The coexistence of systemic sclerosis and rheumatoid arthritis in five patients. Clinical and immunogenetic features suggest a distinct entity.

To elucidate the clinical characteristics and pathogenesis of scleroderma-rheumatoid arthritis (SSc-RA) overlap syndrome, we analyzed the clinical features of 5 patients with SSc-RA overlap. Their HLA phenotypes and genotypes were also determined. Generalized skin sclerosis, severe seropositive polyarthritis, pulmonary fibrosis, anti-topoisomerase I antibodies, and HLA-DR4,53;DQA1*0301;DBQ1*04 haplotype were observed in all of the patients. Similar clinical features were recognized in most of the 10 cases reported previously. Our case studies indicate that SSc-RA overlap may be a distinct entity.