Abstract
Cytomegalovirus (CMV) is known to alter circulating effector memory or re-expressing CD45RA(+) (TemRA) T-cell numbers, but whether Epstein-Barr virus (EBV) does the same or this is amplified during a CMV and EBV co-infection is unclear. Immune cell numbers in blood of children and young, middle-aged, and senior adults (n = 336) were determined with flow cytometry, and additional multivariate linear regression, intra-group correlation, and cluster analyses were performed. Compared to non-infected controls, CMV-seropositive individuals from all age groups had more immune cell variance, and CMV(+) EBV(-) senior adults had more late-differentiated CD4(+) and CD8(+) TemRA and CD4(+) effector memory T-cells. EBV-seropositive children and young adults had a more equal immune cell composition than non-infected controls, and CMV(-) EBV(+) senior adults had more intermediate/late-differentiated CD4(+) TemRA and effector memory T-cells than non-infected controls. CMV and EBV co-infected young and middle-aged adults with an elevated BMI and anti-CMV antibody levels had a similar immune cell composition as senior adults, and CMV(+) EBV(+) middle-aged adults had more late-differentiated CD8(+) TemRA, effector memory, and HLA-DR(+) CD38(-) T-cells than CMV(+) EBV(-) controls. This study identified changes in T-cell numbers in CMV- or EBV-seropositive individuals and that some CMV and EBV co-infected young and middle-aged adults had an aging-related T-cell phenotype.