Association between HLA-DRB1*15 and Japanese Patients with Rheumatoid Arthritis Complicated by Renal Involvement

Abstract

We performed serological phenotyping of HLA antigens in 175 patients with rheumatoid arthritis (RA) with (n = 41) and without (n = 134) renal involvement (RI), and DNA typing of HLA class II alleles in 75 patients. Among the patients with RA, the frequency of serologically determined HLA-DR4 was found to be significantly increased (odds ratio: 1.8, confidence interval: 1.3–2.5, p = 2.4×10^–4). In the patients without RI, the frequency of serological DR4 significantly increased (odds ratio: 2.2, confidence interval: 1.6–3.3, p = 2.6×10^–5). On the other hand, among the patients with RI, a serological determinant, DR15, did significantly increase (odds ratio: 2.7, confidence interval: 0.9–8.4, p = 1.2×10^–3) in comparison to the controls. At the DNA level, we found that the association of Japanese RA patients with serological HLA-DR4 was based on that with a genotype of HLA-DRB1*0405 (odds ratio: 2.4, confidence interval: 1.5–4.0, p = 4.4×10^–4) and also found an association of HLA-DRB1*1501 (odds ratio: 2.8, confidence interval: 1.2–6.6, p = 0.017) with RA patients having RI. Our results confirmed the association of HLA-DRB1*04 with RA over the ethnic barrier at the DNA level. Our results also suggested a distinct genetic effect of HLA-DRB1*1501 in the aspect of the susceptibility of RI in RA.