Diagnosis-independent loss of T-cell costimulatory molecules in individuals with cytomegalovirus infection

Major depressive disorder (MDD) is associated with physiological changes commonly observed with increasing age, such as inflammation and impaired immune function. Age-related impaired adaptive immunity is characterized by the loss of naive T-cells and the reciprocal accumulation of memory T-cells together with the loss of T-cell co-stimulatory molecules. Additionally, the presence and activity of cytomegalovirus (CMV) alters the architecture of the T-cell compartment in a manner consistent with premature aging. Because CMV is also thought to reactivate with psychological stress, this study tested whether MDD influences age-related phenotypes of T-cell populations in the context of CMV infection in young and middle-aged adults. Morning blood samples from volunteers with a DSM-IV diagnosis of MDD (n=98, mean age(SD)=36(10) years, 74.5% female, 57.1% CMV+) and comparison controls (n=98, mean age(SD)=34(10) years, 68.4% female, 51.0% CMV+) were evaluated for CMV IgG antibody status and the distribution of late differentiated (CD27-CD28-) cells within CD4+ and CD8+ T-cell subsets, i.e. naive (CCR7+CD45RA+), effector memory (EM, CCR7-CD45RA-), central memory (CM, CCR7+CD45RA-) and effector memory cells re-expressing CD45RA (EMRA, CCR7-CD45RA+). Mixed linear regression models controlling for age, sex, ethnicity and flow cytometry batch showed that CMV seropositivity was associated with a reduction in naive T-cells, expansion of EMRA T-cells, and a greater percent distribution of CD27-CD28- cells within CD4+ and CD8+ memory T-cell subsets (p's&nbsp