An Unusual Rh Phenotype Indicating Heterogeneity of the Cw Antigen

Abstract
A family is reported in which a new Cw antigen occurred in two generations. This was recognized by 17 anti‐Cw sera, but by none of the 21 anti C sera which were, however, shown to react strongly with common Cw+ cells. This unusual finding provides evidence that the Cw antigen is in fact heterogeneous. On the basis of data obtained from absorption‐elution and coagglutination studies a tentative explanation is attempted: common Cw+ phenotypes are assumed to be Cw (+1+2) and the present phenotype Cw (+1–2). Anti‐Cw sera should accordingly be anti‐Cw1, whereas anti‐C sera should only react with Cw2.