DETECTION OF CYTOMEGALOVIRUS DNA IN MONOCYTES CMV-SPECIFIC T CELLS AND IL-6 LEVELS IN OLDER ADULTS

摘要

Chronic cytomegalovirus (CMV) infection is believed to significantly contribute to T-cell immunosenescence and adverse health in older adults. A major barrier to advancement in this field has been that chronic CMV infection is diagnosed by anti-CMV IgG serology, a crude measure that merely indicates prior exposure to the virus and does not distinguish between past (resolved) or chronic (persistent) infections. We have optimized a nested PCR-based assay for qualitative detection of CMV DNA in the peripheral blood mononuclear cells (PBMCs). In this study, we evaluated 89 men and women InCHIANTI study participants (mean age=79, 65–96 years old). Among them, 36 were HLA-A2+ for whom CMV pp65-specific CD8+ T-cell frequencies were measured through class I tetramer analysis. The results showed that 56 of 89 participants (63%) had detectable monocytic CMV DNA while almost all (99%) were CMV seropositive. Those with detectable monocytic CMV DNA had significantly higher serum IL-6 levels than those without (1.81+1.5 vs 1.19+0.91 pg/ml, respectively, P=.01), regardless of anti-CMV IgG titers. Among 36 HLA-A2+ participants, those with detectable monocytic CMV DNA (n=20) had significantly higher CMV pp65-specific CD8+ T-cell frequency than those without (n=16, 3.65 ± 3.6% vs 0.86 ± 0.67%, respectively, P=.003). Taken together, these results suggest that detection of human CMV viral DNA in the PBMCs may be a better indicator than CMV seropositivity for increased IL-6 levels and CMV pp65-specific CD8+ T-cell expansion in older adults. Research is needed to further evaluate detection of monocytic CMV DNA as a valuable diagnostic tool of chronic CMV infection in older adults.