Expression profiling of immune-associated genes in peripheral blood mononuclear cells reveals baseline differences in co-stimulatory signalling between nonagenarians and younger controls: the vitality 90+ study

The human immune system, especially the adaptive branch, substantially declines with ageing. Several distinct immunosenescent events have already been described, yet data regarding to age-associated baseline alterations in immune cell function is limited. Therefore, by using the TaqMan Human Immune Arrays we conducted a preliminary gene expression profiling of immune-related genes in the peripheral blood mononuclear cells of young individuals (aged 22-37 years, n = 13) and nonagenarians (n = 12), the latter being part of the Vitality 90+ Study. We also analysed the correlations between significantly regulated genes. The results revealed a significantly decreased expression of CCR7, CD19, CD28, CD40LG, ICOS, IL4, IL6 and LTA as well as significantly increased expression of FN1 in the nonagenarians as compared to the controls. Significant direct correlations were observed between the expression of CCR7 and CD19, CCR7 and ICOS, ICOS and CD19, ICOS and CD40LG, as well as CD40LG and CD28 in the nonagenarians but not in the controls. These results suggest that the key players of adaptive immunity i.e. the factors required for full lymphocyte activation are markedly and coordinately down-modulated in the very old individuals. Further research is, however, required to establish the relationship between these changes and the mechanisms of immunosenescence.