HLA and rheumatoid arthritis. A study of five families

Five families with two or more members ill with rheumatoid arthritis were investigated clinically. Tissue typing for HLA A, B, C and D/DR antigens was performed. We could not define may HLA haplotype associated with disease within these families. However, the prevalence of the haplotypes containing HLA-DR4 was high, suggesting a direct relationship between DR4 and increased risk of contracting rheumatoid arthritis.