The prevalence and significance of anti-PM/Scl antibodies in systemic sclerosis

Introduction. Anti-PM/Scl (a-PM/Scl) antibodies are found in different systemic autoimmune diseases such as polymyositis, dermatomyositis, systemic sclerosis (SSc) and overlap syndromes. According to literature, they are detected in approx. 2% of SSc patients, but their presence is more common in SSc with myositis overlap. Objective. The aim of the study was to assess the prevalence of a-PM/Scl in patients with SSc and to identify differences in the clinical profile of the disease in patients with the presence of a-PM/Scl. Materials and method. The study was performed on 126 European Caucasian SSc patients (98 females and 28 males) hospitalized consecutively in the Department of Rheumatology and Connective Tissue Diseases. The study group was analyzed for the potential presence of a-PM/Scl using a commercial test - EUROLINE Systemic Sclerosis Profile. The detection and interpretation were carried out electronically using the specific Euroimmun - EUROLineScan programme. The subtype of SSc, incidence of internal organ involvement and serological profile were determined in the entire group. Due to the presence of a-PM/Scl, patients were divided into two groups: a-PM/Scl (+) SSc - 22 patients and a-PM/Scl (-) SSc - 104 patients. Results. A-PM/Scl was detected in 22/126 patients with SSc (17.5%). A strong correlation was found between a-PM/Scl and myalgia or myositis (p = 0.0379), hand joints contractures (p = 0.0002) and the prevalence of overlap syndrome (p = 0.0142). There were no relationships between the presence of a-PM/Scl and subtypes of SSc, other organ involvement, digital ulcers or calcinosis. Conclusions. Anti-PM/Scl antibodies are fairly common in patients with systemic sclerosis. In SSc, anti-PM/Scl antibodies are frequently associated with myalgia or myositis, hand joint contractures and an overlap syndrome.