Human immunodeficiency virus (HIV) envelope and core proteins in CNS tissues of patients with the acquired immune deficiency syndrome (AIDS).

Frequency, cellular tropism and relation to pathology of productive infection with human immunodeficiency virus (HIV) in human central nervous system (CNS) were studied. Serial sections of formol-fixed and paraffin-embedded CNS tissues from 70 patients (69 with acquired immune deficiency syndrome, AIDS) were immunolabeled with monoclonal antibodies against HIV antigens (Ags) p17, p24, and gp41. Additional and double (immuno)stains were used to identify cell types and opportunistic infectious agents. HIV Ags were detected in 52 cases; they were restricted to cells with characteristics of microglia or macrophages. Anti-gp41, anti-p24, and anti-p17 labeled 50, 33, and 15 cases, respectively. Immunoreactivity for core proteins predominated in mature macrophages and microglia of fully developed lesions; additional immunoreactivity for gp41 was seen in microglia adjacent to, or unassociated with, histopathological lesions. Multifocal and/or diffuse lesions previously suggested as HIV induced because of characteristic histopathology, consistently contained large numbers of cells with HIV Ags (33 cases), confirming their HIV specificity. Isolated labeled microglia without associated pathology, found in seven brains, presumably represent the earliest stage of productive CNS infection by HIV. Lesions of opportunistic infections contained no (34 cases), few (16 cases), or many (4 cases) cells with HIV Ags. These data do not suggest transactivation of local HIV production by opportunistic agents as a frequent event in vivo. Development of specific HIV histopathology appears correlated with the number of productively infected cells.