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AB0626 Dynamic study of B-cells using highly sensitive flow cytometry (HSFC) in systemic lupus erythematosus patients’ receiving anti-B-cell therapy
  1. M.E. Tsanyan1,
  2. A. Aleksankin2,
  3. E.N. Aleksandrova2,
  4. S.K. Soloviev1,
  5. E.L. Nasonov3
  1. 1Laboratory of Lntensive Therapy
  2. 2Laboratory of Immunology and Molecular Biology
  3. 3Federal State Budgetary Institution “Research Institute of Rheumatology” of Russian Academy of Medical Sciences, Moscow, Russian Federation

Abstract

Objectives Dynamic study of B-cell using HSFC in systemic lupus erythematosus (SLE) patients’(pts) receiving anti-B-cell therapy with Rituximab (RTM) and definition of correlation with clinical and laboratory disease activity on the background of the therapy.

Methods 41 pts with definite SLE (7 male, 35 female; mean age Me 28 [23-40]) were included. 19 of them received a second course of RTM. 41pts were examined before treatment and after 1 month, 13 and 11 of them after 3 and 6 months respectively. SLE activity was assessed with SLEDAI2K scale. B lymphocytes number was evaluated using HSFC on BECKMAN COULTER CYTOMICS FC 500 (USA). Minimum detectable concentration of CD3-CD19+ was 1O103 cells/μl. 3pts received RTM in a total dose of 2000mg, 34pts 1000mg, 4pts 500 mg. Anti-double-stranded DNA (anti-ds-DNA) was assessed using immunoenzyme methods.

Results Before treatment B-cells was reduced in 25pts (El0,967 [0.17-2.45]%), compared to the other 16pts (El14.61 [9.43-19.37]%). At 1 month after therapy 25pts with reduced B-cell numbers exhibited complete depletion (El0[0-0.1]%, p=0.0002) and SLEDAI2K had lower values (Me 8 [4-14]) than in 16pts with incomplete depletion (El0.2665 [0.05-0.66]%, d=0.0004) with higher SLEDAI2K score (Me 10 [6-20]).

In the group of pts (n=3) receiving RTM in a total dose of 2000mg, 2pts had reduced number of B-cells but in 1pt number of B-cells was normal. At 1 month after RTM treatment all has developed a complete depletion. In the group of pts (n=4) receiving RTM in a total dose of 500mg, number of B-cells was also reduced. At 1month after treatment 3 of this pts exhibited complete depletion but in 1pt number of B-cells did not change and at 1 week after the infusion had developed rashes on the hands (delayed allergic reaction). In the group of pts (n=34) receiving RTM in a total dose of 1000mg, number of B-cells were also reduced El3,67[0,6-12,89]%. In this group, at 1 month after therapy pts exhibited incomplete depletion El0,07 [0-0,333]%, d=0.

Correlation analysis of B cells and SLE activity showed a significant association between the number of B-cells, the level of anti-ds-DNA and the SLEDAI2K index before treatment and after 1,3,6 months. Number of B cells also correlated with the level of C3,C4 components of complement before therapy and with the C3 component at 1 month after therapy. Found no correlation between levels of C3,C4 and B-cells at 3,6 months after therapy RTM.

Conclusions The number CD3-CD19+ lymphocytes was associated with clinical and laboratory activity of SLE: SLEDAI2K, anti-ds-DNA. After treatment reduction in the number of B-lymphocytes correlates with decreased levels of anti-ds-DNA and the index SLEDAI2K through 1,3,6 months after therapy RTM. Found no correlation of B cells and C3,C4 complement components.

Disclosure of Interest None Declared

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