoagulant
and
Vlll:CAg
measurements
are indicated.
For reference,
the void
volume
(V0) is noted,
as are the elution
volumes
of lgG (G) and
albumin
(A). (Modified
from Hoyer and Trabold.2’
) (A) VIII:C free of
detectable
VIllA.
(B) Thrombin-activated
Vlll:C.
A part of the
preparation
characterized
in panel
A was incubated
with
5 x
104U/ml
human thrombin
for 4 hr at 37’C prior to gel filtration.
(C) Thrombin-inactivated
VIII:C. A part of the preparation
characterized
in panel A was incubated
with 102U/mI
human thrombin
for 4 hr at 37’C prior to gel filtration.
when
the
intact
factor
VIII
reducing
agents,
e.g.,
This stability
is striking
loss of nistocetin
cofactor
Intact
thiol groups
in VIII:C
function,
inhibitors,
including
complex
is incubated
0.05
M 2-mercaptoethanol.7
when compared
to the
activity
do appear
however,
the specific
in these
with
rapid
experiments.
to have an important
and a variety
of
reagent,
p-chloromer-
role
thiol
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
4
LEON
curibenzoic
procoagulant
calcium
acid,
inactivate
VIII:C.23
activity
is also
affected
concentration.
pH 6.9 and
and above
EDTA
and
cate that
tant.24
VlIl:C
is most
stable
VIII
and
plasma
cation
concentration
is also
avalin-A-agarose
binds
preparations,
and
the
VIIl:C
by the sugar,
limited
success
a-D
VIII:C
procoagulant
it necessary
to express
the plasma
protein
by reference
to standardized
plasma
collected
and stored
in a way
that express
interpretation
activation
values
are
a ratio.
at the
estimate
the
“normal
plasma
They
do not
present
time.
amount
ments
ofthe
the proportion
of protein
level”
of
intact
human
of protein
approximately
50
activity
A
have
One
molecular
of course,
222 ng/ml,
is incorrect
protein
that has been
factor
content
are
stable
than
VIII:C
correlation
any
can,
corresponds
From
to a
measure-
value
for
between
activity
and
determinants
activity,
ofserum
of those
The
in
U/mI
of variation
VIII
procoagulant
(Fig.
3). VIII:CAg
is striking
in the case
values
are 6O9’o-8O%
however,
in which
in the
and
this
the VIII:CAg
corresponding
1.5
(22)
#{149}
C’
content
of this
pools of human
that reduces
the
similar
coefficient
made
1.0
C
.
#{149}
#{149}#{149}
SC
#{149}
:.
I
I,-.
>
can
be
obtained
from
the
specific
activity
of apparently
homogeneous
bovine
VIII:C
(4500
U/mg).2#{176} It must
be recognized,
however,
that
the estimated
plasma
concentration,
VIll:C
includes
plasma
VIII:CAg
more
the
S
has
factor
VIII complex’8’25
and
that is VIlI:C,6
the value
is
ng/U.
and
is ca. l0%.’
there
is excellent
NORMAL
Thus,
all
measures
that
laboratories,
these assays
In general,
separations.’5’2729
is 0.01-0.03
HOVER
is
or loss.
arbitrary
I U/ml.
two-site
solid-phase
of VlIl:CAg
assays
in these
glucopyranoside.’7’2#{176}
of VIll:C
purification
likelihood
of VIlI:C
VIII:C
and VIII:CAg
impor-
bovine
VIll:C
has
for carbohydrate
in both cases
that
residues.
Concon-
purified
phase
and
sensitivity
most
between
7.2, and a marked
loss occurs
below pH 6
pH 8. The
very
low VllI:C
content
of
ion-exchange
resin-treated
plasmas
mdi-
Although
neither
human
nor
been
purified
in sufficient
quantity
analysis,
there
is indirect
evidence
the molecule
contains
carbohydrate
eluted
The
Factor
by pH
W.
if the purified
either
activated
or inactivated.
U
4
t
I’-
t
0
z
.
0.5
U
I
1.0
1.5
4
_a
WILLEBRAND’S
VON
DISEASE
(18)
I
D
a
Immunologic
aaaa
Properties
Human
t
anti-VIlI:C,
obtained
from
multitransfused
hemophilic
patients
that develop
inhibitors
rare individuals
who form autoantibodies
vate
VIIl:C,
do
not
form
detectable
a
assays
for VIII:CAg.’5’2729
VIlI:CAg
immunoassays
man
anti-VIlI:C
of immune
dissolution
obtained
Bethesda
that
complexes
at low
has
followed
pH.
The
from
high-titer
units/ml),
and
any
consistent
difference
spontaneous
anti-VIII:C.
been
obtained
with
two
radiolabeled
purified
than
appear
between
hemophilic
To date, similar
results
assay
hu-
methods:
0.5
0.5
HEMOPHILIA
and
been
1000
to be
and
have
fluid
I
I
1.0
1.5
(97)
o;o;
0
0
&
00
I
o
0
t
0
by preparation
by their separation
antibodies
have
sera
(greater
there
does not
different
I
0
immunoprecipi-
require
been
Ia
and from
that macti-
tates
with
VIII:C
or with
the factor
VIII
complex.
Nevertheless,
these sera can be used to detect
VIII:C
antigen
determinants
by antibody
neutralization
assays26
and
by more
sensitive
immunoradiometric
a
0.5
FACTOR
:C
0
U
t
1.0
ANTIGEN
1.5
(Units/mI)
Fig. 3.
The relationship
of factor
VIII procoagulant
activity
and VIII:CAg
in normal
individuals
and in patients
with hemophilia
and von Willebrand’s
disease.
In the hemophilia
panel,
the large
circle at the origin represents
43 plasma
samples
with no detectable Vlll:C or VIll:CAg.
The large circle with an asterisk
represents
18 plasmas
that
had <0.01
U/mI
VllI:C
and 0.01-0.06
U/mI
Vlll:CAg.
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
THE
FACTOR
plasma,
even
ty.2729
Careful
VIII:C
and
though
loss
concentrations
60% of the
VIlI:CAg
thrombin
bly
there
studies
human
dependent
is no residual
VIII:C
carried
with
out
ct-thrombin
of
VIII:CAg
below
0.1
NIH
concentrations.2’
than
thrombin
but that
effect
qualitative
exposure
procoagulant
thrombin
measured
mediated
with
experiments
proteolytic
detectable
is much
FACTOR
VIll:C,
Biochemical
effect
on
more stable
activity.
Synthesis
VIIIR
most
striking
very
large
properties.39’
property
size.
of
Agarose
a molecular
say
data
there
using
and
protein
is strong
standard
synthesis
suspicion
procoagulant
however,
observations
that
tant role in VIlI:C
production,
VIII:C
values
in severe
and
it will
by immunoas-
studies.
the
liver
Even
plays
be
though
an impor-
the normal
or increased
hepatic
disease
strongly
support
the
concept
that
there
are
extrahepatic
sources
of this protein.
In any case, it is not yet known
what cell type is responsible
for VIII:C
synthesis.
Function
It is generally
coagulation
agreed
by
its
that
VIIl:C
cofactor
role
accelerates
in
the
blood
enzymatic
activation
of factor
X by factor
IXa. In the presence
of
phospholipid
and calcium,
VIII:C
markedly
enhances
this reaction;
in the absence
of factor
IX,, it does not
have any intrinsic
capacity
to activate
factor
X.3436
Native
VIII:C
may not participate
in this reaction,
however,
and VIlI:C
activity
is enhanced
when plasma
or factor
VIII
concentrates
are
incubated
with
dilute
thrombin.37’38
It is likely,
in fact, that thrombin
activation is essential
for VIII:C
activity.36
It has
been
presumed
that
thrombin
activates
VIII:C
by a proteolytic
modification,
and this effect
has
now
thrombin
protein
activated
centrifugation
in contrast
unactivated
been
appears
chains
human
demonstrated.20’2’
Incubation
to cause
a cleavage
in each
of
bovine
VIII:C
VIII:C,2#{176} and
has
gel
filtration
with
of the
thrombinand
ultra-
properties
of a 1 1 6,000-dalton
protein,
to the 285,000
value
calculated
for the
molecule
(Fig. 2B).2’
Factor
VIII proco-
agulant
activity
tions of thrombin-or
is inactivated
by higher
concentramore prolonged
exposure
to the
In all of these
studies,
the
VIII
is its
x 106.41 Although
is not dissociated
factor
filtration
greater
dodecyl
VIIIR
out
not definitive,
to verify
these
consists
of
Willebrand
factor
VIII
gel
studies,
carried
VIII complex
(V I I I R, von
bifunctional
weight
the molecular
weight
obtained
librium
studies
carried
out
are
FACTOR
purified
Despite
many
investigations,
the site of VIII:C
synthesis
is not
known.
