Association of detectable cytomegalovirus (CMV) DNA in monocytes rather than positive CMV IgG serology with elevated neopterin levels in community-dwelling older adults

In immunocompetent persons, cytomegalovirus (CMV) is thought to persist primarily in monocytes and myeloid progenitor cells, establishing a chronic infection. In older adults, chronic CMV infection is typically diagnosed by a positive IgG serology. While many studies have shown CMV-specific T-cell expansion in CMV seropositive older individuals, significant heterogeneity has also been observed in this elderly population. In a study of 71 community-dwelling older adults, we assessed CMV viral DNA in peripheral monocytes by nested PCR and compared the relationships of detectable CMV DNA and IgG serology with serum levels of neopterin, a marker for monocyte/macrophage-mediated immune activation. The results showed that 52 (73.2%) participants were CMV seropositive, of whom 30 (57.5%) had detectable CMV DNA. CMV seropositive and seronegative participants did not differ in their neopterin levels, but individuals with detectable CMV DNA had higher neopterin than those without (10.6 ± 4.4 vs 8.0 ± 1.9 nM, respectively, p < .0001) adjusting for demographic and clinical covariates and interferon (IFN)-γ levels. In addition, there was no association between IgG titers and neopterin. These findings suggest that detection of CMV viral DNA in monocytes may be an informative tool to evaluate chronic CMV infection and its potential role in monocyte/macrophage-mediated immune activation in the elderly.

Research highlights
► About half of CMV seropositive older adults had detectable CMV DNA in monocytes.
► Neopterin was significantly higher in older persons with detectable CMV DNA.
► No association was observed between CMV seropositive or absolute CMV IgG titers.
► CMV DNA detection was informative in evaluating chronic CMV infection in seniors.
► Potential role of CMV in monocyte/macrophage mediated immune activation in elderly.