CYTOKINE PRODUCTION PATHWAY IN THE ELDERLY

It is well known that aging is associated with various alterations in lymphoid cell functions, particularly with a progressive decline in im mune responsiveness to exogenous antigens and increasing incidence of autoimmune phenomena. Many studies have been focused on the mechanisms of the immunologic features of aging. This review describes our resul ts of studies performed to determine the influence of age on the capac ity to produce interleukin-2 (IL-2), interferon-gamma (IFN-gamma), int erleukin-4 (IL-4), interleukin-5 (IL-5), interleukin-6 (IL-6) and tumo r necrosis factor (TNF). Mitogen-stimulated cultures of mononuclear ce lls (MNC) from human beings were assessed for cytokine-producing capac ity. A significant decrease in IFN-gamma and IL-2 production by MNC cu ltures from elderly individuals was observed. No significant differenc e was instead observed between cultures from elderly individuals and t hose from young ones as regards TNF-alpha, IL-4 and IL-6 production. M itogen or antigen-stimulated cultures of MNC from aged mice also displ ayed a significant decrease in IFN-gamma and IL-2 production as well a s TNF-beta. Instead IL-4 and IL-5 production significantly increased i n these cultures. We suggest that this imbalanced cytokine production may well account for the pattern of immune response which may be obser ved in the elderly, i.e. a normal or increased humoral response (inclu ding autoimmune responses) in face of a low T cell immune responsivene ss.