Both
transplantation
and
perfusion
studies
strongly
suggest
that
VIII:C
is
released
by the liver under
some conditions.3#{176}33 These
assays,
important
structure.
Properties
reflect
1.12
VIII
thrombinassociated
PROTEIN:
WILLEBRAND
As the bulk of the factor
factor
VI I I-related
protein
factor),
data
obtained
for
suggested
gel filtraprotein
Thus,
are
of VIII:C
VIll-RELATED
VON
systems
and the
not present.
It is
shift is noted
in the
the
(nonfunctional)
modifications
probaon
a further
of
by VIII:CAg
(Fig.
2C).2’
activation
and inactivation
changes
in
to higher
of thrombin
has
a
measure
this
a doseat
they were carried
out in purified
plasma
protein
inhibitors
were
clear
that
VIII:CAg,
enzyme-and
tion
properties
U of thrombin/mI-to
These
the
activipurified
demonstrated
reactivity
original
value-and
determinants
upon
overestimated
since
usual
5
VIII COMPLEX
separations
than
I 06,3940
by sedimentation
in 6 M guanidine
highly
purified
by 6 Mguanidine
human
factor
or 1% sodium
sulfate
(SDS),
subunits
can be detected
is reduced
with
2-mercaptoethanol
or
threitol.
A
acrylamide
single
an
estimated
240,000.
8,39-41
Studies
may be
band
is
detected
gel electrophoresis,
molecular
carried
misleading,
out
on
and
the
weight
and
equiwas
when
dithio-
SDS
poly-
subunits
have
of
195,000-
with highly
purified
factor
however,
for they examine
VIII
only
the small fraction
of the molecules
(ca. 5%-10%)
that
are not lost during
the series of separations.
It is now
apparent
that factor
VIII-related
protein
is, in fact, a
heterogeneous
population
of multimers
that
have
a
range
of molecular
weights
12 x 106. This property
the technique
of crossed
tified
VIIIR
agarose
did
and
the
from
heterogeneity.42
not resolve
the
population
ca.
850,000
to over
first became
apparent
immunoelectrophoresis
Zone
different
of multimers
when
iden-
electrophoresis
in
forms,
however,
was
not
recognized
until
VIIIR
was examined
in agarose
or agarose/
acrylamide
gels in the presence
of sodium
dodecyl
sulfate.7’43
These
studies
of porcine
and human
VIIIR
were carried
out with purified
materials,
and it was
possible
that
the
have been caused
purification.
normal
human
apparent
multimeric
by aggregation
that
Subsequent
plasma
circulates
as a population
that the size distribution
purification
methods,
tion”45
The
plasma
(Fig.
pattern
occurred
analysis
demonstrated
has
of
could
during
unmodified
that VIIIR
of very large multimers
and
is not an artifact
induced
by
freezing,
or calcium
chela-
4).
smallest
polymers
have an apparent
detected
of 0.85
Mr
appear
to be a disulfide-bonded
ca. 200,000
subunit.
The larger
in normal
human
x I 6#{149} This would
tetramer
of the basic
forms have M indicat-
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
6
LEON
W.
HOVER
2.8
x i061.9 x 106-
0.95
x iO6__
1gM
Fig. 4.
The
polymer
pattern
of human
plasma
NJ
VIIR
analyzed
VWD
HEM
by SDS-agarose
VWD
I
electrophoresis.
The
It
migration
of 1gM and 1gM polymers
is indicated
on the left and their molecular
weights
are noted.
The Vlll:R in plasma
samples
was identified
incubation
with tThlIabeled
rabbit anti-VIIIR:Ag
according
to the method
of Hoyer and Shainoff.”
From the left.
normal
individual
and patients
with severe
von Willebrand’s
disease
(VIIIR:Ag
<
0.01 U/mI).
severe
hemophilia.
disease.
and type II von Willebrand’s
disease.
ing
that
they
are
these tetramers,
106, 3.4 x
blood
composed
i.e., they have
etc. (Fig.
4).
106,
clotted
of an
in
glass
tubes
Purified
standard
containing
human
biochemical
5%-6%
at
37#{176}Chas
has
methods.
carbohydrate,
the
as 8 separate
plasmas,
and
of poorly
VIIIR
number
resolved
also
It
free
in these
values
sulfhydryl
factor
been analyzed
by
is a glycoprotein
and hexose,
hexosalso
VIII’8’39’
and
from
This
is approximately
100
of VIII:C
protein.
concentration
Immunologic
assays
greater
than
they
with
been
human
factor
antibodies.
to inactivate
with
antigen.
Laurell
electroimmunoas-
say, counter
immunoelectrophoresis,
and radioimmunoassay
all give similar
results,”4’46’49
and antisera
prepared
in different
laboratories
have had generally
consistent
These
properties
rabbit
in these
antisera
immunochemical
vary
in their
assays.
effect
on human
VIII:C
activity.50
for immunization
The properties
of the material
appear
to be very important
used
in this
regard,
VIII:CAg
on
and
purification
VIII:CAg
the
content
depends
the
method.
Although
small
amounts
of antimay be present
in some sera (in addition
to
the anti-VIIIR:Ag)
they
chemical
measurements.
VIIIR:Ag
with
inactivate
agarose
VIII:C,
removes
the intact
and
both
do not affect
the
The
interaction
factor
VIII
immunoof anti-
complex
anti-VIIIR:Ag
VIIIR
and VIII:C
will also
coupled
from
to
plas-
ma.’6’7
In general,
factor
related
there
is a good
correlation
between
VIII procoagulant
activity
and the factor
antigen
concentration
in normal
human
(Fig.
5).
Parallel
increases
in VIII:C
mas
VIIIR:Ag
have been noted
in plasmas
with
a wide
range
of nonhematologic
normal
individuals
activity
interac-
monospecific
in immunoprecipitin
with
sufficiently
purified
factor
used
to
VIIIR-depleted
A number
detect
and
of
plasma
different
quantify
von
Willebrand
subjected
Factor
Factor-VIII-related
normal
platelet
VIIIR
ristocetin
cofactor
of VIIIR-platelet
VIII,
but
absorption
with
fractions
is often
necessary.
have
purified
immunoprecipitates
plasma
measures
tion.2’47’48 They
are
assays
if prepared
Vill-related
from
immunoprecipitating
vary in their
ability
all form
and they inactivate
as well as other
factor
the
VIIIplasand
from patients
diseases
and
to physiologic
stim-
uli.”
immunized
VIII
form
useful
Although
the sera
assays
times
used
as a
protein
in
5 and 10
Properties
Rabbits
VIII:C,
has been
purified
immunoradiometric
of plasma
in which
purified
VIIIR
was
standard.25
The estimated
values
for VIIIR
normal
human
plasma
have
been between
the
identibeen
studies:
methionine,
tyrosine,
and
are relatively
low and there are no
of VIIIR
protein
in plasma
the specific
activity
of highly
from
sg/ml.
with
groups.39’
The amount
calculated
same
bands
there
is
VIIIR
amine,
and sialic
acid have
been specifically
fled.39’4’ The amino
acid
composition
has
determined
tryptophane
of
M of 1 .7 x 1 06, 2.5 x
Serum
obtained
from
population
of VIIIR.44
As many
can be detected
in most normal
in addition
a population
Mr
of ca. 8-1 2 x 106.
integral
by autoradiography
after
these plasmas
are from a
type I von Willebrand’s
this
designated
“von
Activity
function,
Willebrand
protein
has a central
a property
that
factor”
activity
role
in
been
because
it
has
is deficient
in patients
with von Willebrand’s
disease.’
