Cyclosporin A and tacrolimus reduce T‐cell polyfunctionality but not interferon‐γ responses directed at cytomegalovirus

Cytomegalovirus (CMV) ‐specific immunity is often estimated by the number of in vitro CMV antigen‐inducible interferon‐γ‐positive (IFN‐γ+) T cells. However, recent work indicates that simultaneous production of IFN‐γ, tumour necrosis factor‐α (TNF‐α) and interleukin‐2 (IL‐2) (referred to as ‘polyfunctionality’) is more relevant for anti‐viral protection. Here, we compared polyfunctionality of CMV‐specific T cells (pp65 and IE‐1 proteins) in 23 solid‐organ transplant patients and seven healthy controls by flow cytometry. The proportions of TNF‐α+/IFN‐γ+/IL‐2 cells among the activated cells were significantly reduced in transplant patients but not the frequencies of IFN‐γ+ CD8+ T cells. Immunosuppression reduces polyfunctionality, which reflects the increased infection risk in this patient group.