Association of anti phosphatidyl ethanolamine antibodies and low complement levels in systemic sclerosis patients--results of a cross-sectional study.

Some systemic sclerosis (Ssc) patients express antiphospholipid antibodies and their percentage varies within studies in the literature. The particular role of these antibodies in clinical manifestations of Ssc is still unknown. The aim of the study was to examine an extended panel of antiphospholipid antibodies in Ssc patients who did not have any clinical features of antiphospholipid antibody syndrome. A cross-sectional study was designed and 36 consecutive patients with Ssc were recruited. A relatively high proportion of patients (14 patients - 38.9%) had antiphospholipid antibody presence. Most Ssc patients (11 patients - 30.6%) had IgM anti phosphatidyl ethanolamine antibodies. Serum IgM anti phosphatidyl ethanolamine antibodies, IgM anti prothrombin and IgG anti β2 glycoprotein 1 antibodies were associated with low complement levels in Ssc patients. In multivariate analysis, only serum IgM anti phosphatidyl ethanolamine antibodies concentration and serum IgG anti β2 glycoprotein 1 antibodies concentration were independently associated with hypocomplementemia after adjusting for age and gender. No other correlations with Ssc clinical characteristics were found. In conclusion, antiphospholipid antibodies are present in a large proportion of Ssc patients who do not have clinical features or a history of antiphospholipid antibodies. IgM anti phosphatidyl ethanolamine antibodies seem to be more frequent and the dominant antiphospholipid antibody type in the group recruited from the Romanian Ssc population.