[Immunity in the aged].

The function of most organs decline in function of ageing and the immune system forms no exception. It has been shown that atrophy of the thymus plays a central role in these diminished immune reactions and also in two other immunogerontological phenomena: auto-antibodies and idiopathic paraproteinaemia. Already at this stage of our knowledge the information is of practical value in geriatric medicine. Immunological research can also contribute to our understanding of diseases of ageing and further our insight into the process of ageing itself.