The
prolonged
bleeding
time
in these
patients
is
presumed
to be due to the reduced
plasma
VIIIR
content
and it is corrected
by transfusion
of VIIIRrich cryoprecipitate.
usually
abnormal
tin-induced
platelet
Two in vitro
in von Willebrand’s
agglutination
platelet
assays
are
disease:
ristoceand
retention
of
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
THE
FACTOR
VIII
COMPLEX
NORMAL
S
(59)
VON WILLEBRAND’S
(5.
DISEASE (23)
(42)
0 HEMOPHILIA
S
>-
S
>
I
#{149}.
#{149}5
S
S
S
S.
.:
#{149}#{149}#{149}:
#{149}.
S
%S
#{149}SS
S
#{149}.#{149}
#{149}
S
#{149}
#{149}
S
0_
D
0.5
0
0
U
000
0
0
6
o
yin-RELATED
in glass
purified
bead
normal
columns.’
factor
Both
VIII
are
is added
and
corrected
to blood
of
a patient
with
severe
von
Willebrand’s
disease.
Although
the way in which
a prolonged
bleeding
time
is a consequence
of the reduced
level of factor
VIII
protein
is not
between
VIIIR:Ag
The
VIIIR
short
yet
known,
this abnormality
and ristocetin
use of
function
period
there
is a good
correlation
and reduced
levels of plasma
cofactor
measurements.5’
ristocetin
has become
of time.
gg
The
for in vitro
assessment
of
widely
adopted
in a rather
initial
0
Q:
b
o
observation-reduced
factor
0
2.5
(Units/mI)
VIll-related
antigen
Ristocetin-induced
critically
examined
plasma
are tested
fixed
concentration
in the
plasmas
satisfactory
as test
refrigerator.
gation
added,
of normal
individuals
and
platelet
aggregation
is more
by assays
in which
dilutions
of
with washed
normal
platelets
and a
of ristocetin.
These
ristocetin
cofactor
assays
can be done
lets or with formaldehyde-fixed
the
0
00
i.O
ANTIGEN
activity
0
0
o
1.5
Fig. 5.
The relationship
of factor
VIII procoagulant
patients
with hemophilia
or von Willebrand’s
disease.
when
o0g00
o’s
FACTOR
platelets
0
0
reagents
The
freshly
platelets
for several
rate
washed
that
weeks
plateremain
if kept
of ristocetin-induced
is related
to the
and the value can
in
aggre-
amount
of plasma
that
is
be obtained
from the aggre-
gometer
tracing
or absent
platelet
aggregation
when
ristocetin
was
added
to platelet-rich
plasma
(PRP)
from
patients
with
von Willebrand’s
disease52-provided
a simple
measure
that
many
laboratories
have
incorporated
into the routine
evaluation
of patients
with bleeding
required
different
by detectable
methods
give
disorders.
Unfortunately,
the assessment
of ristocetininduced
aggregation
in patient
PRP has limitations
as
a diagnostic
technique.
In addition
to its qualitative
nature,
normal
or reduced
aggregation
at one or more
ristocetin
concentrations,
it may be falsely
positive
in
factor
activity
in vivo, as judged
by freedom
from
abnormal
bleeding
and by bleeding
time
measurements,5’
there
are
exceptions.
For
example,
the
VIIIR:RC
value
may become
normal
in von Willebrand’s
disease
some patients
not sufficiently
von Willebrand’s
states,
though
or after
transfusion
the bleeding
time
with primary
platelet
sensitive
to detect
disease.53
While
tion in von Willebrand’s
a plasma
deficiency
and
of normal
presence
deficient
disorders
mild or
abnormal
and it is
moderate
aggrega-
disease
is the consequence
of
can be corrected
by addition
VIIIR,
the phenomenon
also requires
the
of a normal
platelet
surface
protein
that
is
in Bernard-Soulier
syndrome.54
or
with
by
measurement
platelet
similar
of
the
time
agglutination.55
results
under
The
most
conditions.
Although
there
is a good correlation
cofactor
activity
in vitro and presumed
addition,
patients
during
with
pregnancy
with
remains
a variant
and
of ristocetin
von Willebrand
in inflammatory
factor
VIII,
prolonged.56’57
form
of von
even
In
Wille-
brand’s
disease
have long bleeding
times
in spite of
low-normal
ristocetin
cofactor
values
and increased
reactivity
when
ristocetin
is added
to their
plateletrich plasma.45’58
Thus,
the
assays
as in vitro measures
value of ristocetin
of VIIIR
function
cofactor
must not
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
LEON
8
binds
asialoglycoproteins
binds
to the
tive, not the native
or asialo-agalacto-VlIlR.66
obscure
the fact that they do not always
reflect
in vivo
biologic
function.
In this regard,
it should
also be
emphasized
that
VIIIR:Ag
and
ristocetin
cofactor
assays
measure
different
properties
of the
VIIIR
protein.
While
immunoassays
detect
all VIIIR
molecules with specific
antigenic
determinants,
the protein
Synthesis
does not always
have biologic
activity.
Moreover,
artifactually
increased
immunoassay
values
are obtained
capillaries,
and
in megakaryocytes
for the
compared
VIIIR:Ag
smaller
VIIIR
to whole
plasma
electroimmunoassay
cofactor
measurements
polymers
standards
method.
only
when
they
are
by the Laurell
In contrast,
ristocetin
identify
VIIIR
protein
that can interact
with platelets,
and this
limited
to the larger
polymers.59
Thus,
purified
proteins
that lack the larger
VIIIR
will have a very low ratio of VIIIR:RC
to
and, conversely,
material
that is relatively
large
forms
cofactor
will
activity
the whole plasma
Radiolabeled
platelet
discrete
which
have
for
when
VIIIR
capacity
is
plasmas
or
polymers
VIIIR:Ag,
enriched
in
binds
ristocetin
compared
to
specifically
receptor
In fact,
veins
and
cultured
Direct
cells
culture.69
detected
possible
that
protease
have
VIII:C
been
coagulant
media,
might
have
in the
undetectable.7’
and/or
cell
Thus,
either
source
(umbilical
factory
for
VIlI:C
by a different
cell
cause
more
A correla-
THE
INTERACTION
two proteins
tions
indicate
that
noncovalent
bonds
that
to form
(Fig.
drate
of data
suggest
is important
in the
that
presence
VIIIR
factor-VIII-platelet
of
carbohyinterac-
tion
and
in ristocetin-induced
aggregation.
Initial
studies
indicated
that
sialic
acid
removal
reduced
ristocetin-induced
platelet
aggregation
by 65%;64
other
studies
found
no change
in reactivity
even though
the
sialic acid was removed.65
The latter
studies
suggested
that oxidation
of the penultimate
galactose
modified
ristocetin-induced
a 90%
residues
reaction
platelet
aggregation,
and
there
was
reduction
of VIIIR:RC
function
when
these
were
oxidized.
Subsequent
reversal
of the
by galactose
reduction
caused
full
regenera-
disease
states
of either
ty.72 The interaction
intact
when
VIIIR
between
interacts
lectin
that
For
example,
are closely
(nonhemato-
In contrast,
with
factor
there
V activiremains
anti-
bodies
(e.g.,
rabbit
anti-(whole)
factor
VIII)
and
VIII:C
is included
in the immune
complex.
Immunoprecipitates
obtained
with
rabbit
anti-VIIIR
have
coagulant
activity73
and
elicit
anti-VIll:C
when
injected
into
other
rabbits.74
Moreover,
anti-VIIIR
coupled
to agarose
removes
both
VIII:C
from plasma.16”7
IfVIIl:C
and VIIIR
did
one
would
not
immunoadsorbent.
VIIl:C
from
nized
expect
the
anti-VIII:C
the
VIIJ:C
in
the
plasma,
plasma
the value
for
have demon-
activity
are
specifically
human
and
the heterologous
reason
binding
rabbit
with
the
for a loss of
to unrecog-
antiserum,
can
be
can be recovered
from the
in the ionic strength
that
reactions.’7
VIIIR:Ag
unaffected.’6
and VIIIR
not interact,
to remain
An alternative
plasma,
direct
liver with a T’/2 of 5 mm;
is 240 mm.64 Other
studies
liver
observathrough
the components
with heterologous
by the
normal
rabbit
THE
Several
interact
5)#{149}l.14.46.72
Human
antibodies
to factor
effect.
