Objective To investigate the effect of common immunosuppressants on the follicular regulatory T cells (Tfr cells) and regulatory B cells (Breg cells). Methods Peripheral blood samples were collected from 6 healthy volunteers (5 mL per case).The lymphocytes were isolated by human lymphocyte isolation solution and cultured.The cells were divided into the control group (without supplement of immunosuppressants), ciclosporin group (250 ng/mL), tacrolimus group (10 ng/mL) and sirolimus group (10 ng/mL).The cells were stimulated with corresponding immunosuppressants for 48 h, respectively.The proportion of Breg and Tfr cells in the lymphocytes in each group was detected by flow cytometry.The content of interleukin (IL)-21 in the supernatants of each group was detected by enzyme-linked immunosorbent assay (ELISA). Results Compared with the control group, the proportion of Breg cells in the lymphocytes in the ciclosporin, tacrolimus and sirolimus groups was all significantly increased (all P < 0.05).In the ciclosporin group and tacrolimus group, the proportion of Tfr cells in the lymphocytes was both significantly elevated (both P < 0.05), whereas the proportion of Tfr cells in the lymphocytes in the sirolimus group was significantly decreased (P < 0.05).ELISA demonstrated that compared with the control group, the IL-21 content in the supernatants in the ciclosporin and tacrolimus groups was both significantly decreased (both P < 0.05).Use of sirolimus exerted no significant effect upon the secretion of IL-21 (P > 0.05). Conclusions Ciclosporin and tacrolimus can inhibit the immune response of B cells.
