Lack of an association between diffuse systemic sclerosis and HLA-DR1 or HLA-DR5

The HLA-DR locus of the major histocompatibility complex encodes class II molecules which participate in immune responses through regulation of T cell interaction with antigen presenting cells. Previous association studies between HLA-DR antigens and the autoimmune disease, systemic sclerosis (or scleroderma), have yielded conflicting results. Some investigators have reported an association between this disease and HLA-DR1, while others have demonstrated an association with HLA-DR5. In this study, we used restriction fragment length polymorphisms in the HLA-DR locus to compare allelic frequencies of HLA-DR1 and HLA-DR5 in scleroderma patients with diffuse disease and healthy control subjects. No significant difference in the allelic frequency of either antigen was observed between the groups. These results suggest that HLA-DR1 and HLA-DR5 antigens are unlikely to contribute significantly to disease susceptibility in scleroderma.