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.