A1 and A2 subtypes of blood group A

Abstract

Objective To determine the prevalence of A1 and A2 blood subgroups and detect anti-A1 antibodies in the studied population to assess their implication in transfusion practice. Background The A blood type contains ∼20 subgroups, of which A1 and A2 are the most common. The distinction between the A1 and A2 subgroups is usually made by using anti-A1 lectin. A2 and A2B subgroups might have anti-A1 antibody, which become clinically significant if they react at 37°C and may lead to hemolytic transfusion reaction. Patients and methods Blood samples were collected from 10 662 participants attending Fayoum University Hospital Blood Bank over a period of 8 months. Analysis of ABO and Rh-D blood groups using column-agglutination technique was done. Subgrouping using anti-A1 lectin was performed for A and AB blood groups. Anti-A1 antibodies detection using AHG microcolumn was done for A2 and A2B subgroups. Results Blood group A was present in 40.1% (4274 participants), of whom 39.8% were A1 and 0.3% were A2, whereas group AB was present in 7.8% (836 participants), of whom 6.3% were A1B and 1.5% were A2B. Anti-A1 antibodies were not detected in any of the subgroups A2 and A2B. Conclusion Despite the large population sample of this study, A2 and A2B are rare subgroups and were only found in 195/10 662 (1.8%) of studied samples, and anti-A1 antibodies were not detected. However, implementation of A1 and A2 grouping is vital to avoid any reactions that could occur from these minor incompatibilities, leading to overall improvement in blood transfusion practice.