Immune Biomarkers Predictive of Respiratory Viral Infection in Elderly Nursing Home Residents

These data helped to determine whether immune phenotypes associated with immunosenescence predicted risk of respiratory viral infection in elderly nursing home residents. To this end, peripheral blood mononuclear cells (PBMCs) were obtained and analysed by flow cytometry for T-regs, CD4+ and CD8+ T-cell subsets (naive [CCR7+CD45RA+], terminally differentiated [CCR7-CD45RA+] and senescent [CD28-CD57+]) and CMV-reactive CD4+ and CD8+ T-cells. We hypothesized that the following immune phenotypes associated with immunosenescence would be associated with increased risk of infection: low CD4+ and CD8+ naïve T-cells and high CD4+ and CD8+ terminally differentiated and senescent T-cells as well as high CMV-reactive CD4+ and CD8+ T-cells and high T-regs. Low was defined as immune phenotypes in the first quartile of the distribution and high was defined as immune phenotypes in the fourth quartile of the distribution. Nasopharyngeal swabs were obtained and tested for viruses in symptomatic residents. Models were adjusted for age, sex and frailty.