Novel class II HLA-DRB4 and DPB1 alleles found in the Belgian population

The most recent WHO Nomenclature report (Bodmer et al. 1992) included 37 HLA-DPB1 alleles. Characteristically, most DPB1 allelic sequences were generated by gene conversion events that resulted in different combinations of the six diversity regions within the polymorphic second exon. Using a highly refined HLA class II DNA typing technique to study the association of particular HLA class II polymorphisms with insulin-dependent diabetes mellitus (IDDM), we detected two previously undefined alleles, DRB4*0102 and DPB1*4601, in two unrelated persons of Belgian origin, one IDDM patient and one healthy blood donor, respectively. Inheritance of each of the two alleles was proven by typing the parents of each index case.