Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Early Reconstitution of Autoreactive B-Cells After Rituximab Treatment in Primary Sjgren's Syndrome.

Abdulahad,  Wayel H., Tadema,  Henko, Vissink,  Arjan, Huitema,  Minke G., Anema,  Jetske, Meiners,  Petra M., Limburg,  Pieter C.

Background/Purpose:

B-cell depletion therapy with rituximab (RTX) leads to improvement of salivary and lacrimal gland function for at least 6–9 months in patients with primary Sjögren's syndrome (pSS). However, clinical symptoms of pSS re-appear at the time that B-cells return in the peripheral blood. This observation offers the possibility to analyze the impact of RTX on reconstitution of autoreactive B-cells in pSS-patients. In the present study, we aimed to assess the effect of RTX-treatment on anti-Ro52/60 and anti-La autoantibody-producing B-cells in patients with pSS.

Methods:

Seventeen patients with pSS were treated with RTX on days 1 and 15. To study the effect of RTX on depletion/reconstitution of autoreactive B-cells, peripheral blood mononuclear cells (PBMCs) were isolated from pSS-patients (at baseline and 5, 16, 24, 36, 48 and 60 weeks after RTX treatment) and from age- and sex-matched healthy controls (HC, n=12). These PBMCs were stimulated for 12 days with CpG-ODN and IL-2 to induce polyclonal B-cell activation and antibody production. In vitro produced autoantibodies to the Ro60-, Ro52-, and La- proteins were measured in supernatants by ImmunoCAP assay. Presence of circulating Ro52/60-specific B-cells was determined by flowcytometry, using APC-conjugated recombinant Ro52/60. To characterize the phenotype of autoreactive B-cells, CD19+ cells were sorted into 4 subsets on the basis of surface expression of IgD and CD27. These 4 subsets were separately co-cultured with autologous B-cell-depleted PBMCs (ratio 1:10 cells), and stimulated with CpG-ODN/IL-2 to analyze the levels of in vitro produced autoantibodies. In addition, B-cell numbers and phenotypes were examined by flowcytometry in fresh blood samples at aforementioned time points.

Results:

At baseline, B-cells from all pSS-patients produced high levels of anti-Ro60 and low levels of anti-Ro52 autoantibodies, whereas anti-La autoantibodies were detected in 7 out of 17 pSS-patients only. No autoantibody production was observed in HCs. In vitro autoantibody production in pSS-patients was disappeared at weeks 5 and 16 after B-cell depletion, reappeared at week 24, and reached baseline levels at week 36 post-RTX-treatment. At 36 weeks, reconstituted B-cell numbers were, however, still decreased as compared to their numbers at baseline. In addition, increased frequencies of Ro60-binding B-cells were observed in peripheral blood of pSS-patients by FACS analysis. Furthermore, B-cell-sorting experiments clearly demonstrated that IgD- memory B-cells were the major producers of anti-Ro60 autoantibodies.

Conclusion:

Circulating autoreactive B-cells in pSS-patients, bearing the phenotype of IgD- memory cells, produce high levels of anti-Ro60 autoantibodies. These autoreactive B-cells were successfully depleted by RTX, but early reconstituted despite the low numbers of regenerated B-cells. RTX-treatment might induce emerging autoreactive B-cells which in turn could be in favor of a more specific targeting of IgD- memory B-cells in pSS-patients.

To cite this abstract, please use the following information:
Abdulahad, Wayel H., Tadema, Henko, Vissink, Arjan, Huitema, Minke G., Anema, Jetske, Meiners, Petra M., et al; Early Reconstitution of Autoreactive B-Cells After Rituximab Treatment in Primary Sjgren's Syndrome. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :468
DOI:

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