Dynamics of lymphocyte subpopulations, CD4+CD25+CD127- T regulatory cells in patients with rheumatoid arthritis during therapy with the rituximab biosimilar Acellbia

Abstract

Objective: to evaluate the effect of the rituximab (RTM) biosimilar Acellbia on the peripheral blood levels of CD3+, CD3+CD4+, CD3+CD8+, CD16+CD56+, CD19+, and CD4+CD25+CD127- lymphocytes in patients with rheumatoid arthritis (RA).Patients and methods. Examinations were made in 20 RA patients who received 2 RTM infusions at a total dose of 1200 mg. The levels of C-reactive protein, IgM rheumatoid factor, IgG, IgM, and IgA were measured by a nephelometric method. The relative and absolute contents of CD3+, CD3+CD4+, CD3+CD8+, CD16+CD56+, CD19+, CD4+CD25+CD127- T regulatory cells (Tregs) were estimated by multicolor flow cytofluorometry.Results and discussion. At week 24 of RTM therapy, there was a good/satisfactory effect according to EULAR criteria in 17 (85%) patients; DAS28 remission in 4 (20%), and SDAI remission in 2 (10%). The use of RTM was accompanied by a significant increase in the relative content of CD4+CD25+CD127- T lymphocytes, the median of which at weeks 12 and 24 after therapy initiation increased from 6.8 [5.2; 7.6]% to 7.3 [6.1; 8.3] and 6.97 [6.4; 8.2]%, respectively (p<0.05). The absolute peripheral blood count of Tregs tended to increase at weeks 12 after the first infusion of the drug (up to 0.05 [0.04; 0.075] ⋅ 109 /l; p=0.05). At week 24 follow-up, the patients who achieved SDAI remission/low disease activity had significantly higher baseline relative Tregs levels (7.35 [6.8; 7.97]% than those with the moderate activity of the pathological process (5.8 [4.3; 7.22] %; p<0.05).Conclusion. The use of the RTM biosimilar is accompanied by the development of complete depletion of CD19+ lymphocytes and by an increase in CD3+ and CD3+CD4+ lymphocytes and Tregs. The larger baseline number of CD4+CD25+CD127- lymphocytes is associated with the higher efficiency of RTM therapy.