Although
agarose-bound
VIII:C
procoagulant
activity
the
IN
proteins
in most
protein
groups.64’65
residues
are also important
survival.
The asialo-derivative
in VIIIR
is cleared
VIIIR
a complex.
carbohydrate
Carbohydrate
intravascular
that
also
conditions
are unsatisis synthesized
and
two
and
discarded
since the VIII:C
beads
by a modest
increase
does not affect
immunologic
strated
by a
was
COMPLEX
tion
of VllIR:RC
function.
No change
in VIII:C
activity
was noted
when
intact
factor
VIII complexes
were modified
in a way that removed
or oxidized
these
rabbit
VIIIR
not
it is
inactivated
culture
veins)
happen
to copurify.
in plasma
they
is no correlation
ristoceti
n
Several
kinds
tissue
Although
VIll:C
and
VIIIR
have
very
distinct
properties,
it would
be an oversimplification
to suggest
that they have no relationship
and that they are simply
logic)
in the
was
While
VIII:CAg
VIII:C
VIII
only
to platelets
in
activity
however.
or VIIl:C
OF
FACTOR
of the
plasma
bind
obtained
the
cord
synthesis
in the
cord endothesynthesis
by
type.
the concentrations
correlated
in normal
VIIIR
identified
been
media,
tion between
VIIIR
binding
to platelets
and ristocetininduced
platelet
aggregation
has also been
demonstrated.62
VII1R
polymer
heterogeneity
complicates
these analyses,
however,
for it is now recognized
that
large
arterioles,
umbilical
of VIIIR
also
VIII
culture
present
been
human
evidence
has
Factor
in these
identified
of arteries,
throughout
the body, as well as
and platelets.67’68
In addition,
both
VIIIR:RC
medium
from
hal cells.69’70
asialo-deriva-
have
cells
HOVER
to
available
to VIIIR
it has been shown
concentrations
of ristocetin
to bind to the platelets.60’6’
studies
in endothelial
endothelial
and it has been suggested
that
sites
are
present.6#{176} 62 Ristocetin,
to the platelet
membrane,63
appar-
this platelet
its binding.
that increasing
VIIIR
molecules
values
VIIIR:Ag,
standard.
purified
membranes,
receptor
also binds
ently
makes
and enhances
higher
than
Immunofluorescent
VIIIR:Ag
W.
VIII
have a different
antibodies
remove
(and
VIIl:CAg)
from
and
The
ristocetin
difference
antibodies
cofactor
between
in these
the
exper-
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
THE
FACTOR
iments
trations
is likely to be due to the very
of VIII:C
and VIIIR
protein
less than
is VIII:C,
may
9
VIII COMPLEX
1% of the protein
in the factor
the amount
of VIIIR
removed
be so small
in VIIIR
complex
interacts
that
the assays
concentration.
appears
to
with
human
suggestion
be
is found
obtained
normal
by
plasma.
late-eluting
in studies
incubating
Immune
fractions,
relatively
and VIIIR
of reducing
detect
of
a change
soluble
human
complexes
as
well
the
void
volume,
to the void
not present.75
volume
interaction
be inferred
from
on plasma
VIII:C.
concentrations
VIII:C
has
After
tively small protein
on sucrose
agarose
gel filtration,
and
density
ethanol
plasma
is
or 2of a rela-
centrifugation,
precipitation.76
sequence
strongly
suggests
VIIIR
modifies
the properin standard
separation
tech-
niques.
The data
above
summarized
interact
in some
little information
about
is formed.
Nevertheless,
tion
by
high
salt
suggest
way,
but
that
we
the way in which
the susceptibility
buffers
is indirect
very
this complex
to dissociaevidence
complex
formation
inactivation.77
THE
FACTOR
Hemophilia
A
Although
plasma
has
the
low
prevented
hemophilia
(hemophilia
have
studies
begun
have
production
nonfunctional
Two kinds
differentiated
to
of
protects
VIII
define
attempted
normal
protein.
VlII:C
DEFICIENCY
factor
VIII
biochemical
A),
the
that
of immunologic
as this question
concentration
in
studies
in classic
immunologic
VIII
proteo-
DISEASES
molecular
to distinguish
factor
from
techniques
synthesis
of hemophilic
were
with
severe
von
VIII:C
antiserum.
nor
they
did
not
neutralize
studies,
antisera,
the
and
led
others
to the
that nonfunctional
but immunologically
crossmaterial
is present
in all hemophilic
plasIt is now recognized
that
immunochemical
assays
using
heterologous
antisera-whether
immunoprecipitation,
hemagglutination,
intact
normal
from
disease
did
activity.46
These
with
heterologous
inactivat-
Plasmas
Willebrand’s
immunoprecipitates
concept
reactive
mas.’4’46
the
rabbit
VIIIR:Ag,
Thus,
they
factor
VIII
complex
VIIIR:Ag
synthesis
the normal
vitro assays
bleeding
of von
or
done by
radioim-
not antigens
related
do not demonstrate
to
an
in hemophilia
A, only
as one might
expect
from
time and
Willebrand
the normal
values
of in
factor
activity.
It was
distinguishes
hemophilia
measure
from
most
disease,
but they
about
the nature
the
product
forms
of
do not provide
of hemophilia.
of a different
(autosomal)
von
any
They
gene.
Immunologic
study of hemophilia
has become
possible, however,
as human
anti-VIII:C
have been used in
quantitative
immunoradiometric
assays
for VIII:C
antigenic
determinants.’5’27
This technique
has permitted both
qualitative
and quantitative
evaluation
of
VIIIC:Ag
and
a number
of studies
have
been
published
during
identified
VIII:CAg
several
different
patterns
in hemophilic
plasmas
(Fig.
the
There
is no detectable
from patients
with severe
In one-fourth
past
2 yr.’5’2729’8#{176}
They
VIII:CAg
hemophilia
of these
have
of VlII:C
3).
in most
(VIll:C
plasmas
(33
levels-usually
much
as 28%-even
and
plasmas
<1% of
of
I 34)
I%-l0%
of
though
there
is no detectable
VIII:C
coagulant
activity.’5’27
Variable
VIII:CAg
levels are present
in plasmas
of patients
with mild or moderate
hemophilia;
usually
there
is slightly
more
immunoreactive
material
than
VIII:C.
A more extreme
difference
is observed
for the
small
group
of hemophilic
plasmas
that have normal
29,80,81
studies
must
is considered.
be clearly
The initial
antibodies
by the technique
of
identified
“nonfunctional
but
cross-reacting
AHF-like
protein”
in 10%
plasmas.26’78’79
patients
neutralized
of this
there
are low VIII:CAg
normal,
but rarely
as
of
work, done with human
antibody
neutralization,
antigenically
plasmas
properties
normal).
defect.
These
diminished
from
ing
Willebrand’s
information
electrostatic
forces are important.
The biologic
importance
of the plasma
interaction
is also uncertain,
but
VIII:C
instability
in the absence
of VIIIR
(or in
plasmas
that have relatively
reduced
VIIIR)
suggests
that
lytic
immunoassays
subsequently
shown
that VIIIR
purified
from hemophilic
plasmas
cannot
be distinguished
from
normal
VIIIR
by standard
biochemical
methods.’#{176} Thus,
VIIIR:Ag
measurements
can be used as an assay
that
VIII:C
have
quantitative
thereafter,
carried
out with rabbit
antisera
to human
factor
VIII.
These
studies
identified
(by quantitative
immunoprecipitin
measurements)
normal
levels of “factor-VIlIlike protein”
in all hemophilic
plasmas.46
Moreover,
all
munoassay-detect
VIII:C
function.
activity)
is added.
This
that the presence
of intact
ties of the VIIl:C
protein
VIIIR
Shortly
anti-VIII:C
carried
out
While
this change
could be due to a direct
effect of the
reducing
agents
on VIII:C
properties,
they return
to
“normal”
if hemophilic
plasma
(VIIIR
free of VIII:C
and
material
positive
(CRM
+ ), and
to have normal
levels of V I I I :CAg
is very low (2%-lO%
of normal).’5
form
between
the effect
of dithiothreitol
the properties
nated
cross-reacting
they are now known
even though
VIII:C
hemophilic
complexes
anti-VIII:C
with
were detected
in
as at
limited
was
high-affinity
can also
agents
exposed
to low
mercaptoethanol,
cannot
VIII complex
with VIII:C
In addition,
the factor
VIII
“destabilized”
when
VIII:C
antibodies.
