Effect of everolimus‐based drug regimens on CMV‐specific T‐cell functionality after renal transplantation: 12‐month ATHENA subcohort‐study results

Post-transplant cytomegalovirus (CMV) infections and increased viral replication are associated with CMV-specific T-cell anergy. In the ATHENA-study, de-novo everolimus (EVR) with reduced-exposure tacrolimus (TAC) or cyclosporine (CyA) showed significant benefit in preventing CMV infections in renal transplant recipients as compared to standard TAC + mycophenolic acid (MPA). However, immunomodulatory mechanisms for this effect remain largely unknown. Ninety patients from the ATHENA-study completing the 12-month visit on-treatment (EVR + TAC n = 28; EVR + CyA n = 19; MPA + TAC n = 43) were included in a posthoc analysis. Total lymphocyte subpopulations were quantified. CMV-specific CD4 T cells were determined after stimulation with CMV-antigen, and cytokine-profiles and various T-cell anergy markers were analyzed using flow cytometry. While 25.6% of MPA + TAC-treated patients had CMV-infections, no such events were reported in EVR-treated patients. Absolute numbers of lymphocyte subpopulations were comparable between arms, whereas the percentage of regulatory T cells was significantly higher with EVR + CyA versus MPA + TAC (p = 0.019). Despite similar percentages of CMV-specific T cells, their median expression of CTLA-4 and PD-1 was lower with EVR + TAC (p