[Aging of the immunosystem and its significance for tumor genesis (author's transl)]

Age-related decline in immune function starts at the time of sexual maturity with the involution of the thymic cortex. Except for the marked atrophy of the thymus, there are little changes in younger and middle years. Immune aging becomes more prominent at the end of the sixth decade of life particularly by a progressive decrease of thymus-dependent immunity: functional deterioration of T lymphocytes subpopulations results in qualitative and quantitative changes of the cellular and the humoral immune response. According to the with modifications still acceptable concept of "immunological surveillance", immune deficiency favours the appearance of certain malignances. There are indications that age-related disturbancies in the network of immunological interactions may--in combination with the influence of carcinogens and other factors--contribute to the genesis and the spreading of tumors.