Transplantation of the Sensitized
Patient
Heidi Schaefer, MD
Associate Professor of Medicine
Vanderbilt University
Case Presentation
• 30-year old male with congential kidney
disease who underwent LDTx from his mother
in 1994
• Kidney failed in 2012 due to biopsy proven
chronic allograft nephropathy
• PRA class I % = 0 and class II % = 25
• Noted to have anti-HLA antibodies (DQ8,
DQA1*03) against his brother
• What are his transplant options?
HLA Class I and II
Inheritance of HLA Haplotypes
• HLA genes highly
polymorphic
• Multiple different
nucleotide sequences
for each gene have
evolved
• Millions of possible
combinations of HLA
types
Kidney Matching
• HLA “typing” identifies the alleles carried by a
person.
• HLA “matching” compares donor alleles to
recipient alleles.
• Degree of HLA matching at the HLA-A, -B, -DR
loci affects the survival of the allograft.
Panel Reactive Antibody (PRA)
• Anti-HLA antibodies are made following exposure
to blood transfusions, pregnancy and previous
tissue transplants.
• Can react with HLA molecules on the endothelia
of a transplanted organ’s blood vessels causing
rejection and damage to the organ.
• Determines if someone is “high immunologic risk
or sensitized”
– PRA >30% is considered “high”
Crossmatch
• Final pretransplant immunologic screening
step.
• Detects donor-directed antibodies in the sera
of a potential transplant recipient.
• A positive crossmatch is a relative
contraindication to transplantation.
Sensitization
• 91,000 patients on waiting list for kidney
transplant
• 17% have had previous transplant
• 36% are sensitized per UNOS database
PRA
Incidence
1-10%
4%
11-50%
10%
51-79%
6%
80-100%
16%
Prevalence of HLA Sensitization in
Kidney Transplant Candidates
Improvement in histocompatibility techniques may account for the increase in
prevalence along with the increased number patients who lost their allografts.
Problems in Sensitized Recipients
• Sensitized recipient may have living donor but
cannot receive transplant due to +CM
• Longer waiting times for deceased donor
• Higher acute and chronic rejection rates
• Lower graft survival
PRA
5-year graft survival
0-9%
72.1%
10-79%
65.6%
PRA >80%
61.8%
UNOS data, based on 1997-2000 transplants
Overview
• Detection of anti-HLA antibodies
• Agents used in desensitization
• Options for the sensitized patient
 Pre-transplant desensitization on the waiting list
 Desensitization protocols with living donors
 Paired-kidney exchange
• Treatment of antibody mediated rejection
Anti-HLA Antibody Detection Techniques for Solid Organ Transplantation
Anti-HLA Antibody
CDC
Techniques
PRA
Solid Phase Assay
ELISA-PRA
HLA Cross-match
CDC Cross-match
T: AHG
B: Amos
Flow Cross-match T
and B cell (IgG)
(With or without
Pronase)
Flow
Cytometer
Flow ScreeningPRA
Luminex Single
AntigenCPRA/DSA
Strength of
antibodies
Strength of T and B cell
Flow Cross-match:
T cutoff: <50 MCS
B cutoff: < 150 MCS are
negative cross-match.
MFI; SFI; MESF
Abbreviations: HLA:human luekocyte antigen; CDC: complement-dependent-cytotoxicity; DSA: donor specific antibody; CPRA:
calculated panel reactive antibody; MFI: mean fluorescence intensity; SFI: standardized fluorescence Intensity; MESF: molecular
equivalent soluble fluorescence; MCS:median channel shift.
Quantitating Antibody: Flow Cytometry and
Luminex Single Antigen Bead Assays
Flow Cytometry Positive Readout:
Median Channel Shift
T cell cross match >50
B cell cross match >150
Negative
Luminex Single Antigen Bead Assay
Readout: Mean Fluorescence Intensity
Class I
Channel
Shift
MFI
Positive
Class II
Overview
• Detection of anti-HLA antibodies
• Agents used in desensitization
• Options for the sensitized patient
 Pre-transplant desensitization on the waiting list
 Desensitization protocols with living donors
 Paired-kidney exchange
• Treatment of antibody mediated rejection
Basic Concepts in Desensitization
• Removal of existing
antibodies
 Plasmapharesis
 Immunoadsorption
• Inhibition of residual
antibody and
complement cascade
 Intravenous
Immunoglobulin (IVIg)
 Eculizumab (C5 inhibitor)
• Depletion of antibody
producing cells
 Naïve and memory B
cells: rituximab
 Plasma cells: bortezomib
• Suppression of the T
cell response
 Induction agents
 Triple
immunosuppression
with CNI, MMF, steroids
Mechanisms of IVIG
Jordan SC et al. Transplantation 2009; 88:1
Eculizumab
• Genetically humanized
monoclonal antibody
• Anti-C5
• Blocks the activation of
terminal complement
• FDA approved for
treatment of PNH
• Primarily used for AMR
• Increased risk of
infections with
encapsulated bacteria
Hillmen et al. NEJM 2006; 355:1233
Rituximab
• Genetically engineered
monoclonal
murine/human
antibody
• Anti-CD20
• FDA approved for
treatment of lymphoma
• Used for desensitization
and AMR
