Excessive production of pro-inflammatory cytokines in immune aging. The aging process results in an increase in basal cytokine production by macrophages, dendritic cells, endothelial cells and fibroblasts. Whereas young cells require stimulation to secrete cytokines and thus are closely controlled, old cells release cytokines spontaneously. The elevation in spontaneous cytokine production in the absence of specific stimulation results in a pro-inflammatory environment in which tissues are constantly 'primed' by cytokines. Chronic cytokine triggering may result in the generation of neoantigens and may contribute to the exhaustion of reserve pools supplying T cells and B cells. There is a corresponding decline in the ability of the immune system to mount a robust response as chronic cytokine exposure may alter the rheostat of cellular responsiveness.