increased cytotoxic cd4+ t cells with reduced cytotoxic gene profile expression in cytomegalovirus reactivated kidney transplant patients

Cytotoxic cd4+ t cells eliminate human cytomegalovirus (hcmv)-infected cells through direct cytotoxic granules exocytosis. we aimed to evaluate the functional cytotoxic gene profile of cd4+ t cells alongside the frequency of the cytotoxic phenotype in renal transplant recipients with cytomegalovirus reactivation.blood samples were collected from twenty renal recipients with and without hcmv reactivation (hcmv+ and hcmv- groups) and ten healthy adults (control group). cd4+ t cells were isolated to assess the frequency of cytotoxic cd4+ t cells via cd107a surface staining using flow cytometry and to evaluate gene expression of perforin, granzyme b, runt-related transcription factor 3 (runx3), and eomesodermin (eomes) by quantitative pcr.the frequency of cd4+ cd107a+ t cells was higher in the hcmv+ group compared to the hcmv- group and significantly higher than in the control group (22.69 ± 3.47 vs 16.41 ± 2.24 and 11.60 ± 1.17, respectively). perforin gene levels were reduced in the hcmv+ group compared to the other two groups, while granzyme b gene levels were similar between hcmv+ and hcmv- groups but lower than in the control group (0.63 ± 1.24 vs 0.67 ± 2.27 and 1.00 ± 0.00, respectively).this study demonstrated an increased frequency of cytotoxic cd4+ t cells with potentially reduced functionality in kidney transplant patients with hcmv infection. it also suggests that these cells might employ other mechanisms, such as death receptor-mediated killing, or the production of other granules.