[Features of therapy of hematologic diseases in old age. 3. Features in the occurrence and clinical course of aplastic and neoplastic diseases of the blood].

The development and course of blood diseases in the aged often are determined by two factors: The first is the disturbance of the immune system based on a defective interaction between the T- and B-cell system. These are due to the involution of the thymus gland accompanied by reduced incretion of thymus hormones. The second factor consists in a regressive alteration of a "haemopoietic inductive micro-environment (Trentin), which has its morphological substrate in the circulatory system and the stroma of the bone marrow. Both factors lead to atrophic or diminished recovery of the bone marrow. Specific therapeutic problems are presented on the basis of several selected disease entities. Anaemias, cytopenias, the myeloproliferative syndrome and the lymphomas of low malignancy as well as the paraproteinaemias reveal the importance of the above-mentioned factors not only for the pathogenesis and the course but also for the treatment of these conditions in old age.