Tca: a high‐frequency blood group antigen

Abstract
An IgG antibody defining a high‐frequency red cell antigen was detected in the sera of two unrelated, nontransfused black women GT (gravida 1, para 0) and DLC (gravida 4, para 2). Inheritance of the antigen was established by the family study of DLC. The clinical significance of the antibody is not yet known. The antibody has been designated anti‐Tca, and the corresponding antigen, Tca. No Tc(a‐) individuals were found among 5000 Caucasians, 5000 Japanese, or 450 blacks; however, anti‐Tca was identified in the sera of two other unrelated black women (LZ and WM). A relationship between Tca and Cra has been proposed by other serologists, but further evidence is needed to confirm the association.