Anti-Tcb, an antibody that defines a red cell antigen antithetical to Tca.

A patient's serum, used as a source of anti-Goa typing serum, was found to contain a second antibody that detected a 'new' red cell antigen present in approximately 5 percent of blacks, but not yet found in Caucasians. Among blacks, the 'new' antigen shows an antithetical relationship to the high frequency antigen Tca, as evidenced by tests on eight unrelated Tc(a-) black women and the families of two of these propositi. The antigen, designated Tcb, has not been found on the red cells of Tc(a-) persons whose racial origins differ from the propositi of this report, which suggests that more than one genetic mechanism can produce the Tc(a-) phenotype. The presence of both anti-Goa and anti-Tcb in the same serum appears to be a coincidental and unrelated finding.