[Histological changes in the lymph nodes during immune stimulation reactions].

The stimulation of the cellular and humoral immune reactions is described, as well as the different cellular types implicated (B and T lymphocytes, their subsets and derived cells, and mononuclear cells of the phagocytic system). The classification of these various cells, using immunolabeling the "back-up" cells and the so-called immune-accessory cells (dendritic and interdigital reticular cells) is also shown. The aspects of lymphatic circulation and intralymphatic blood circulation are then discussed. Findly, the various elementary modifications which appear during these immune reactions are studied: some result from the action of the humoral immunity (follicular hyperplasia, immunoblastic hyperplasia and plasmocytosis), and others from the stimulation of cellular immunity (hyperplasia of the deep cortex). These modifications may be variably associated with plasmacytoid cell hyperplasia, various sinusal reactions (chronic catarrh, macrophagic histiocytosis - some-times erythrophagocytic, and B-lymphocytosis), and histiocytic, epithelioid, tuberculoid or abscessed granulomatous reactions. the diagnosis and classification of these elementary lesions allow the definition of the histopathological type, thus permitting the orientation towards a certain etiology.