THU0345 EFFECT OF THE LONG-TERM RITUXIMAB TREATMENT ON B-LYMPHOCYTES AND ANTINUCLEAR AUTOANTIBODY LEVEL IN PATIENTS WITH SYSTEMIC SCLEROSIS
Authors: L. Garzanova, L. P. Ananyeva, O. Koneva, O. Desinova, O. Ovsyannikova, M. Starovoytova, S. Glukhova, M. Cherkasova, A. Aleksankin
Journal: Annals of the Rheumatic Diseases (2020)

Background: Anti-B-cell therapy is seen as a promising therapeutic option for systemic sclerosis (SSc). The study of antinuclear antibody levels during treatment with rituximab (RTX) in patients (pts) with SSc could have theoretical and practical interest. Objectives: To assess the changes in ANA, anti-topoisomerase-1 (Scl-70) levels and B-lymphocytes (B-lymph) count during RTX therapy during prospective observation. Methods: This prospective study included 88 pts with SSc, 83% of them had interstitial lung disease and 75% had positive Scl-70 autoantibody. The mean age was 47 yrs (17-71), female-73 pts (83%), the diffuse cutaneous subset of the disease had 50 pts (57%). The mean disease duration was 5,9±4,8 yrs. The mean follow-up period was 27 months (12-42). The cumulative mean dose of RTX was 2,9±1,1grams. All patients received prednisolone at a dose of 11,7±4,4 mg, immunosuppressants received 42% of them. Patients were divided into groups depending on the duration of the disease: group 1 (n=33) - up to 3 yrs, group 2 (n=25) - from 3 to 6 yrs, group 3 (n=30) - more than 6 years (6-18yrs). The results are presented in the form of mean values, median, upper and lower quartiles. Results: Parallel to clinical improvement in most patients (96%) we found positive changes in many parameters at the end of the study compared to the baseline. The Rodnan skin score decreased from 11,21±9,33 to 6,19±4,74 (p&lt;0,001). The disease activity index (EScSG-AI) decreased from 2,9±1,74 to 1,36±1,15 (p&lt;0,001). Forced vital capacity, % predicted, increased from 76,35±19,65 to 84,37±21,04 (p&lt;0,001). Diffusing capacity for carbon monoxide, % predicted, increased from 45,56±17,72 to 47,62±16,96 (p&lt;0,019). The dose of prednisolone decreased from 11,7±4,4 to 9,2±3,2 mg (p&lt;0,001). The absolute number of B-lymph decreased from 0,224±0,19 to 0,0175±0,058 (p&lt;0,001). The pts of the group 1 showed the highest values of B-lymph at baseline and level of B-lymph decreased from 0,326±0,22 to 0,008±0,01 (Δ 0,318) at the end of the study. In group 2 depletion was less pronounced (from 0,197±0,14 to 0,026±0,07 (Δ 0,171) and the lowest depletion was observed in group 3 (from 0,151±0,16 to 0,019±0,07 (Δ 0,131), p&lt;0,001 for all groups. An initially positive ANA was found in 92% of pts (range 1/320-1/1280). During observation, the number of pts with high (1/640-1/1280) ANA titers decreased from 70 to 41 (p&lt;0,001), and the average level of ANA decreased by 30-40% in all groups. At baseline 63 pts (75%), had positive Scl-70 with equal levels in all groups. At the end of the study level of Scl-70 decreased from 125,02±89,12 to 108,6±86,89 units/ml (p&lt;0,007). A negative correlation was found between the duration of the disease and ANA (r = -0,54; p&lt;0,003) and Scl-70 (r = -0,44; p&lt;0,017). Conclusion: In our study a clinical improvement was shown in most pts at the long-term complex therapy, including RTM. We found a significant decrease in the absolute number of B-lymph, as well as decrease of ANA and Scl-70 levels. Initially pts with a short duration of the disease had a higher level of B-lymph and in these pts depletion was more pronounced, compared to those with a longer duration of the disease. However, the level of Scl-70 and ANA decreased both to those who started RTX therapy at an early stage of the disease (&lt;3yrs) and to those who had a long disease duration. Disclosure of Interests: None declared