Immune reactivity in aging-autologous mixed lymphocyte responses.

The level of activity in the autologous mixed lymphocyte reaction (AMLR) was studied in populations of young and old subjects. AMLR activity was reduced in the older age group. A subpopulation of the older age group who had Alzheimer's disease was shown to have the lowest AMLR values. Within this group, those with a history indicating a more rapid development of CNS-related disability from senescence showed the weakest AMLR responses. The AMLR values correlated neither with sex, nutritional status nor history of infections. This impairment of a central regulating immune reaction may be a significant variable in manifestations of the aging process.