Anti-U-like: a common antibody in Black individuals

Background and Objectives Anti-Uz, a scarce antibody, defines a glycophorin B high-incidence antigen, which is protease-sensitive. In a few years, we have encountered 12 antibodies of similar specificity, made by Black individuals of the S− s+ U+ phenotype. Materials and Methods Antibodies were characterized by serological methods, with common and rare MNS types, as well as red cells treated with various proteases. Results Anti-U-like, mostly an autoantibody, was of IgG class and reacted optimally by indirect antiglobulin test at 20 °C. The corresponding antigen was destroyed by several proteases. Tests with papain-treated or Dantu+ cells suggested the existence of several subspecificities. Conclusion Anti-U-like is common in the African population, though its reactions are often misinterpreted. The fact that antibody producers are always Black patients remains unexplained. No relationship with a pathological state could be established.