[Immune defect diseases in childhood].

The immune reactions of man may be subdivided into two main types, the antibody-bound and the cell-bound immunity. The effect of these two systems is realised by two different lymphocyte populations: T- and B-cells, which may show isolated or combined congenital defects and are known as primary immune defects. Antibody deficiency diseases are the by far most frequent congenital diseases. Concerning the frequency the combined and cellular immune defects follow. At present the diagnostic possibilities are already largely developed. Immune defect diseases have much contributed to the understanding of the normal immune reactions. Though these diseases also nowadays still have an extremely bad prognosis, there exists already for some forms a therapy in form of the transplantation of bone marrow, which is able to restore the defect immune system.