Transitional B Cells Predominantly Reconstituted After a Desensitization Therapy Using Rituximab Before Kidney Transplantation

The role of B cells in graft rejection and tolerance has aroused great interest. We previously reported that rituximab (RIT) induction prior to kidney transplantation (KTx) reduced the incidence rate of chronic rejection. Here, we performed a cross sectional investigation to determine the characteristics of B cells after RIT induction for KTx. We sampled blood from 29 patients with (N = 16) and without (N = 13) RIT induction 3 to 18 months after KTx. In the RIT group, the majority of repopulating B cells was the transitional type, while memory B cells were scarce. Although transitional B cells are believed to have immune‐regulatory functions by producing IL‐10, transcriptional levels of IL‐10 in the peripheral blood mononuclear cells were similar in both groups. In contrast, transcription levels of BAFF‐receptor relatively increased in patients with RIT induction. In conclusion, BAFF‐receptor expressing highly proliferating transitional B cell was the major subset after RIT induction for KTx.