Role of cytomegalovirus in the T cell changes seen in elderly individuals

The effect of prior cytomegalovirus (CMV) infection on the immune system wa s evaluated in young and elderly volunteers. Prevalence of IgG antibodies t o CMV was higher in the elderly volunteers. In both age groups, there was a strong association with CMV seropositivity and increased number of CD28- C D4 or CD8 T cells, as well as with increased numbers of T cells expressing CD56 or DR. Although these changes have previously been reported to be age- related, they were independent of age when CMV serological status was taken into account. In contrast, both age group and CMV status were important de terminants of the total number of T cells, the number of CD8 T cells, and t he number of CD8 T cells expressing CD45RA or CD28. These findings indicate that prior infection with CMV, as reflected by CMV serological status, has important effects on T cell subsets and surface markers and must be consid ered whenever evaluating age-related changes in immunological parameters. ( C) 1999 Academic Press.