Cellular localization of human herpesvirus 8 in nonneoplastic lymphadenopathies and chronic interstitial pneumonitis by in situ polymerase chain reaction studies

Objectives: To study the cellular localization of human herpesvirus 8 (HHV- 8) in rare cases of HHV-8 infection from Italy that are associated neither with human immunodeficiency virus (HIV) infection nor Kaposi's sarcoma (KS) . Methods: The presence and distribution of HHV-8-infected cells was investig ated by direct in situ polymerase chain reaction (PCR) in the lymph node ti ssues from 2 patients with reactive lymphadenopathies with florid follicula r hyperplasia and increased vascularity and in the lung tissue from 1 patie nt with chronic interstitial pneumonitis. Results: HHV-8 was localized in lymphoid and monocyte-macrophage cells scat tered in the interfollicular regions of both lymph nodes but not in endothe lial cells. In the lung tissue, HHV-8 was found in the inflammatory cells i nfiltrating the interalveolar interstitium, in endothelial cells of the pul monary vasculature, and in rare pneumocytes. Conclusions: HHV-8 can infect nonneoplastic lymph nodes of immunocompetent subjects, and the distribution of infected cells outside of the germinal ce nters resembles that of Epstein-Barr virus (EBV)-infected cells in the lymp h nodes in the course of infectious mononucleosis. Endothelial cells and pn eumocytes may be a target of HHV-8 infection out of the KS setting, at leas t in the presence of a chronic inflammatory process.