Immunosenescence is both functional/adaptive and dysfunctional/maladaptive

Abstract

Alterations in the immune system with aging are considered to underlie many age-related diseases. However, many elderly individuals remain healthy until even a very advanced age. There is also an increase in numbers of centenarians and their apparent fitness. We should therefore change our unilaterally detrimental consideration of age-related immune changes. Recent data taking into consideration the immunobiography concept may allow for meaningful distinctions among various aging trajectories. This implies that the aging immune system has a homeodynamic characteristic balanced between adaptive and maladaptive aspects. The survival and health of an individual depends from the equilibrium of this balance. In this article, we highlight which parts of the aging of the immune system may be considered adaptive in contrast to those that may be maladaptive.

Keywords: Adaptation; Centenarians; Immunosenescence; Immunosuppressive mechanisms; Inflammaging; Maladaptation; Trained immunity.

Fig. 1.

The balance between the adaptive/maladaptive patterns of an individual’s aging immune system. Adaptive and maladaptive immune changes can be found simultaneously in the same individual and in the same arms of the immune response (innate or adaptive). Concurrent (also balanced or imbalanced) changes in other body systems will affect the immune system. Complex integrated immunobiography over time will determine which state (balanced/adapted or imbalanced/maladapted) will predominate and towards which destiny (resilience and longevity, or aging-related diseases, frailty and earlier death) the organism will be pushed