Expression of CD19+CD24highCD38high B cells, IL‑10 and IL‑10R in peripheral blood from patients with systemic lupus erythematosus.

The present study aimed to examine the status and clinical significance of cluster of differentiation (CD) 19+CD24highCD38high regulatory B cells (Bregs), serum interleukin (IL)‑10, serum transforming growth factor (TGF)‑β and IL‑10 receptor (IL‑10R) expression in peripheral blood from patients with systemic lupus erythematosus (SLE). A total of 56 patients with SLE and 35 healthy individuals were recruited to the present study. The SLE disease activity index (SLEDAI) was calculated, and other laboratory parameters were measured. Peripheral blood was collected from all participants. The frequency of CD19+CD24highCD38high Bregs and IL‑10R+ expression on circulating lymphocytes was examined by flow cytometry. The serum levels of IL‑10 and TGF‑β were measured using enzyme‑linked immunosorbent assay. The associations between these measurements and SLEDAI or other laboratory parameters were analyzed by correlation analysis. The percentage of CD19+CD24highCD38high Bregs and the serum levels of IL‑10 were significantly increased, whereas the expression of IL‑10R on circulating lymphocytes was markedly reduced in patients with SLE compared with in healthy controls. The serum levels of TGF‑β1 were not markedly different between the groups. In addition, these factors were correlated with other SLE laboratory parameters, and inter‑correlations were presented with different degrees of significance. The percentage of CD19+CD24highCD38high Bregs was positively correlated with the percentage of IL‑10R+ lymphocytes, mean fluorescence intensity (MFI) of IL‑10R+ lymphocytes and serum IL‑10 levels. In addition, the percentage of IL‑10R+ lymphocytes was positively correlated with its expression level (MFI), whereas serum TGF‑β1 levels were negatively correlated with serum IL‑10 levels. The present results indicated that expansion of CD19+CD24highCD38high Bregs, upregulation of IL‑10 and deficient lymphocyte‑associated IL‑10R may serve as novel SLE biomarkers. It may be hypothesized that deficient IL‑10R expression results in compensatory enhanced IL‑10 expression, expansion of Bregs, and/or compromised Breg and IL‑10 functions, thus contributing to SLE development. Therefore, targeting the 'Bregs/IL‑10/IL‑10R' system may provide a novel therapeutic approach for the treatment of SLE.