Abstract
The histopathological appearances of the thymus, lymph nodes, spleen, and gut-associated lymphoid tissue (tonsil, Peyer's patches, and appendix) in cases of the combined immunity-deficiency syndrome are presented. The appearance of tissues remaining after foetal thymic transplants and the effects of such transplants on the morphology of lymph nodes are also discussed. Although thymic appearances are remarkably constant the picture in the lymph nodes and spleen may vary considerably. The tonsils, Peyer's patches, and appendix appear to constitute one lymphoid organ in man, at least with regard to the developmental arrest that may occur in this syndrome.