Anti-A1Leb: a mind boggler.

The Lewis blood group system is unique because antigens are neither alleles of the same gene nor are they synthesized by red blood cells (RBCs); rather, they are adsorbed onto the RBC membrane from plasma as glycolipids. Antibodies against Lewis antigens are predominantly naturally occurring immunoglobulin (Ig)M type that sometimes react at 37°C and the antihuman globulin phase. Lewis compound antigens, ALeb and BLeb, have been described that were confirmed because of the presence of antibodies against them. These compound antigens are the result of an interaction between ABO, H, SE, and LE genes.The Lewis blood group system is unique because antigens are neither alleles of the same gene nor are they synthesized by red blood cells (RBCs); rather, they are adsorbed onto the RBC membrane from plasma as glycolipids. Antibodies against Lewis antigens are predominantly naturally occurring immunoglobulin (Ig)M type that sometimes react at 37°C and the antihuman globulin phase. Lewis compound antigens, ALeb and BLeb, have been described that were confirmed because of the presence of antibodies against them. These compound antigens are the result of an interaction between ABO, H, SE, and LE genes.

Retrospective analysis of forward and reverse ABO typing discrepancies among patients and blood donors in a tertiary care hospital.

OBJECTIVE: The aim of our study was to determine the incidence and causes of ABO typing discrepancies among patients and blood donors at our centre. BACKGROUND: An accurate interpretation of the ABO blood group of an individual is of utmost importance to ensure patient safety and good transfusion practices. METHODS: A retrospective observational study was carried out in the Department of Transfusion Medicine in our hospital from March 2013 to December 2015. Records of all patient and blood donor samples were retrieved and analysed for ABO typing discrepancies. RESULTS: In total, 135 853 patient and 62 080 donor samples were analysed for ABO typing discrepancies. The incidence among patients and blood donors was found to be 0·1% (138/135853) and 0·02% (14/62080), respectively. The mean age for patients and blood donors was 48·4 and 29·2 years, respectively. The most common cause of ABO typing discrepancies was due to cold autoantibodies among the patients (50·7%) and blood donors (57%) causing discrepant results in reverse typing. The various other causes of reverse typing discrepancies among patients were weak/missing antibody (25·4%), cold-reacting alloantibody (4·3%), warm autoantibody (2·2%), anti-A1 antibody (2·2%), Bombay phenotype (1·5%), transplantation (0·7%) and rouleaux (0·7%), whereas in blood donors, the causes were cold-reacting antibody (7%) and weak antibody (7%). The major cause of forward typing discrepancies among patients (12·3%) and blood donors (29%) was ABO subgroups. CONCLUSION: The resolution of ABO typing discrepancy is essential to minimise the chance of transfusion of ABO-incompatible blood.