The basis
for this
even though
VIII:C
was
fractions
when the antibody
A
VIII:C
different
concenin plasma.
Since
The
plasmas
were
desig-
VIII:CAg
These
even
plasmas
though
are
from
the
the
coagulant
same
activity
patients
is low.
in which
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
LEON
10
CRM+
hemophilia
can
neutralization
assays.26
Thus,
patients
with
be
identified
hemophilia
by
have
ciency
transmitted
by X-chromosome
they
have
normal
VIIIR
synthesis
Nonfunctional
VIII:C-like
molecules
by some
tions
of
hemophilic
immunoreactive
instances.
mutation
ofdetectable
antibody
VIII:C
defi-
inheritance
and
and
function.
are synthesized
patients,
and plasma
concentraprotein
are normal
in rare
in
evolving
understanding
hemophilia
has
(VIII:CAg
and
supplemented
of the
been
based
VIIIR:Ag
standard
molecular
on
measurements)
coagulation
defect
new
that
also improved
our ability
to provide
counseling
for families
affected
by
have
This
has
informed
genetic
this disease.
It is
now widely
recognized
that hemophilia
carrier
detection has been
facilitated
by the combined
measurements
of VIII:C
and VIIIR:Ag,
and most
(>85%)
hemophilia
carriers
can be identified
when
the two
assays
are
done
in
laboratories
that
have
excellent
assay
quality
control
and sufficient
experience
with
reference
populations
of normal
and genetically
obligate
carriers.82’83
Carrier
women
have
normal
VIIIR:Ag
levels;
VIII:C
is reduced
since only half of
their
X-chromosomes
(on the average)
direct
normal
VIII:C
synthesis.
ratio
affect
The
maintenance
of
suggests
that
the physiologic
the factor
VIII complex
act
production,
release,
and
proteins
in a consistent
way.
VlII:CAg
stability
in the
had led to a further
advance
prenatal
noassay
fetoscopy
diagnosis
analysis
at
wk
abnormal
influences
by modifying
metabolism
presence
in genetic
of hemophilia
of fetal
blood
I 8-20
an
of
that
the
the
ofamniotic
counseling,
two
fluid
and
is feasible
by immusamples
obtained
by
of gestation.84’85
concentration.
Qualitative
and
quantitative
VIIIR
defects
have
been
identified
in this
disease;
the
reduced
VIII:C
levels appear
to be secondary.
In its most frequent
form, von Willebrand’s
disease
is a mild or moderate
bleeding
disorder
in which
all of
the
components
of
reduced
in
prolonged.”87
the
quantity
Plasma
factor
and
VIII:C
VIII
the
and
complex
bleeding
VIII:CAg
are
time
may
is
be
VIIIR
polyers
are reduced
in quantity.45
The bleeding
time
prolongation
is variable,
but it is usually
associated
with
reduced
ristocetin
cofactor
activity.5’
While
these
patients
all have
genetic
defects
that
affect
VIIIR,
inconsistent
methods
assays.
HOVER
slightly
higher
than VIIIR:Ag
and VIIIR:RC,
but the
values
are usually
similar
(Figs.
3 and 5). The VIIIR
multimer
pattern
appears
to be normal
since all of the
These
patients
have
an X-chromosome
that modifies
VIII:C
structure.
The absence
VIII:C
protein
in the remaining
patients
may reflect
a structural
defect
that
is so severe
that
antigenic
reactivity
is lost (as well as coagulant
function) or it may indicate
that there
is no protein
in the
plasma.
The
W.
In collabora-
the
and
hemostatic
the results
defect
may
be
of plasma
assays
bleeding
time
measurements
from time to time.88
Severe
von
may
Willebrand’s
vary
disease
unusual)
condition
in which
levels
of both
factor
VIII
quite
and
considerably
is a distinct
individuals
components,
(and
have very low
a markedly
prolonged
bleeding
time, and a major
bleeding
diathesis.
Family
studies
often
demonstrate
that
these
patients
mild,
Although
or
are homozygous
asymptomatic,
VIIIR:Ag
offspring
of parents
with
von
Willebrand’s
disease.
and
VIIIR:RC
less than
1% of normal
disease
(Fig.
5), some
detected
by sensitive
It is not certain
levels
in severe
VIIIR:Ag
are
usually
von Willebrand’s
can
usually
assay methods.89
why VIIl:C
is low
in von
be
Wille-
brand’s
capacity
suggest
tivation,
disease,
for these
patients
have
the genetic
to synthesize
this
protein.
Recent
studies
that normal
VIIIR
protects
VIII:C
from macand
it is possible
that
VIIIR
deficiency
permits
accelerated
VIII:C
inactivation
in vivo.77
It is
also possible
that plasma
VIIIR
levels
may,
in some
poorly
understood
way,
have
an effect
on VIII:C
synthesis
or its release
into the plasma.33
It is likely
that
will
an understanding
of the low baseline
VIII:C
level
clarify
the mechanism
of the delayed
rise and
prolonged
survival
of
VIII:C
(and
VIII:CAg)
after
tive studies
carried
out with Dr. M. J. Mahoney
of the
Department
of Human
Genetics
of Yale
University
School
of Medicine,
immunoradiometric
assay
for
VIII:CAg
(and
VIIIR:Ag
as a control
protein)
has
transfusion
in von Willebrand’s
disease.’
At the present time,
one can simply
suggest
that normal
(transfused)
VIIIR
may stabilize
VIlI:C
or it may directly
excluded-or
accurately
utero for 35 fetuses
tested
influence
Most
von
Willebrands
our
this
case,
autosomal
and
ofvon
hemostatic
locus
that
VIII:C
patients
similar
levels
this has been
biochemical
understanding
the
in
1 , I 980.86
Disease
Immunologic
ified
identified-hemophilia
through
October
disorder
affects
assays
have
Willebrand’s
also
disease.
is transmitted
VIIIR
structure
clarIn
synthesis
or release.
with von Willebrand’s
disease
have
of the different
factor
VIII propertiesdesignated
the “classical”
pattern.
Other
patients
have been found to have nonfunctional
and these
individuals
have normal
or slightly
VIII:C
and
VIIIR:Ag,
very
low VIIIR:RC,
by an
prolonged
bleeding
and
abnormal
on crossed
time.
The
VIIIR:Ag
immunoelectrophoresis,
VIIIR,
reduced
and
a
pattern
and
is
this
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
THE
FACTOR
VIII COMPLEX
11
has suggested
that there
is an abnormal
and nonfunctional
VIIIR.90’9’
It is now apparent
that
the more
rapid
VIIIR
migration
reflects
an increased
propor-
abnormal
tion of small
VIIIR
and an absence
of
multimers
(Fig. 4)#{149}45.92 The shift in multimer
tested
plasma
tion
changes
agarose
according
the
VIIIR
electrophoretic
electrophoresis
to size as
consequence
abnormal
hemostasis
brand’s
disease.
variant
Platelet
large
The
polymer
in the
binding,
disease
has
been
In
is
of von
ristocetin
designated
since
molecules
important
distribution
form
activity,
and bleeding
time correction
large VIIIR
forms and their deficiency
ing diathesis.45’59’92
This
variant
form
brand’s
largest
distribu-
mobility,
separates
well as charge.
of the
impaired
the
by some
investigators
to distinguish
it from the classical
“type
I” pattern
in which
there
is a normal
polymer
pattern
and a similar
reduction
in all components
of the factor
VIII complex.
A distinction
has recently
been made
between
two
subtypes
of type
II von
Willebrand’s
disease
and
the
patterns
contrast,
are
PRP
from
has increased
for ristocetin-induced
VIIIR:RC
is normal
The
all require
the
causes
a bleedof von WilleII”
polymer
patients
platelet
aggregation
and
or minimally
reduced.45’58
with
importance
slightly
patients
with
the
reactivity
when
the
more
common
lIA”
disease
have markedly
reduced
tor activity
and there is no aggregation
is added
to their PRP.
