Association of HLA-DR with progressive systemic sclerosis in Japanese.

Abstract

Our observations show the extreme difference of genetic background of a-Scl-70 positive PSS, with regard to HLA-DR, between Japanese and other ethnic groups including Caucasian and American black persons. The increase in DRB1*1502-DRB5*0102 haplotype supported the hypothesis of Reveille, et al that uncharged polar amino acid residue at position 30 of HLA-DQB1 allele was important for a-Scl-70 positive PSS because close association of the haplotype with DQB1*0601 was well established in Japanese; listed as a hypothetical candidate of PSS susceptible DQB1 allele. DRB1*0802 were also associated with hypothetical candidates of DQ alleles. Furthermore, the sharing of the particular amino acid sequence: valine38 and phenylalanine67-lysine68-glutamic acid69-asparic acid70-arginine71, by DRB5*0102, DRB1*0802 and DR11 (associated with Caucasian PSS) also suggests a contribution of the sequence in HLA-DR molecules to the pathogenesis of PSS according to the shared epitope hypothesis.