Immune Risk Phenotypes and Associated Parameters in Very Old Humans: A Review of Findings in the Swedish NONA Immune Longitudinal Study

In the previous OCTO immune longitudinal study of free-living subjects >85 yr. selected for good health, we identified an Immune Risk Phenotype (IRP) associated with increased mortality. The IRP was characterised by high CD8+, low CD4+ T-cell counts and a poor T-cell proliferative response, inversion of the CD4/CD8 ratio and evidence of persistent cytomegalovirus infection. In the NONA immune longitudinal study the aim was to examine whether the same IRP parameters applied to a population-based sample aged 86–94 years who were not selected for very good health. More sophisticated analytical parameters were studied, as well as the role of inflammatory processes in relation to longevity. The immune panel included the analysis of T-cell subsets inflammatory markers, virus serology, cytokines, TCR clonotype mapping and functional and phenotypic analysis of virus-specific CD8+ cells by HLA/peptide multimers, in collaborations between participants of the EU funded T-CIA project.