[Angioimmunoblastic lymphadenopathy: ultrastructural study of lymph nodes. Possible relationship with Epstein-Barr Virus (EBV) (author's transl)].

Angioimmunoblastic lymphadenopathy (AIL) has been clinically and histopathologically described by several authors since 1972, but only a few papers have analyzed the morphological aspects of the lymph nodes as observed by using electron microscopy. In the past three years, we happened to see in the Curie Institute two typical cases of AIL, both of whose clinical and immunological data are briefly reported in this paper. We describe some peculiar patterns observed on the lymph nodes during the acute phase of the disease, by examination of semithin sections and electron-microscopic preparations. As have many others, we found strong diffuse B-lymphocyte proliferation, but we must emphasize that many plasmocytes had an obvious defect in cell maturation, but no monomorphous defect. We noted that the predominant postcapillary venules had hypertrophied endothelial and perithelial cells, and multilayering basal lamina. We found some unusual features such as lymphocyte and/or plasmocyte phagocytosis by macrophages, or the atypical aspect of eosinophilic granulations. Finally, in the cytoplasm of a few transformed lymphocytes we detected some viral-like particles resembling herpes virus. Whether this last finding may have been related to the pathogeny of AIL could not be resolved by using morphological techniques. In the second part of this paper, we discuss the etiology of the disease, taking in account our clinical, immunological, and morphological observations. The possible relation of AIL to infectious mononucleosis, and the hypothetical role of Epstein-Barr virus are discussed.