Anti-topoisomerase 1 antibody level changes after B сell depletion therapy in systemic sclerosis

The aim of our study was to assess the relationship between the changes of antinuclear autoantibodies (ANA) and autoantibodies to topoisomerase 1 (anti-Topo 1) in systemic sclerosis (SSc) patients on rituximab (RTX) therapy. Materials and methods. The prospective study included 88 patients (73 women) with a mean age of 47 (17– 71) years. The mean disease duration was 5.9±4.8 years. The mean follow-up period was more than 2 years (27 (12–42) months). Results. We documented a statistically significant change in skin score, the disease activity index, improvement of pulmonary function and reduction of mean dose of prednisolone after RTX treatment. There was a significant decrease in the number of patients with high levels of ANA and overall decrease of the ANA and anti-Topo 1 levels. A moderate positive statistically significant correlation was found between ANA and anti-Topo 1 (r=0.403). In the group of patients positive for anti-Topo 1 there were a more pronounced depletion of B lymphocytes, significantly higher increase in forced vital capacity and diffusion capacity, decrease in the disease activity index, compared with a patients negative for anti-Topo 1. Conclusions. We observed the decline in the level of ANA and anti-Topo 1 in SSc patients after RTX therapy and it was correlated by an improvement of the main outcome parameters of the disease. Therefore, anti-Topo 1 positivity could be considered as a predictor of a better response to RTX treatment, especially in SSc patients with hyperproduction of anti-Topo 1.