HLA-DR4 associated Dw types in rheumatoid arthritis

Frequencies of HLA-DR4 and its related Dw types were compared between randomly selected normal controls and the index cases of multiplex rheumatoid arthritis (RA) families. A DR4 frequency of 68.3% was observed in index cases (n = 57) compared to 31.2% in normal controls (n = 96). Cellular typing with homozygous typing cells (HTCs) revealed significant increases of Dw4 (49.1% vs 22.9% RR = 3.2 p less than 0.001) and Dw14 (22.8% vs 2.1% RR = 13.9 p less than 0.001) in the index cases. A non-significant increase was seen for Dw13 (8.8% vs 4.1%). When DR4 positive patients and controls were compared, a significant increase was seen only for Dw14 (34.2% vs 6.6% RR = 7.3 p less than 0.01). Data from HLA genotyped RA and normal families allowed an examination of haplotype combinations of HLA-B antigens and DR4/Dw types to be made. HLA-Dw4 was predominantly found with B44 and Bw62 with nearly all DR4/Bw62 haplotypes being Dw4 positive. HLA-Dw13 was associated with B44 and Dw14 with Bw60, B44 and B27. Based on HTC and normal family data. Dw10 was found to be strongly associated with B38 containing haplotypes. Analysis of 69 C4A, C4B complement typed DR4 haplotypes failed to show any statistically significant association between Dw type and "complotype". However, there was a suggestion of C4A3. BQO being associated with Dw4 (34.2% vs 16.1% X2 = 2.9 p = ns) and C4A3, B1 with Dw14 (45.5% vs 27.6% X2 = 2.1 p = ns).(ABSTRACT TRUNCATED AT 250 WORDS)