The value of lymph node biopsy in patients with the acquired immunodeficiency syndrome (AIDS) and the AIDS-related complex (ARC): a morphological and immunohistochemical study of 90 cases

The morphological and immunohistochemical findings in lymph nodes of nine patients with the acquired immunodeficiency syndrome (AIDS) and 81 patients with the AIDS-related complex (ARC) are presented. Three basic histological patterns were observed: follicular hyperplasia (29 cases), mixed hyperplasia (49 cases) and lymphocyte depletion (12 cases). While the first two variants were detected in typical ARC patients, lymphocyte depletion was always associated with AIDS. Immunohistochemistry on frozen sections showed that the number of B-cells varied throughout the series, being higher in the follicular type and significantly lower in the lymphocyte depletion nodes. The content of T-lymphocytes of the helper/inducer (T4) phenotype was reduced in all instances; this reduction was more pronounced in the germinal centres in follicular hyperplasia, while it involved all compartments of the node in the mixed and lymphocyte depletion types. In contrast the cytotoxic/suppressor (T8) subset was increased in the follicular and mixed hyperplasias only. Partial disintegration of the dendritic network in at least some of the follicles could be demonstrated in all lymph nodes. In the follicular and mixed hyperplasias there was a high number of proliferating B-cells in the germinal centres. Our data indicate the usefulness of grading the changes occurring in lymph nodes of patients with ARC and AIDS, and allow speculation as to the pathophysiology of these conditions.