Anti-CCP antibodies and rheumatoid factor in systemic sclerosis: Prevalence and relationships with joint manifestations

BACKGROUND: It is known that anti-citrullinated protein (a-CCP) antibodies and rheumatoid factor (RF) can be present in systemic sclerosis (SSc) patients, particularly with joint involvement. OBJECTIVES: The aim of the study was to assess the prevalence of a-CCP antibodies and immunoglobulin M class (IgM) RF, and the relationships between their presence and joint manifestations in patients with SSc. MATERIAL AND METHODS: The study included 100 European Caucasian SSc patients hospitalized consecutively in the Department of Rheumatology and Connective Tissue Diseases (Lublin, Poland). Anti-citrullinated protein antibodies and IgM RF were determined using a commercial enzyme-linked immunosorbent assay (ELISA) test. RESULTS: Anti-citrullinated protein antibodies were found in 10 out of 100 (10%) SSc patients and IgM RF in 71 out of 100 (71%) SSc patients. In the study, 90/100 (90%) SSc patients had joint manifestations (arthralgia or arthritis), 34/100 (34%) had arthritis and 6/100 (6%) had a systemic sclerosis-rheumatoid arthritis (SSc-RA) overlap syndrome. Significantly higher a-CCP antibody levels (p = 0.012), erythrocyte sedimentation rate (ESR) (p = 0.029) and C-reactive protein (CRP) levels (p = 0.020) were observed in the SSc group with arthritis. A significant correlation was found between the group with arthritis and the presence of a-CCP antibodies, and between the arthralgia group and the presence of IgM RF. CONCLUSIONS: The prevalence of RF and a-CCP antibodies is relatively high in SSc, and joint involvement occurs frequently. There was a significantly higher prevalence of IgM RF in the group with joint manifestations. About 1/3 of SSc patients had symptoms of arthritis. Arthritis is connected with the presence of a-CCP antibodies, while arthralgia is connected with the presence of IgM RF.