Frequency of regulatory B cells in adipose tissue and peripheral blood from individuals with overweight, obesity and normal-weight

•Regulatory B cells were diminished in adipose tissue from individuals with obesity.•Regulatory B cells were reduced in blood of individuals with overweight and obesity.•Augmented percentages of Th1/Th17 cells were observed in individuals with obesity. Regulatory B (Breg) cells have a critical role in adipose tissue homeostasis, and although subtypes of Breg cells have been described, their contribution during obesity is unclear. Therefore, the levels of regulatory B cells in adipose tissue and peripheral blood samples drawn from individuals with overweight, obesity, and normal-weight were evaluated. The percentages of Breg cells were analyzed by flow cytometry. The activity of Breg cells was assessed by measuring the release of IFN-γ in the supernatants of co-cultures of CD4+ T and regulatory B cells with an ELISA assay. The levels of IL-17 and IFN-γ produced by the CD4+ T cells were assessed using an ELISA assay. Diminished frequencies of Breg cells with phenotypes CD19+CD27+CD38High, CD19+CD24HighCD38High, and CD19+CD24HighCD38HighIL-10+ cells were observed in the blood samples from the individuals with overweight and obesity but not in the individuals with normal-weight. The production of IFN-γ in CD4+ T-cell cultures showed a decrease in the presence of Breg cells in individuals with obesity and normal-weight. We found fewer percentages of CD19+CD27+CD38High cells in the adipose tissue samples from individuals with overweight and obesity compared to individuals with normal-weight. In addition, elevated levels of IL-17 and IFN-γ in the supernatants of the cultures of CD4+ T cells from the individuals with obesity compared to the individuals with normal-weight were observed. The results suggest that individuals with obesity show increased levels of Th1/Th17 cytokines, which might be caused by the decreased frequency of regulatory B cells.