ICAM4

ICAM4

The LW blood system was first described by Landsteiner and Weiner in 1940. It was often confused with the Rh system, not becoming a separate antigen system until 1982. The LW and RhD antigens are genetically independent though they are phenotypically related and the LW antigen is expressed more strongly on RhD positive cells than on RhD negative cells. In most populations, the antithetical LW antigens, LWa and LWb are present as very high and very low frequency, respectively.