An update on the Lewis blood group system

This update of the Lewis blood group system (Combs MR. Lewis blood group system review. Immunohematology 2009;25:112–8) describes new information on the clinical significance of Lewis antigens regarding susceptibility of individuals to certain diseases and the possible role of bacteria in Lewis expression. This update also describes recently reported examples of Lewis antibodies causing hemolytic transfusion reactions. No new antigens have been identified in the International Society of Blood Transfusion system 7, leaving the antigen count to stand at six: Le^a, Le^b, Le^bH, ALe^b, BLe^b, and Le^ab.