Standardized Lectin in the Prevention of Blood Group Incompatibility

Background-The two principal subgroups of A antigen are A1 and A2. About 80% of group A individuals have red blood cells (RBCs) that are agglutinated by anti-A1. At appropriate dilution, Dolichos biflorus (lectin) acts as an anti-A1 and agglutinates A1 but not A2 RBCs. The main goal of this study was to test and introduce a standardized lectin in order to differentiate the subgroups of A antigen in Iran.Methods-The powder form of the plant Dolichos biflorus was subjected to a series of sequential operations according to current standard protocols with some modifications. The prepared reagent was used to detect A1 and A2 cells based upon the agglutination reaction. The reagent was initially used to detect incompatibility reaction in 450 transfused patients at Al- Zahra teaching hospital (Isfahan, Iran) and all the results were rechecked using a standard lectin.Results-Five of 450 patients with blood group A or AB showed incompatibility with a high anti-A1 titer after transfusion of isogroup blood. Among them, 2 patients were of A2 and 3 were of A2B types. The same results were obtained by using standard lectin. Conclusion-Considering the great importance of subgroup incompatibility in transfusion medicine, we recommend the use of standardized lectin for the differentiation of A antigen subgroups before transfusion of RBCs containing the A antigen.