Objective: To explore the expression of regulatory B cells (Bregs) in peripheral blood of patients with systemic lupus erythematosus (SLE) and elucidate the function of Bregs in the pathogenesis of SLE.
Methods: A total of 38 active SLE patients, 22 inactive SLE subjects and 20 healthy controls were enrolled. The expressions of IL-10+ CD19+ Breg and CD19+ CD24hi CD38hi Breg in peripheral blood mononuclear cells (PBMC) were evaluated by flow cytometry. And IL-10 was measured in the culture supermatants by enzyme-linked immunosorbent assay (ELISA).
Results: The expression of IL-10+ CD19+ Breg in PBMCs of active SLE patients was (1.54±0.64)%. And it was lower than those in inactive SLE patients (2.42±0.75)% (P<0.01) and healthy controls (4.35±1.00)% (P<0.01). And the expression of CD19+ CD24hi CD38hi Breg was (1.26±0.45)%. Also it was lower than those in inactive SLE subjects (2.01±0.61)% (P<0.01) and healthy controls (3.14±0.87)% (P<0.01).The level of IL-10 significantly decreased in culture supermatants of active SLE patients. And it was lower than those in inactive SLE subjects (P<0.05) and healthy controls (P<0.01). The percentage of IL-10+ CD19+ Breg and CD19+ CD24hi CD38hi Breg in PBMCs of SLE patients was positively correlated with the level of IL-10 in culture supernatants (r=0.652, P<0.01 and r=0.574, P<0.01).
Conclusion: The expression of IL-10-related Bregs significantly decreases in PBMCs of active SLE patients. And Bregs may play some role in the pathogenesis of SLE.