BgbExpression in Relation to the HLA-B17 Antigen Splits Bw57 and Bw58 and the Cross-Reactions of Anti-BgbAntibodies1

A substantial number of individuals typed as HLA-B17 do not have Bgb. To determine whether or not this discrepancy reflects genetic or ethnic group differences or the influence of B17 antigen subtypes, a large number of unrelated and related B17 individuals from the Caucasian, Hispanic, Black and Chinese ethnic groups were tested in parallel for Bgb and Bw57- or Bw58- B17 subtype. Higher Bgb expression was found in association with Bw57, but differences in expression of Bgb were also seen in different ethnic groups and in different related individuals carrying the same Bw57 or Bw58 haplotype. Genetic factors other than HLA thus influence the expression of HLA antigens on red cells. Standard and antiglobulin lymphocytotoxicity tests indicate that all Bgb typing sera contain anti-Bw57 antilymphocyte antibodies and most also contain anti-Bw58 and cross-reacting anti-B12, B15 and/or Bw49 antibodies.