Intra HLA–D Region Recombinant Maps HLA–DR between HLA–B and HLA–D

Abstract

A consanguineous family was typed for HLA-A, B, C, D, DR and [glyoxylase], Bf [properidin factor B], C2 [complement component 2] and C4 and other red cell markers. An expected Dw7 homozygous sibling is a Dw1/Dw7 recombinant, probably derived from a crossing over between DR and D on the paternal haplotypes. The anomalous typing by Dw1 histocompatibility antigen serum of the recombinant haplotype are best explained by the likely presence of an additional Lad polymorphism which could be a serologically detectable 2nd epitope on the same molecule as the HLA-D determinant or in the form of 2 linked chains, 1 encoded by HLA-D and 1 by another Lad gene in the HLA haplotype.