Session Title: B cells in Human and Animal Arthritis
Session Type: Abstract Submissions (ACR)
Background/Purpose: IgG4 related disease (IgG4-RD) is a chronic, multisystem-involved autoimmune disease. Abnormally activated and differentiated B cells may play important roles. Regulatory B cells (Breg) are newly defined B cell subgroups with immunosuppressive functions. In this study, we investigated the differences of B cell subsets, the expressions of co-stimulatory molecules on B cells, and the function of Breg cells in the peripheral blood of patients with IgG4-RD, primary Sjögren’s syndrome (pSS), and healthy donors.
Methods: We recruited 38 newly diagnosed IgG4-RD patients, 38 newly diagnosed pSS patients and 30 healthy volunteers were included as disease and healthy controls. To analyze B cell subsets and B cell activity, PBMCs were surface stained with CD19, CD24, CD38, BAFF-R, CD40, CD80 and CD86 mAbs and then detected by flow cytometry. The function of Bregs was tested by co-culturing of isolated CD19+CD24hiCD38hi Breg cells with purified CD4+CD25- effector T cells. Serum cytokines were measured by ELISA. Correlation of clinical data and laboratory findings were measured as well.
Results: Compared with pSS patients and healthy controls, IgG4-RD patients had a lower frequency of peripheral mature B cells and Breg cells. Interestingly, CD19+CD24-CD38hi B cell subsets were significantly higher in peripheral blood B cells from new-onset IgG4-RD patients than in pSS patients and healthy controls. The expression of BAFF-R and CD40 on B cells was significantly lower in IgG4-RD patients compared with those in pSS patients and healthy controls. Whereas, the expression of CD86 and CD80 on B cells was significantly increased in IgG4-RD patients compared with those in pSS patients and healthy controls. Unlike healthy B cells, CD19+CD24hiCD38hi Breg cells from pSS patients were lack of suppression function.
Conclusion: B cells in patients with IgG4-RD and pSS display a variety of abnormalities including disturbed B cell subpopulations, abnormal expression of key signaling molecules, co-stimulatory molecules. A significantly increased B cell subset, CD19+CD24-CD38hi B cells may play an important role in the pathogenesis of IgG4-RD.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/b-cell-subsets-and-dysfunction-of-regulatory-b-cells-in-igg4-related-diseases-and-primary-sjogren-syndrome-the-similarities-and-differences/