Presisposing and protective HLA-DR and DQ alleles for rheumatoid arthritis in South African mixed-ancestry and Xhosa populations

Rousseau, J; Pokorny, L; Glaser, J; Creemers, P C

Presisposing and protective HLA-DR and DQ alleles for rheumatoid arthritis in South African mixed-ancestry and Xhosa populations

Journal Article

2003

Journal Title

South African Journal of Science

Link to Journal

https://www.sajs.co.za/

Publisher

University of Cape Town

Department

Department of Clinical Laboratory Sciences

Faculty

Faculty of Health Sciences

Abstract

We have investigated the distribution of the HLA-DRB1, -DQA1 and -DQB1 alleles in rheumatoid arthritis (RA) by comparing the allele frequencies in blood from 65 Cape coloured (mixed-ancestry) RA patients and 114 controls, and from 25 Xhosa RA patients and 94 controls. The strongest positive association with RA was found for the DRB10401 allele, followed by the DQA10301 and DQB10302 alleles, which are strongly linked with DRB10401. Data for both populations were statistically significant. In addition, DQB10501, which is in linkage disequilibrium with DR1 and DR10, showed a positive association with RA. These findings are in agreement with those for Caucasoids; they indicate that haplotypes that predispose for RA are highly conserved during evolution. Negative associations, that is, a protective effect for RA, were also found, but only for broad specificities; the associations were generally weaker. New findings were negative associations for DRB103, DRB10701, DQA10501 and DQB106. The DRB10301 and DQA10501 alleles are in linkage disequilibrium; a negative association was found in both populations. The negative association of DRB10701 was found only in the mixed-ancestry population and was absent in Xhosa. The effect of DQA106 was significant in both populations. Thus, the protective HLA-DR and DQ alleles show a greater ethnic diversity.