Characteristics of antibodies directed against the MNS blood group system
Meenu Bajpai, Himani Aneja, Ashish Maheshwari, Pankaj Jain
Department of Transfusion Medicine, Institute of Liver & Biliary Sciences, New Delhi, India
Introduction
(i)
MNS blood group system (50 antigens currently included) is
Antibody
Identified
Donors
(40)
ANTI-M
33 (82.5%)
Patients
(76)
Total
(116)
Donors
(72358)
Anti-M in patients
This study
{n=74, Patients}
D. BASU et al.
(2013), {n=11,
Patients}
A. JAIN, et al
(2017),
{n=51, Patients}
0.160%
Anti-M Frequency
74/25014 (0.16%)
NA
51/101364(0.05%)
IgG class of antiM antibody
47/74 (63.5%)
5/11 (45.5%)
NA
IgM class of antiM antibody
29/74 (32.4%)
1/8 (12.5%)
11/12 (91.7%)
Anti-M with both
IgG and IgM
component
11/74 (14.86%)
7/8 (87.5%)
1/12 (8.3%)
Transfusion
History
47 (61.8%)
1/11 (9.1%)
21/51 (41.2%)
Obstetric History
17(22.4%)
NA
NA
Patients
(25014)
All blood donors- both voluntary and replacement
41(53.9%)
74 (63.8%)
0.046%
underwent blood donation.
second to the ABO blood group system in importance, and Rh
system in antigenicity.
Characteristics of MNS Antibodies
Frequencies of MNS Antibodies
Study Participants :
(ii)
ANTI-N
4 (10%)
6 (7.9%)
10 (8.6%)
0.005%
0.024%
All patients requiring transfusion of any blood product in
ANTI-S
0
26 (34.2%)
26 (22.4%)
0
0.104%
our centre.
ANTI-s (small)
0
1 (1.3%)
1 (0.9%)
0
0.004%
Anti-M & Anti-S
2 (5%)
1 (1.3%)
3 (2.6%)
0.003%
0.004%
Anti-N & Anti-S
1 (2.5%)
0
1 (0.9%)
0.001%
0
0
1 (1.3%)
1 (0.9%)
0
0.004%
There are five important antigens being M, N, S, s, and U in this
system which are single pass transmembrane proteins on the
(iii)
surface of RBC and are derived from glycophorin genes GYPA
All cases with incomplete data or inconclusive results
were excluded.
Anti-N &
Anti-s (small)
and GYPB on chromosome 4.
Purpose of the present study is to analyze the characteristics of
antibodies to MNS system which have been detected on routine
immunohematology workup and thereby help in advancing the
knowledge of MNS blood group system and red cell typing.
Materials & Methods
Aim: To study serological characteristics of MNSs blood group
Results
Summary and Conclusions

Total donors tested 2015-2022: 72358

Donors included in the study, n=40.

Total patients tested 2015-2022: 25014

Patients MNS system antibodies : 76

Total IH cases identified: 625
M+N- (38.6%), and M+N+ (36.9%), hence it is a challenge to
AUTHOR
of
these
antibodies
with
history
YEAR
STUDY
POPULATIO
N
SAMPL
E SIZE
FINDINGS
116
Anti-M: 63.8%;
Anti-N: 8.6%
Anti S (big): 22.4%
Anti-s (small: 0.9%
652
Anti-M: 14.3%;
71% cases- mixed IgG +
IgM class
708
Anti-M: 2.4%;
Anti-N: 0.3%
Anti S (big): 0.9%
Anti-s (small: 1.3%

Cases with MNS system antibodies: 116

No history of sensitization was present in Donors
Present Study
Wang et.al.
2022,Ann
Transl Med
Changsha,
China;
(patients)
Promwong
et.al.
2013, Asian
J Transf Sci
Southern
Thai
(patients
and
donors)
of
transfusion/transplant/obstetric events.
Study population- 116 participants (Patients & donor) serum
PRESENTATION OF ANTIBODIES TO MNS SYSTEM:
group discrepancy from January 2015- September 2022.
Donor, n=40
Patient, n=76
Study design- This is a retrospective observational study. The
Positive ICT test
39 (97.5%)
74 (97.4%)
medical and immunohematology workup records were retrieved
ABO discrepancy
5 (12.5%)
9 (11.6%)
from the archives after ethical committee approval.
Positive auto-control test
5 (12.5%)
34 (44.7%)
Ferdowsi
et.al.
Stetson et.al.
2022,
Hematol
transfuse
cell ther
2017, Am J
Perinatol
Rep
Tehran,
Iran
(patients)
Ohio, USA
(pregnant
patients)
characterisation of MNS system antibodies.
Antibodies to MNS blood group system are common among
patients, and a majority of these antibodies are clinically
significant.
Detecting antibodies to MNS system is also important for donors
as most antibodies are clinically significant (IgG or IgG + IgM).
showing indirect and/or direct Coombs test positivity or blood
PRESENTATION OF ANTIBODIES
provide antigen-negative blood to patients.
Limited large-scale Indian literature is available for the serological
North
West, India
(patients
and
donors)
antibodies in patients & donors in a single center and to correlate
presence
Various studies have shown a high prevalence of MNS antigens,
Global presentation of MNS Antibodies
3
748
Anti-Mnaturally
occurring antibody; IgM
or IgG.
Causes discrepancy in
blood grouping
Clinically significant at
37◦C.
Anti-M antibodies were
identified in 146 women
and 195 pregnancies
The presence can be detected as a positive ICT test or a blood
group discrepancy, hence these should be routinely used in
patient care, further to provide antigen-negative red cells as a
standard transfusion practice.
References
Jain A, Singh L, Kaur A, Sharma RR. Spectrum of clinically
significant anti-M antibody in patients requiring transfusion. Int J
Blood Transfus Immunohematol 2022;12
GH. Lopez, CA. Hyland, RL Flower. Glycophorins and the MNS blood
group system: a narrative review. Ann Blood 2021; 6: 39.