Immune deficiency, autoimmunity and aging

Immune deficiency states in man and animals have been observed at all ages---in the very young, in adult life and the very old. At all ages there appears to be a correlation between immune deficiency and propensity to produce autoantibodies and malignancy. Cellular replacement in immunologically deficient mice results in correction of immune function and slightly increased survival while selected hybridization produces dramatic increases in survival and a delayed onset of autoimmune symptoms. Aging is defined in terms of primary and secondary events where a hypothetic rate of decline of function, called optimum functional longevity, is arbitrarily assigned to the long-lived population. Optimal functional longevity is genetically based and controlled by a hypothetic longevity homeostasis gene complex which includes Ir genes and genes that control endocrine balance.