Reversibility of age associated NK defect by endocrinological and/or nutritional intervention.

Several abnormalities arise at the level of NK cell function in both rodents and humans with increasing age. The age-related changes are not irreversible alterations since they can be reversed either by endocrinological or nutritional approaches, suggesting that age-related microenvironmental changes may play a relevant role in the age-related immune deterioration. Whether endocrine and nutritional factors have an additive effect or act through the same intracellular mechanisms remains to be established, though the first possibility seems more likely since the action of TSH and thyroid hormones is specifically directed towards lymphokine-boosted NK activity, while AL are able to prevent age-associated defect of basal NK cytotoxicity.