Morbidity does not influence the T-cell immune risk phenotype in the elderly: findings in the Swedish NONA Immune Study using sample selection protocols.

A critical issue in our understanding of ageing and the immune system refers to the health status of the population from which inferences are drawn. The commonly used SENIEUR protocol, selecting individuals representing 'normal ageing' has recently been under debate because a substantial amount of individuals with various health problems are excluded. The aim of the present study was to investigate the influence of morbidity on immune parameters and to evaluate the associations with the T-cell immune risk phenotype (IRP), related to cytomegalovirus (CMV) seropositivity by applying the SENIEUR protocol and the OCTO-Immune protocol in the unselected population based sample (n=138) of oldest-olds, participating in the Swedish NONA Immune Study. The SENIEUR protocol excluded over 90% of the sample whereas the OCTO-Immune protocol excluded almost 65% of the sample. Three independent groups, very healthy (SENIEUR), moderately healthy (OCTO-Immune) and frail (non-SENIEUR/non-OCTO-Immune) were created. Flow cytometry studies on lymphocyte sub-populations revealed no significant difference in CD4/CD8 ratio, CD3+CD4-CD8+, CD3+CD4+CD8-, CD8+CD57+CD28-, CD8+CD56+CD57- or CD8+CD56+CD57+ between the very healthy, moderately healthy and the frail subsamples. Our findings indicate that morbidity does not significantly influence the T-cell immune risk profile in the elderly, and we suggest the inclusion of broader samples in future immunogerontological studies.