Study of ABO Blood Groups and Subgroups A1, A2, A1B and A2B in Blood Donors and Recipients

ABSTRACT

Blood transfusion in modern era is possible only due to the knowledge of exact blood groups and sub blood groups. Over 700 erythrocyte antigens have been reported and are organized into 35 blood group systems by International Society of Blood Transfusion. These antigens may be proteins, glycoproteins or glycolipids and are controlled by single or more gene locus. Some antigens are specific to red cells; whereas, others are found on other cells throughout the body. The ABO blood group was the first human blood group to be discovered by Landsteiner in 1900 and it served the beginning of Blood Banking and Transfusion Medicine. Numerous mutations are found in A, B and O genes, but the most common mutation is A2. The A2 gene has two nucleotides different from the A1 gene which results in diminished enzymatic activity and consequently, weakened antigen expression. Distinction between A1 & A2 made by testing red cells with the lectin from Dolichos biflorus. Prospective study on 2000 cases to find the frequency of ABO and sub blood groups to reduce the blood transfusion related reactions. Methods: The present study included 2000 blood sample collected in the Department of Blood Banking, Govt. Medical College and Hospital, Amritsar and in voluntary blood donation camps organized by the department. 4 ml of venous blood sample collected. 2ml of blood put into ethylene diamine tetra acetic acid (EDTA) vial and remaining 2ml transferred to test tube and allowed to clot. The EDTA sample used for forward grouping and serum used for reverse grouping. Results: In our study the frequency of blood group B was the highest 37.8%, blood group O was 31.8%, blood group A was 21.2% and group AB was the least common with 9.2%age. In case of sub groups, A1 was 20.10% (highest in sub groups) and A2B was 0.85% (Lowest). The Rh +ve blood group was 94.1% and Rh –ve was 5.9%. Conclusion: The study is concluded with the suggestion that, as already being carried out, ABO, Rh blood grouping and sub grouping should be done in each and every case to reduce the blood transfusion related complications. More work should be carried out in different parts of state to know the distribution pattern of ABO, Rh blood groups and sub groups. This will also help the Blood Banks to estimate the requirement of different blood groups and sub groups.