Aging is accompanied by the progressive modification and imbalance of the immune system function. Physical exercise can affect gene expression profiles of human white blood cells even after a single bout of exercise. However, it is not clear how the immune cells of elderly people can be responsive to the "exercise stimulus".

We evaluated the transcriptional profile of whole blood cells (WBCs) and compared baseline age-related signatures, and transcriptional changes produced by single bouts of exercise at different intensities. Experiments have been carried out on two groups of 10 healthy men of different age (50±5 and 70±5 yy) recruited locally. Both groups performed 30 min of constant workload cycling exercise corresponding to 80% and 60% of V'O2max. RNA-stabilized blood samples were obtained 30 min before and 1hr after each constant load tests. Gene expression of WBCs was evaluated using whole genome microarray expression analysis with Affymetrix Human Gene 1.0 ST arrays.

Results of differential expression analysis and Gene Set Enrichment Analysis highlighted age-related differences at the baseline related to innate immunity, stress response and cellular metabolic pathways. In both groups the exercise performed at different intensities brought about progressive and intensity-dependent signatures, and the observed patterns differed as a function of age. Several known gene pathways related to innate immunity, cytokine regulation, cellular metabolism, and cellular differentiation were modified.

Ageing alters gene expression profile of immunocompetent cells. The patterns of changes induced by a single bout of exercise are different between adults and elderly subjects.