A total of 30 blood group systems are recognized by the International Society of Blood Transfusion (ISBT). Nine blood group systems (ABO, Rhesus, Kell, Kidd, Duffy, MNS, P, Lewis, and Lutheran) are considered to be clinically significant as these are known to cause hemolytic transfusion reactions (HTR) and hemolytic disease of fetus and newborn (HDFN) [
In developing countries like India only ABO and D status of blood donor and recipients are taken into account for compatibility testing. However, the phenotype of clinically significant blood group antigens on the donor red blood cells (RBCs) is required to be known at times when alloimmunization is particularly undesirable, such as in young females, pregnant women, and patients who are expected to require repeated transfusions in life, such as thalassemia or sickle cell disease patients. When selecting blood for transfusion to such patients, it would be useful if we have access to already phenotyped RBCs of donor population so that particular antigen typed blood can be given to such patients to prevent alloimmunization [
Racial differences in blood group antigen distributions are common and may result in striking and interesting findings. Very little information is available regarding distribution of various clinically significant minor blood group antigens in northern region of our country. The previous studies are done with limited number donors [
This prospective study was conducted in the department of transfusion medicine of a tertiary care hospital after approval by the Institutional Ethics Committee and a written informed consent given by the donors.
Blood samples were collected from 1,000 healthy regular repeat voluntary blood donors (who have donated two or more than two times before) between September 2010 and July 2011. Donors to be studied were arranged group-wise, that is, O positive: 34%, A positive: 22%, B positive: 32%, AB positive: 5%, and negatives: 7% as per the frequency of these blood groups in North Indian population [
The statistical analysis was carried out using Statistical Package for Social Sciences (SPSS Inc., Chicago, IL, version 15.0 for Windows). Qualitative or categorical variables were described as frequencies and proportions. Proportions for gender were compared using chi-square test. Gene frequencies were calculated using the Hardy Weinberg principle where
The study included 1,000 healthy regular repeat voluntary blood donors of which 947 were males and 53 were females. The males were significantly more than females with
Gene frequency of minor blood group antigens.
Amongst Rh antigens, e was the most common (99%) followed by D (93%), C (85.1%), c (62.3%), and E (21.5%) (Table
Comparison of antigen frequency of Rh subgroup antigens.
Antigens | Antigen frequency in total 1000 donors (%) | Antigen frequency in Indians by Thakral et al. [ |
Antigen frequency in Indians by Chaudhary et al. [ |
Antigen frequency in whites [ |
Antigen frequency in blacks [ |
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D | 930 (93.0%) | 93.4% | ND | 85% | 92% |
C | 851 (85.1%) | 84.8% | 95.2% | 68% | 27% |
c | 623 (62.3%) | 52.8% | 69.2% | 80% | 96% |
E | 215 (21.5%) | 17.9% | 15.4% | 29% | 22% |
e | 990 (99.0%) | 98.3% | 98.1% | 98% | 98% |
98.6% D negative donors had c antigen and 100% D negative donors had e antigen on their red cells. Thus, there is strong association of c antigen and e antigen with D negative donors. C antigen was found to be more associated with presence of D antigen as compared to its absence (90.8% and 10%, resp.) (Table
Comparison of antigen frequency of Rh subgroup antigens in D positive and D negative donors.
Antigens | Antigen frequency in D positive donors | Antigen frequency in D negative donors | Antigen frequency in total 1000 donors (%) |
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C | 90.8% | 10% | 851 (85.1%) |
c | 59.6% | 98.6% | 623 (62.3%) |
E | 22.8% | 4.3% | 215 (21.5%) |
e | 98.9% | 100% | 990 (99.0%) |
Amongst minor blood group antigens Kell antigen frequency was 2.8%, Duffy (
Antigen frequency of clinically significant minor blood group antigens.
Blood group antigen | In 1000 cases (%) | Indian study by Thakral et al. [ |
Indian study by Chaudhary et al. [ |
In whites [ |
In blacks [ |
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Kell (K) | 28 (2.8%) | 5.56% | 1.92% | 0.2% | <0.1% |
Fya | 873 (87.3%) | 86.8% | 73.1% | 17% | 9% |
Fyb | 583 (58.3%) | 56.2% | 53.8% | 34% | 22% |
M | 880 (88%) | 75.4% | 77.9% | 28% | 24% |
N | 575 (57.5%) | 61.5% | 73.1% | 22% | 30% |
S | 578 (57.8%) | 56.5% | 63.5% | 11% | 3% |
s | 875 (87.5%) | 87.4% | 45.2% | 45% | 69% |
Most common phenotypes in Duffy system were
Phenotype frequencies of Duffy blood group system.
Phenotype | In 1000 cases (%) | Indian study by Thakral et al. [ |
Indian study by Chaudhary et al. [ |
Indian study by Nanu and Thapliyal [ |
In whites [ |
In blacks [ |
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Fya−Fyb+ | 127 (12.7%) | 13.3% | 24% | 16.2% | 34% | 22% |
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0 (0%) | 0% | 3% | 0.44% | <0.1% | 68% |
Most common phenotypes were M+N− (42.5%), M+N+ (45.5%), S−s+ (42.1%), and S+s+ (45.4%). (Table
Phenotype frequencies of MN and Ss in MNS blood group system.
Phenotype | In 1000 cases (%) | Indian study by Thakral et al. [ |
Indian study by Nanu and Thapliyal [ |
In Europeans [ |
In African Americans [ |
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M−N+ | 120 (12.0%) | 24.6% | 14.6% | 22% | 30% |
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S+s− | 124 (12.4%) | 12.6% | 10% | 11% | 03% |
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S−s− | 1 (0.1%) | 0% | 1.2% | 0% | 01% |
Combined phenotype frequencies of MNSs in MNS blood group system.
Phenotype | In 1000 cases (%) | Indian study by Thakral et al. [ |
Indian study by Nanu and Thapliyal [ |
In Europeans [ |
In African Americans [ |
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M+N−S+s− | 65 (6.5%) | 7.9% | 5.5% | 5.7% | 2.1% |
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M+N−S−s+ | 151 (15.1%) | 15.8% | 22.6% | 10.1% | 15.5% |
M+N+S+s− | 50 (5%) | 3.5% | 4.6% | 3.9% | 2.2% |
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M−N+S+s− | 9 (0.9%) | 1.3% | 1.2% | 0.3% | 1.6% |
M−N+S+s+ | 45 (4.5%) | 9.5% | 3.5% | 5.4% | 4.5% |
M−N+S−s+ | 66 (6.6%) | 13.9% | 9.3% | 15.6% | 19.2% |
M−N+S−s− | 0 (0%) | 0% | 0.3% | 0% | 0.7% |
Besides ABO and Rh antibodies, antibodies to other clinically significant antigens are also known to cause HTR, HDFN, or shortened survival of transfused red cells [
In the present study the frequency of D and other Rh antigens was comparable with that of other studies from the region but was markedly different when compared to Whites and Blacks (Table
The antigen frequencies of Duffy and MNS antigens were comparable to antigen frequencies of other studies in this region but were different from that of white and black population (Table
The phenotype frequencies of Duffy and MNS blood group systems were compared with those of other studies from the region and with that of white and black population (Tables
The beta thalassemia carrier rate in India is around 3–7% with higher frequency in northwest India. Approximately 10,000 thalassemia major cases are added each year [
Kidd antigen evaluation in donors was not done due to cost constraints.
No author has a direct financial relation with the commercial identities mentioned in the paper that might lead to conflict of interests for any of the authors.