Prevalence of DRB1*01 and DRB1*04 alleles in a group of patients with rheumatoid arthritis living in Liguria.

Abstract

A major component of genetic susceptibility to rheumatoid arthritis (RA) appears to be explained by inheritance of HLA-DRB1 alleles. Multiple HLA-DRB1 alleles (DRB1*0401, *0404, *0405, *0408, *0101, *102, *1001 and *1402) encoding a shared epitope at amino acid positions 70-74 are associated with susceptibility to RA. There is ethnic variation in the clinical expression of RA and in both the frequency and type of HLA-DRB1 alleles carrying the shared epitope. We evaluated the prevalence of the alleles of HLA-DRB1 locus encoding for SE in 42 outpatients with RA attending the Rheumatology Center of the University of Genoa, Bruzzone Institute, and living in Liguria. A control group was composed of Italian marrow donors. DNA genotyping was performed using a low-resolution polymerase chain reaction technique for characterization of the families of HLA-DRB1 alleles for each of the 42 patients studied. Subsequently, subjects with *01 and *04 haplotype were tested with high-resolution HLA-DRB 1 typing to characterize the *01 and *04 alleles. No statistically significant differences were found in the prevalence of RA-associated single alleles *01 and *04 in the study group or in the control group. In contrast, the sum of susceptibility *04 alleles studied by resolution typing was strongly related to RA in the study group in comparison with the control group.