Reduced CD37 expression in B cell subsets after stimulation and its clinical relevance in primary Sjögren's syndrome

This study aims to analyse the expression of CD37 in different B cell subsets from human peripheral blood, exploring changes in CD37 expression in B cells of patients with primary Sjögren's syndrome (pSS) and assessing their clinical relevance.

A total of 32 pSS patients and age- and sex-matched healthy controls were included. Peripheral blood mononuclear cells (PBMCs) were isolated, and B cells were classified into five subsets using flow cytometry based on CD24 and CD38 expression. CD37 expression was evaluated, and functional differences between CD37+ and CD37- B cells were compared. Peripheral lymphocytes were stimulated with LPS to observe changes in CD37 expression. The expression of CD37 and related B cell subsets was also compared between pSS patients and healthy controls, followed by ROC curve analysis.

CD37 was highly expressed in early-stage B cells, with a significant decrease in effector cells. CD37+ B cells exhibited higher proportions of CD40+, HLA-DR+, and IL-10+ cells, indicating enhanced antigen-presenting and regulatory capabilities. Post-LPS stimulation, CD37 expression significantly declined in pSS patients compared to healthy controls, suggesting increased sensitivity to differentiation into plasma cells. Additionally, CD37-related B cell subsets in pSS patients showed strong correlations with autoantibodies and immunological markers. ROC analysis revealed substantial areas under the curve, confirming the diagnostic potential of these subsets.

The expression of CD37 in B cell subsets is variable, indicating a potential regulatory role in B cell function and offering auxiliary diagnostic value in pSS.