Comparison between serum interleukin-2 concentrations in healthy adult and elderly subjects

The serum interleukin-2 (IL-2) concentrations were evaluated in healthy elderly patients, enrolled under the SENIEUR protocol, and healthy adult controls. The aim of the study was to ascertain whether the reduced immune response, described during aging, is linked to deficient production of IL-2 or to its receptorial deficit, or if the reduced serum IL-2 concentrations observed during aging can be used as a biological immunodeficiency marker. The results obtained did not show any significant differences between the study groups, even if mean values were slightly decreased in the elderly group, as compared to the adult one. This finding does not justify the age-dependent deficiency of the immune response, i.e., to explain this condition, one needs another pathogenetic hypothesis. It is suggested that one such hypothesis could be the alteration of IL-2 receptors which undergo major cleavage and minor re-expression in the elderly, causing this way some receptorial changes with consequent reduction of T-helper activation.