Willecofactor
“type
VIIIR
different.
In addition,
“type
IIB”
disorder
“type
ristocetin
cofacwhen ristocetin
of carbohydrate
groups
in VIIIR
function
has
is, therefore,
been considered
not surprising
in a previous
section.
It
that reduced
VIIIR
carbo-
hydrate
has
Willebrand’s
been identified
disease.
VIIIR
in some patients
with von
subunits
prepared
from
these
when
plasmas
do not have detectable
tested
after SDS-polyacrylamide
resis,
While
and the VIIIR
a carbohydrate
for
some
sialic acid
abnormality
instances
series suggests
content
may
is reduced.93’94
be responsible
of nonfunctional
VIIIR,
another
it is an uncommon
form of von
that
Willebrand’s
carbohydrate
gel electropho-
disease.95
REFERENCES
I. Hoyer
LW:
Stratton,
(976,
BN,
characterization
which
corrects
disease.
Nature
4.
platelet
6.
7.
Invest
8.
globulin
9.
an
Rick
philic
factor
AHF
subunits
I 5.
Molecular
Acad
Sci
240:8-33,
Davie
modification
of bovine
on
human
Elgee
SK:
Exp
Disulfide
bonds
Molecular
cryopreciptate
and
forms
after
of
factor
sorbent
the
19.
Recent
Br
27:502-515,
Hoyer
from
Weiss
LW:
factor
by
Hoyer
LW:
factor:
by salts
V.
salt
Separation
or detergents.
of
1972
Immunologic
VIII).
produced
Hi,
antihemophilic
182:1149-1151,
I 2.
Poon
antihemophilic
Blood48:87-94,
13.
Sussman
MC,
von
factor
(factor
Immunologic
of
Bloom
factor
i Lab
measurement
i Clin
Invest
62:1048-
Factor
VIII
Independent
coagulant
molecular
activentities.
I
1973
Trabold
VIII
coagulant
J Lab
Brockway
NC,
Clin
WI,
and
Collins
activity
Med
Fass
Hoyer
LW:
The
by immunoad-
93:40-53,
DN,
human
IA,
prepared
1979
Bowie
EJW.
Mann
ristocetin-Willebrand
KG:
factor.
I
1977
Physiology
in
of
Blood
factor
VIII,
Coagulation.
in
Poller
Edinburgh,
L
(ed):
Churchill-
1977, pp 141-181
GA,
VIII
21.
factor
Davie
EW:
Preparation
(antihemophilic
and
factor).
Hoyer
LW, Trabold
VIII. Cleavage
ofthe
properties
I Lab
22. Nesheim
of
and
dissociation.
Blood
42:737-747,
254:508-517,
Willebrand
factor:
Dissociation
factor
procoagulant
activity.
24.
Science
OD:
Evidence
VIII)
are
that
linked
functional
subunits
by noncovalent
of
bonds.
Hi:
Dissociation
of
factor
VIII
in the
Clin
ME,
properties
of bovine
Biochemistry
19:401-410,
Austen
VIII.
NC: The effect
or thrombin
on
factor
VIII procoagulant
protein
Med
97:50-64,
Myrmel
characterization
Hibbard
chain
L, Mann
bovine
factor
KG:
Isolation
V. I Biol
Chem
1979
DEG:
Thiol
groups
Br I Haematol
Weiss
1981
KH,
of single
human
during
HI:
V and
A study
VIII
in the
19:447-484,
of the
in plasma.
blood
clotting
action
of
1970
cation-
and
Thromb
pH-dependent
Diath
stability
Haemorrh
14:32-
assay
of factor
51, 1965
25.
VIII
Weiss
TS:
antigen:
EGD,
AL:
Vehar
factor
antihemo-
1976
II,
antigen.
Med89:1278-1294,
of factors
Ratnoff
antihemophilic
Immunoradiometric
Edgington
of porcine
activation.
studies
1973
factor
ID,
Advances
23.
.
of
I980
Antihemophilic
dissociation
I 973
II
Olson
20.
activation.
LW:
chromatography.
J Clin
1970
(AHF,
of factor
Purification
antihaemophilic
thrombin
IS,
VIlI-like
I 7. Tuddenham
properties
and
factor.
studies
procoagulant
138:1015-1020,
Livingston,
5:
Haemorrh
ME,
Med
Isola-
antihemophilic
Willebrand
i, Hoyer
VIII
factor
LabClin
Vill/von
40:316-325,
1972
Zimmerman
18.
Studies
Haemostas
IV. RadioimmunoassayofAHFantigen.
80:822-833,
factor
16.
1975
EW:
Immunologic
VIII).
Lazarchick
the
Nature
structural
CM,
Thromb
1052, 1978
platelets
1976
SL,
Kochwa
18:89-100,
Diath
10.
ME:
inhibitors.
LW:
factor
Med
of
1975
PA:
Owen
WG, Wagner
RH:
active
fragment
following
Thromb
Willebrand’s
factor.
Hoyer
Clin
1978
Hi,
in plasma,
i Haematol
NY
proteolytic
of factor
62:702-708,
von
of human
Heldebrant
240:43-61,
Paskell
structure
Weiss
Ann
57:925-937,
RB,
in
VIII)
1972
Switzer
Mi,
McKee
Invest
of proteolytic
I 978
ity and
VIII.
Sci
ME,
Counts
presence
(AHF,
A (factor
antihaemophilic
JC,
and
Acad
J Clin
quaternary
&
Immunological
factor
Aggregation
bovine
Weinstein
structure
NY
Switzer
factor.
(ed):
Grune
1973
factor
subunit
VIII. Ann
TH
York,
et al:
retention
CRM:
Andersen
ME,
ii,
236:104-106,
and
studiesofhuman
tion,
Biol)
Prentice
PA,
Legaz
Sixma
abnormal
241:149-150,
McKee
5.
Spaet
14.
Y,
anti-haemophilic
porcine
Biol)
in
vol 3. New
of purified
CD,
purified
(New
disease.
Thrombosis.
Wiegerinck
(New
Forbes
by
and
pp 23 1-287
2. Bouma
3.
Willebrand’s
von
in Hemostasis
Progress
26.
Counts
protein.
Hoyer
RB:
Bri
LW,
Solid
phase
Haematol
Breckenridge
immunoradiometric
31:429-436,
RT:
1975
Immunologic
studies
of anti-
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
12
LEON
hemophilic
factor
genetic
variant
27.
Peake
IR,
noradiometric
factor
Bloom
assay
haemophilia,
Bri
(AHF,
von
AL,
Holmberg
ST.
van
on
antigen:
immu-
Results
and
in
Chim
Zukoski
GD:
Plasma
by canine
organ
von
Willebrand’s
cies
of antihemophilic
IM:
Measurement
a solid
dent
1979
Bertina
assay
ofprocoagulant
Acta
107:1
1-19,
Hutchin
factor
RM,
VIII
JP,
VIII
CA
coagulant
adult
rat
32.
synthesis
Am
BrI
procoagulant
factor
41:585-596,
factor
VIII
and
control
J Physiol
as
220:1
factor
isolated
The
VIII
X
and
SI:
by
MB,
of
SI,
role
purification
VIII.
Blood
and
X
1970
of
Thromb
Res
Biol Chem
ME,
SB:
The
by
57.
5, Chong
with
Forma-
reference
human
Studies
factor
on
VIII.
the
J
IC,
and
Pizzo
SV,
hemophilic
McKee
factor
PA:
VIII.
I
G, Counts
human
factor
USA
VIII
Davie
EW:
Isolation
(antihemophilic
Edgington
molecular
forms
72:5121-5125,
Knutson
of
multimers.
Hoyer
Shainoff
EJW:
I
Lab
Porcine
Willebrand
Med
91:307-320,
Clin
circulates
in
multimers.
Blood
45.
normal
Ruggeri
disease.
composition
55:1056-1059,
ZM,
Characterization
of
human
factor
IR:
plasma
VIll/von
as
high
molecular
VIlI/von
weight
on
tool
Diath
in
the
Haemorrh
Ristocetin:
into
Hardisty
A means
two
RM:
aspect
Wagner
RI-I,
assay
of
groups.
of
Blood
Hereditary
giant
of platelet
function.
