Switch from cyclosporine A to tacrolimus in renal transplant recipients: impact on Th1, Th2, and monokine responses.

We showed previously that pretransplant CD4 helper defects and low in-vitro IL-10 responses predict a low risk of acute kidney graft rejection. To compare the effect of tacrolimus (Tacr) and cyclosporine A (CsA) on the humoral immune response we assessed T helper function, B cell/monocyte responses and in-vitro cytokine responses (TNF-alpha, GM-CSF, IL-1 beta, IL-2, IL-4, IL-6, IL-10) in 20 renal transplant recipients before and 3 months after they were switched from CsA to Tacr because of hyperlipoproteinemia, hirsutism, or gum hyperplasia. T helper function was assessed using a PWM-driven allogeneic coculture system of patient T cells together with control B cells. B cell/monocyte responses were determined using a PWM-stimulated allogeneic coculture system, SAC I-stimulated B-cell cultures and LPS-stimulated monocyte cultures. Immunoglobulin-secreting cell (ISC) responses were assessed in a reverse hemolytic plaque assay, and ELISA were used to determine cytokine secretion. Treatment with Tacr resulted in a decreased expression of costimulatory ligands and adhesion molecules (T cells: CD40L, p < 0.05; CD28 and CD54, p < or = 0.01; B cells: CD25, p = 0.05; CD40, p < 0.001; monocytes: CD40, p < 0.05), which coincided with decreased PHA-stimulated T cell IL-2 responses (398 +/- 153 versus 43 +/- 15 pg/ml, p < 0.05), impaired CD4 helper activity (117% +/- 22% versus 73% +/- 19%, p < 0.05) and increased CD4 suppressor activity (-120% +/- 28% versus -18% +/- 27%, p = 0.02). We observed enhanced CD4 IL-10 responses (p < 0.01) and LPS-stimulated monocyte responses (TNF-alpha, IL-1 beta, and IL-6, p < 0.005; IL-10, p < 0.05), indicating an increased humoral immune responsiveness under treatment with tacrolimus. Our data show that switching of immunosuppressive therapy from CsA to tacrolimus results in suppression of costimulatory ligands, adhesion molecules, Th1 responses and CD4 helper activity. However, enhanced humoral immune responses, Th2 and monokine responses, might have a negative impact on long-term graft function.