Bortezomib
• Proteasome inhibitor
• Directly targets
antibody production by
plasma cells
• FDA approved for
multiple myeloma
• Primarily used for AMR
• Side effects include
thrombocytopenia and
disabling neuropathy
Richardson et al. NEJM 2003; 348:2609
Overview
• Detection of anti-HLA antibodies
• Agents used in desensitization
• Options for the sensitized patient
 Pre-transplant desensitization on the waiting list
 Desensitization protocols with living donors
 Paired-kidney exchange
• Treatment of antibody mediated rejection
• 35% of IVIG treated patients were transplanted within 2 years as compared to 17%
in placebo group
• Projected mean time to transplantation was 4.8 years in IVIG treated patients and
10.3 years in placebo group
• Mean PRA levels were decreased to 50% from 80% at 4 months
• 20 highly sensitized patients
underwent desensitization with
IVIG and rituximab over 4-week
period
• 16 (80%) received transplant
• 6 deceased donor
• 10 living donor
• Outcomes at 12 months
• Patient survival = 100%
• Graft survival = 94%
• Acute rejection rate = 50%
• AMR = 31%
• 76 highly sensitized patients
underwent desensitization with IVIG
and rituximab over 4-week period
• 45 deceased donor
• 31 living donor
• Deceased donor waiting times
reduced from 96 months to 4 months
• Outcomes at 24 months
• Patient survival = 95%
• Graft survival = 84%
• Acute rejection rate = 37%
• AMR = 29%
• Development of AMR was
significantly associated with strength
of DSA by SFI units
Vanderbilt Experience
• 27 patients
• 15 treated with
rituximab
• Outcomes
• Patient survival = 96%
• Graft survival = 93%
• 10 rejection episodes
• 4 AMR
• Rejection free graft survival
improved with rituximab
therapy
• Received IVIG and plasmapharesis pre/post-transplant
• 5 patients (28%) developed AMR
* PP not viable option for those on waiting list as does not
result in durable reduction in HLA antibody
• 211 highly sensitized
patients who
underwent live donor
transplant
• Treated with PP/low
dose IVIG
• Desensitization with
live donor provided
significant survival
benefit as compared
with waiting for
compatible organ
Comparison of PP vs. High-Dose IVIG
Desensitization
Stegall et al. AJT 2006; 6: 346-351
Overview
• Detection of anti-HLA antibodies
• Agents used in desensitization
• Options for the sensitized patient
 Pre-transplant desensitization on the waiting list
 Desensitization protocols with living donors
 Paired-kidney exchange
• Treatment of antibody mediated rejection
*Antibody mediated rejection significantly associated with development
of transplant glomerulopathy.
Transplant Glomerulopathy
Cosio et al. AJT 2008; 8: 492-496
100%
n=2
100
88%
Graft Loss (%)
75
57%
n=7
47%
50
35%
25
30%
0
n=8
6% 6%
0
I
24%
II
III
Type of AMR
Median SCr = 1.6 mg/dL (0.8-2.7 mg/dL)
TG – transplant glomerulopathy
Patient Actuarial Death- TG
Survival
censored
GRAFT SURVIVAL
No
CMV
Proteinuria
BKV
Pathologic Diagnosis of Rejection
Criteria for Antibody Mediated Rejection
Clinical Outcomes Per Luminex MFI
Values
IVIG only
IVIG only
IVIG/PP____
DSA MFI < 6,000
DSA MFI > 6,000 DSA MFI>6,000
(n=33)
(n=17)
(n=20)
___________________________________________________________________________________
Median F/U (mos)
Patient survival
Graft survival
Living
Deceased-donor
Acute rejection
AMR
ACR
Biopsy proven CAN
Transplant glomerulopathy
Median Cr (mg/dl)
Patients with Cr < 1.4
DSA loss during F/U
30 (4-80)
100%
97%
100%
88%
0%
0%
0%
6%
6%
1.1 (0.6-3.1)
81%
77%
Akalin et al. CJASN 2008; 3: 1160-1167
40 (14-53)
100%
65%
67%
64%
59%
47%
12%
36%
12%
1.2 (1.0-3.1)
73%
31%
16 (12-28)
90%
75%
88%
67%
20%
15%
5%
20%
10%
1.4 (0.8-1.9)
87%
36%
No DSA identified
MFI <5,000 and >0
MFI >5,000 and <10,000
MFI >10,000
Bortezomib Therapy for AMR
• Directly targets
antibody production
by plasma cells
• Side effects:
thrombocytopenia
and peripheral
neuropathy
• Bortezomib alone is
not adequate
therapy for AMR
• Outcomes primarly
in case series
Eculizumab Therapy for AMR
Overview
• Detection of anti-HLA antibodies
• Agents used in desensitization
• Options for the sensitized patient
 Pre-transplant desensitization on the waiting list
 Desensitization protocols with living donors
 Paired-kidney exchange
• Treatment of antibody mediated rejection
Traditional Paired Kidney Exchange
Kidney Transplant Chains
non-directed altruistic donor
R
R
D
R
Cluster #1
D
R
Cluster #2
D
R
D
D
R
Cluster #3
Etc.
D
Paired Kidney Exchange Programs






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Washington Regional Voluntary Living Donor Registry
New England Program for Kidney Exchange (NEPKE)
Ohio Organ Transplantation Consortium
Alliance for Paired Donation
Johns Hopkins Medical Institutions
North Central Donor Exchange Cooperative
National Kidney Registry
UNOS