HIV-associated Waldeyer's ring lymphoid hyperplasias: Characterization of multinucleated giant cells and the role of Epstein-Barr virus

Lymphoid hyperplasia of Waldeyer's ring (WR) is an often-symptomatic compli cation of human immunodeficiency virus (HIV) infection. A characteristic bu t not well explained finding is the presence of multinucleated giant cells (MNGCs) adjacent to crypt or surface epithelium. To further elucidate the M NGCs and assess their relationship to HN and Epstein-Barr virus (EBV), 12 s pecimens from 11 HIV-positive patients were stained with. antibodies to HIV -1 p24, EBV (latent membrane protein, LMP-I), histiocytes (CD68), and other antigen-presenting cells: S-100 protein, the Langerhans cell (LC) marker C D1a, and the follicular dendritic cell (FDC) marker (CD21). Double immunofl uorescent staining to assess co-expression of p24 and cell-specific markers was performed and analyzed by laser-scanning confocal microscopy with 3-di mensional reconstruction. In situ hybridization for EBV-encoded small RNA ( EBER) was performed in all cases. Immunostains showed MNGCs labeled for p24 , S-100, and CD68, but not CD1a. In 1 case, rare MNGCs were CD21-positive. EBV LMP-1 was uniformly negative, although EBER-positive lymphocytes were s een by in situ hybridization in 9 of 12 specimens (numerous in only 3 speci mens). Double immunofluorescent staining showed co-localization of p24 with CD68 and S-100. Our results suggest that MNGCs are generally HIV-infected, EBV-negative, and most likely represent an unusual S-100-positive histiocy te subset (not LC or FDC). Their exact pathophysiologic role remains uncert ain. EBV does not appear to play a major role in the pathogenesis of WR lym phoid hyperplasias in HIV infection. Copyright (C) 1999 by W.B. Saunders Co mpany.