Brinkhous
and
Pareti
von
factor
I Med
binding
Sixma
sites
and
subtype
ii,
Over
II.
in the
of von
Wille-
I,
Beeser-Visser
Characterization
presence
of
of ristocetin.
P: Demonstration
for
I Clin
Gralnick
Willebrand
N,
platelets
1978
binding
platelets.
Ciavarella
1980
VIII.
to platelets
McKee
DK,
bleeding
PM,
in a new
factor
SV,
Morisato
to
between
302:1047-1051,
MHM,
on human
Proc
disease.
factor
Mannucci
interaction
of human
specific
Nature
inhibitor.
Willebrand’s
Willebrand
Fl,
Willebrand
N Engl
VIII
KM:
a specific
1974
Heightened
Doucet-deBruine
factor
factor
Invest
HR:
and
Willebrand
63:656-664,
Selective
protein
to
character-
VIlI/von
1979
binding
human
of the
factor
platelets.
Blood
1980
Kao
K-i,
Pizzo
VIlI/von
SV,
Acad
Coller
platelet
McKee
Willebrand
occupancy
Natl
Invest
factor
and
Sci
76:5317-5320,
effects
electrophoretic
receptors
Functional
ristocetin-induced
USA
BS: The
P: Platelet
protein:
platelet
for
human
correlation
of
aggregation.
1979
of ristocetin
mobility.
and
J Clin
von Willebrand
Invest
61:1
factor
168-1
175,
I977
TS:
subtypes
Variant
von
by analysis
Willebrand
platelets.I Clin Invest 65:1318-1325,
ZM,
TS:
VIlI/von
63.
BG:
of a new
29 1 :420,
of
protein
new
Thromb
RA,
Relation
ization
1980
Zimmerman
of two
Factor-VIlI-related
to
J Clin
1974
Pizzo
Proc
LW,
Hi:
I Med
Ruggeri
receptor
J:
Relationship
71:2937-2941,
1974
Saito
H: Bleeding
in von
92:96-107,
factor
Rogers
Willebrand’s
content.
Ristocetin-A
Firkin
A new
290:1089,
Weiss
55:9-15,
aggregation.
disease
RD,
factor:
K-i,
62.
Bowie
Willebrand
Med
Proc
A,
in von
antigen
human
1973
Varma
deficient
to
with
1973
Stratton
Kao
1975
GI,
A population
plasma.
KE,
Clin
Factor-VIlI-
in human
I 2:586-588,
Sarji
60.
factor
antibodies
29:652-660,
FR,
and
RI,
Hutton
I Lab
J
of
immunization
platelet
A disorder
Clin
factor).
TS:
MA,
Heterogeneity
61.
J,
Sawers
Willebrand’s
of factor
and
TS:
(factor
immunoelectro-
specificity
after
BG:
MA,
forms
1973
Roberts
Multiple
RB,
The
aggregation.
The
I978
44.
59.
Edgington
1975
activity
von
brand’sdisease.
Clin
Br J
antigen
quantitative
factor,
for
L,
disease
Rickles
Firkin
syndrome:
Zimmerman
factor
HR:
depen-
1973
N Engl
58.
to
1971
Gralnick
of
MNY:
special
1973
rate
Willebrand.
Dickson
Haemorrh
LW,
platelet
Howard
N EngI J Med
prothrombinase
Diath
of a plasma
NatI Acad Sci USA
56. Ratnoff
OD,
impor-
proaccelerin
intrinsic
21 :643,
NR,
normal
TS,
DN,
and
of von
NH:
Schmer
of
Sci
Ames
activity,
248:3946-3955,
Fass
Mi,
55.
1973
Zimmerman
Acad
of
1978
globulin
of
presence
54.
Br Med
X by factors
the
52:928-940,
SI, Schiffman
Andersen
of
antigen:
in
41:687-690,
platelet
1972
GA,
characterization
1X0
1971
Howard
differentiating
activation
CR:
rabbit
MA,
26:363-369,
53.
J
1973
Howard
of
time.
characterization
structure
factor:
factor
Rizza
procoagulant
investigation
by antibod-
an
on collagenous
VIII/von
by
in the
is necessary
VIII
52.
1963
Shulman
Invest 52:2198-2210,
related
intrinsic
of factor
factor
Br I Haematol
SL,
Legaz
that
factor
D: Shear
aggregation
LW,
plasma
Hoyer
assay
disease,
other
and
factor.
An experimen-
Meyer
and
86:152-159,
Thromb
Quantitative
Haematol
activator
substrates.
generation
factor-X-activator
Shapiro
43.
Clin
I 9:1854-1861,
5, Patch
21:221-235,
Invest 51:2151-2161,
NatI
and
Blomb#{228}ck B: The
for
in the
of thrombin.
subunit
of
Biochem
assay
Schiffman
thrombin
Marchesi
42.
of
Br I Haematol
VIII.
Y: Activation
#{216}sterud B, Rapaport
41.
liver.
of formed
of antihemophilic
of intrinsic
PBA,
HI,
Mi:
243:293-294,
Willebrand’s
in
Med
cryoprecipitate.
and
Synthesis
antigen
rat
synthetic
Nemerson
factor
Blood
40.
AL:
related
Synthesis
IX.
using
a specific
Rapaport
39.
livers
1977
VIII;
activity.
the
pig
von
produced
51. Weiss
Bloom
of factor
function
to factor
of activation
38.
biosynthesis
of the
and
thrombin-activated
tion
lR,
VIII
Rapaport
evaluated
Hultin
traces
neonatal
1979
perfused
I-I, Blomb#{228}ck M,
10:267-281,
37.
Peake
VIII,
B,
Suomela
tance
IC,
by the
Inhibition
ies to factor
1X0
perfused
43:307-315,
V)
Nature
factor
Hoyer
the
antigen)
Kernoff
TB,
adhesion
TS,
of
VIII
(factor
1980
I LabClin
factor
of factor
and
deficien-
antihemophilic
M, Larriev
of human
Zimmerman
52:2708-2716,
AL:
Osterud
36.
Generation
1979
activator.
factor
DN:
Immunologic
deficiency)
combined
proaccelerin
disease.
of platelet
VIlI-related
on
against
Tschopp
44:127-139,
phoresis.
147-
and
C, Dreyfus
HR,
Determination
Mandel
observations
Willebrand’s
by antibodies
49.
RL,
AE:
VIII
HOVER
1971
D, Jenkins
inhibition
Haematol
1979
Bloom
35.
Fass
by isolated,
l-Iaematol
factors
8:53-77,
EJW,
E, Giddings
coagulation
34.
Bowie
activity
livers.
Shaw
33.
Jr.
with
factor
Baumgartner
Powell
(factor
anticoagulant
for von
surfaces
1980
P. Reddick
transplantation.
Terweil
OD,
hemophilia
disease,
Meyer
48.
non-haemophilic
NH,
CF.
47.
50.
Owen
Ratnoff
classic
circulating
tal model
phase
1154, 1971
31.
TS,
of
acquired
serum.
with
homologous
23:17-24,
Tilburg
Clin
WP,
Penick
revealed
An
plasma
R, Nilsson
Immunoradiometric
Webster
fetal
Zimmerman
differentiation
CA:
(VIII:CAg)
based
I Haematol
HP,
(VlII:CAg).
30.
VIII
and
46.
in a
Clin Invest 50:244-254,
A antigen
method
Scand
antigen
Ludlam
factor
L, Ljung
factor
II:
JC,
disease
L, Burge
Muller
Veltkamp
Giddings
material
1 , 1968
1979
immunoradiometric
29.
32:962-97
for procoagulant
of antihemophilic
antibodies.
Cross-reacting
A. Blood
Willebrand’s
Haematol42:269-281,
28.
VIII):
of hemophilia
W.
1980
factor
Willebrand
64.
of multimeric
in
plasma
function
and
factor
65.
Sodetz
and
protein.
Gralnick
JM,
Pizzo
in vivo
I Biol
HR:
SV,
McKee
P: Relationship
survival
of human
Chem
252:5538-5546,
Factor
VIII/von
factor
Vill/von
ofsialic
acid
Willebrand
1977
Willebrand
factor
protein:
to
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
THE
FACTOR
VIII COMPLEX
Galactose,
a cryptic
Clin
62:496-499,
Invest
66.
