Imbalance in A2 and A2B phenotype frequency of ABO group in South India

Shastry, Shamee and Bhat, Sudha (2010) Imbalance in A2 and A2B phenotype frequency of ABO group in South India. Blood Transfusion, 8 (4). pp. 267-270.

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Background. The heterogeneity of A and B alleles results in weak variants of these antigens. Subgroups of A differ from each other quantitatively and qualitatively. The expected frequencies of A1 and A2 subtypes will be in Hardy-Weinberg equilibrium for the Mendelian inheritance of the allelic A1 and A2 genes. The frequency of A subgroups in the population from south India is not known. The aim of our study was to study the frequency of A subtypes and the prevalence of anti-A1 antibody among this population. Methods. Over a period of 3 years, patients' blood group was typed using a standard tube technique. Anti-A1 lectin studies were done for all patients with groups A and AB. Based on serological reactivity the samples were classified into A1/A1B, A2/A2B and weak A subgroups. The prevalence of A subgroups was determined. The significance of differences in proportions was analysed using the chi-square test. Results. A total of 40,113 patients’ samples were typed for ABO, Rh group and A subgroups in our blood bank attached to a tertiary care hospital. Among 10,325 group A samples, 98.14% classified as A1, 1.07% as A2, and 0.01% as weak A; the remaining group A samples were from neonates and reacted poorly with anti A1-lectin. The majority of AB samples (n=2,667) were of A1B type (89.28%). However, the proportion of A2B (8.99%) among AB samples was significantly higher than that of A2 in group A samples (p < 0.0001). The prevalence of anti-A1 antibodies among A2 and A2B samples was 1.8% and 3.75%, respectively, and none of them showed reactivity at 37°C.Conclusion. The results of our study show a significantly higher proportion of A2B subtypes than A2 subgroups. A similar imbalance is seen in blacks and Japanese. The incidence of anti-A1 antibodies is also higher among A2B patients

Item Type: Article
Uncontrolled Keywords: Subgroups; Anti-A1 lectin; A2; A2B
Subjects: Medicine > KMC Manipal > Immunohematology and Blood Transfusion
Depositing User: KMC Manipal
Date Deposited: 11 Mar 2013 06:53
Last Modified: 18 Oct 2016 11:30

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