Association between HLA-DRB1*15 and Japanese patients with rheumatoid arthritis complicated by renal involvement

We performed serological phenotyping of HLA antigens in 175 patients with r heumatoid arthritis (RA) with (n = 41) and without (n = 134) renal involvem ent (RI), and DNA typing of HLA class Il alleles in 75 patients. Among the patients with RA, the frequency of serologically determined HLA-DR4 was fou nd to be significantly increased (odds ratio: 1.8, confidence interval: 1.3 -2.5, p = 2.4 x 10(-4)). In the patients without RI, the frequency of serol ogical DR4 significantly increased (odds ratio: 2.2, confidence interval: 1 .6-3.3, p = 2.6 x 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 x 10(-3)) in comparison to the cont rols. At the DNA level, we found that the association of Japanese RA patien ts with serological HLA-DR4 was based on that with a genotype of HLADRB1*04 05 (odds ratio: 2.4, confidence interval: 1.5-4.0, p = 4.4 x 10(-4)) and al so found an association of HLA-DRB1*1501 (odds ratio: 2.8, confidence inter val: 1.2-6.6, p = 0.017) with RA patients having RI. Our results con firmed the association of HLA-DRB1*04 with RA over the ethnic barrier at the DNA level. Our results also suggest ed a distinct genetic effect of HL4-DRB1*15 01 in the aspect of the susceptibility of RI in RA.