Sodetz
human
factor
by
II,
of von
Willebrand
factor
activity.
I
1978
Paulson
IC,
Pizzo
SV,
Willebrand
of specific
et
factor:
galactose
LW,
de
los
antigen.
Localization
microscopy.
J Clin
68.
Bloom
vascular
AL,
intima:
Nature
al:
Carbohydrate
Impairment
residues.
I Biol
IC,
82.
253:7202-
JR:
Antihemophilic
83.
by immunofluores-
man
1973
laffe
brand
71.
Ci:
Factor
VIII
in haemostasis
and
on
the
RL:
cultured
Synthesis
human
of
endothelial
Haematol
by cultured
anti-
Rizza
Haematol
I
agarose
gels.
74.
Hoyer
nologic
Rhymes
IL,
carriers
of
LW:
A
DEG,
method
with
Synthesis
Br
PBA,
Aroni
study.
Br
detecting
factor
VIII
factor
VIlI-related
1975
antibodies
factor.
in immu-
Nature
(New
I-Ioyer
by human
LW:
The
antibodies
properties
to factor
of
VIII.
Biol)
Invest
effect
Weiss
of reducing
Hi,
in plasma
agents
Res
on factor
VIII
and
Blomb#{228}ck
other
II,
von
Hoyer
Willebrand
LW:
Stabilization
I Clin
of
Invest
78.
Haematol
79.
philia
KWE,
Biggs
of haemophilia
17:163-171,
Feinstein
A:
D, Chong
HM,
Haddon
A
ME,
-
):
Borrett
A study
R,
91.
Kasper
detectable
Price
by
CK,
a
Rapaport
factor
VIII
SI:
K:
disease
Br I
94.
Hemo-
WA,
factor
Blatt
PM,
Serial
Barrow
ES,
Graham
JB:
I
1971
LW,
Zimmer-
detection
Med
I,
of the
296:959-962,
Forget
Merkatz
BG,
IR,
N EngI
Furlong
of
Int.
3-7,
RA,
AL:
Dual
fetal
Hobbins
Mahoney
I Med
Bains
MI:
300:937-
L, Peake
diagnosis
factor
2:994-997,
IR,
of prenatal
VIIIC
and
VIIIC
1980
Mi:
Prenatal
Congress.
World
diagnosis
Fed.
of
classic
Hemophilia,
San
1981
The
von
CF.
Suzuki
studies
in
“variants.”
Blood
Zimmerman
Willebrand
syndrome.
Z.
Harrison
von
Semin
Hematol
K, Zimmer-
disease:
Variability
1980
Abildgaard
severe
I, iefcoat
Willebrand’s
56:712-716,
TS.
in
CF.
von
Willebrand’s
Gruson
R, Rizza
Meyer
D: The
disease.
factor
N
VIII
EngI
I
Med
1979
Kernoff
PBA,
antigen.
Br I Haematol
Peake
IR,
Bloom
VIll-related
CR:
A variant
26:435-440,
AL.
protein
Meyer
D, Obert
Giddings
in von
B, Pietu
structure
of factor
VIII
1974
IC:
Inherited
Willebrand’s
variants
of
N
I
disease.
variants.
Gralnick
I Lab
HR,
VIII/von
Science
VIlI/von
Med
BS:
Willebrand
HR,
VIlI/von
Clin
Coller
EngI
I 92:56-59,
and
Y, Coller
quantiative
IM,
Zimmerman
IS:
Willebrand
factor
in Von
95:590-602,
1980
Carbohydrate
factor
Sultan
qualitative
Zimmerman
G, Lavergne
of factor
disease.
Gralnick
296:1024-1030,
95.
antibody.
1969
50:255-258,
Med 291:1 13-1 17, 1974
Combined
MNY,
CH,
Mahoney
XIV
July
301:1307-1310,
93.
Cobb
of 48 cases.
WA,
Bloom
Lancet
AL:
Willebrand’s
factor
60:390-
1969
Polymorphism
Reisner
R,
(A + and
Science 163:1071-1072,
80.
versus
factor
Denson
types
for
1980
Multimeric
factor.
of
assay
for the
EngI
Lazarchick
measurement
Abildgaard
TS:
92.
coagula-
12:1 177-1 194, 1978
Sussman
by the
Wikstr#{246}m L,
404, 1977
Two
Bloom
factor
G,
R,
Rica,
17:215-227,
related
1977
B, Savidge
Detection
Hoyer
study
haemophilia.
Rodeck
LW,
abnormality
immune
I Clin
Invest
BN,
N
Muir
RS,
Proc.
Costa
89.
of precipitating
AS:
immunologic
I Clin
Bouma
LW.
FA,
Gorer
by
Hoyer
90.
I,
1K,
hemophilia.
man
in
Hoyer
(VIIICAg).
87.
J
antigen
an
hemophilia.
of classic
Mibashan
86.
I
Kernoff
Littell
94l, 1979
haemophilia
and
cells.
a “blind”
for
31:5-12,
Blomb#{228}ck B, Hessel
77.
LW:
endothelial
VIII).
A comparison
studies
OD,
A cooperative
Pilick
diagnosis
88.
CR:
Specificity
tion factors. Throm
VIII
Austen
of antihaemophilic
formed
M: The
Acad
1973
60:1070-1079,
76.
J, Hoyer
human
haemophilia:
associated
Lazarchick
complexes
NatI
SI,
LP,
Thumpston
Wille-
1975
Rizza
identification
75.
Proc
Unpublished
LM,
classic
Firshein
Jose,
Br I Haematol
245:49-51,
cells.
DL:
of
plasma:
19, 1980
using
(factor
Aledort
DeMets
antigen
bycultured
30:447-456,
activity
ofvon
1981
of
P.
Synthesis
enodthelial
Lazarchick
VIII
CR,
Bird
RL:
55:
Ratnoff
hemophilia
factor
Clyne
85.
Nachman
human
47:617-626,
clotting
HG,
Prenatal
1974
EGD,
factor
Detection
73.
LW,
71:1906-1909,
of
72.
Klein
state
84.
cells.
Shapiro
TS,
classic
TS,
in hemophilic
56:6 1 5-6
I977
thrombosis.
IC,
Nachman
by
Hoyer
Tuddenham
release
SA:
EA,
factor
Sci USA
LW,
of
carrier
1973
LW,
antigen
antigen
Blood
Zimmerman
carriers
Clin Invest 52:2757-2764, 1973
70.
coagulant
8 1 . Hoyer
on
of function
Chem
cells
Wilks
importance
Hoyer
factor
Hoyer
52:2737-2744,
241:217-219,
EA,
hemophilic
R,
in endothelial
Giddings
Biol)
Jaffe
Santos
Invest
Possible
(New
69.
VIII
antihemophilic
Hoyer
factor
Factor
of five alloantibodies.
1978
67.
cent
determinant
VIlI/von
removal
7206,
13
deficiency
protein
in
von
of
the
Willebrand’s
1976
BS: von
Willebrand’s
abnormalities.
disease.
N EngI
I Med
1977
IS,
Willebrand
Clin lnvest64:l298-1302,
Voss
R, Edgington
factor
1979
in von
IS:
Carbohydrate
Willebrand’s
of the
disease.
I
From www.bloodjournal.org by guest on March 1, 2016. For personal use only.
1981 58: 1-13
The factor VIII complex: structure and function
LW Hoyer
Updated information and services can be found at:
http://www.bloodjournal.org/content/58/1/1.full.html
Articles on similar topics can be found in the following Blood collections
Information about reproducing this article in parts or in its entirety may be found online at:
http://www.bloodjournal.org/site/misc/rights.xhtml#repub_requests
Information about ordering reprints may be found online at:
http://www.bloodjournal.org/site/misc/rights.xhtml#reprints
Information about subscriptions and ASH membership may be found online at:
http://www.bloodjournal.org/site/subscriptions/index.xhtml
Blood (print ISSN 0006-4971, online ISSN 1528-0020), is published weekly by the American Society of
Hematology, 2021 L St, NW, Suite 900, Washington DC 20036.
Copyright 2011 by The American Society of Hematology; all rights reserved.