The additional RTX treatment had no effect on the Tcell phenotype. Although tacrolimus, MMF, and steroids mainly target T-cell activation, proliferation, and differentiation, we found that treatment with a combination of tacrolimus, MMF, and steroids, induced only marginal changes in the peripheral T-cell phenotype. These changes were mainly present within the first 6 months after transplantation, which suggests a role for MMF, as this drug was discontinued at 6 months after transplantation. Ex vivo, the T cells collected from patients treated with triple immunosuppressive therapy were functional, suggesting that they are only suppressed when the drug is present. In addition, we found that the ratio between CD4+ central memory and TREGS was increased under triple drug immunosuppressive therapy. Concomitantly, we observed a relative increase of CXCR3+ and CCR6+ CD4+ T cells, chemokine receptors associated with memory or activated Th1 and Th17 cells, respectively. This expression enables them to migrate toward inflammatory sites that express their cognate chemokines, such as observed in the graft during rejection and on activated human primary tubular epithelial cells. With respect to B cells, mycophenolic acid, but not tacrolimus, has been shown to inhibit the proliferation and immunoglobulin production in vitro. However, in patients with systemic lupus erythematosus who were treated with MMF, the Staurosporine PKC inhibitor number and phenotype of B cells were similar to that in controls without immunosuppressive therapy. In our cohort, discontinuation of MMF at 6 months after transplantation resulted in a relative increase of virgin naive Bm1 cells, while naive Bm2 cells were decreased compared to pre-transplant levels. Transitional Bm2 cells remained low up to 24 months after transplantation, suggesting that their development is mainly suppressed by treatment with tacrolimus and/or steroids. Finally, following the discontinuation of MMF, the percentage of memory B cells became comparable to levels before transplantation. Steroids were also found to have clear effects on B cells; ex vivo immunoglobulin production by PBMC was decreased during treatment with a high dose of prednisolone while a lower dose resulted in an increased production after stimulation. Others have described that steroids have an effect on B-cell activation, while proliferation and activation are less affected. Under combined treatment with tacrolimus, MMF, and steroids, our renal transplant recipients had a more memory-like B-cell phenotype compared to before transplantation. This relative increase of memory B cells was also found in a patient cohort treated with cyclosporine, MMF, steroids, and an anti-CD25 monoclonal antibody. The observed memory-like B-cell phenotype was accompanied by an increased percentage of CD80+ and CD95+ B cells, which may be explained by the preferential expression of these molecules on memory-like B cells. Adding a single dose of RTX to the combination of tacrolimus, MMF, and steroids in our patients indeed resulted in a long lasting B-cell depletion in peripheral blood.