HLA‐SB in the south of France. Correlation between locally derived and reference typing reagents

Abstract

The HLA-D region of the major histocompatibility complex was subdivided since 1978 into 2 subregions separable by recombination: a telomeric subregion (closer to HLA-B), coding for the classical HLA-DR or Dw specificities as well as for the more recent MT series, and a centromeric subregion (closer to GLO [glyoxalase]), coding for a new series of alleles provisionally named SB (for secondary B cell antigens). Reagents allowing the identification of 6 independent alleles were characterized in 2 laboratories using the technology of primed lymphocytes typing. The existence of this new locus is supported by the following arguments: population studies by Shaw demonstrating 5 traits distinct from DR behaving as alleles, analysis of 2 informative SB/DR recombinant families, and, finally, studies of mutants showing independent loss of DR expression without loss of SB expression. The HLA-SB typing of 109 unrelated individuals from the south of France and segregation studies in 14 unrelated families are summarized; a first attempt to correlate local SB reagents with the NIH [National Institute of Health] reference standards is presented.