Detection and localization of HIV RNA and TNF mRNA in rectal biopsies from patients with AIDS.

The objective of this study was to compare the localization of cells containing human immunodeficiency virus (HIV) RNA and tumor necrosis factor (TNF)-alpha mRNA in rectal mucosa by RNA in-situ hybridization in a retrospective analysis of archived rectal biopsy specimens. RNA in-situ hybridization studies were performed in 27 HIV-seropositive individuals and seven controls, using antisense and sense 35S-labeled riboprobes. The detection and localization of positive cells were compared. HIV was RNA detected in 44% of biopsies, while TNF-alpha mRNA detected in 22%. TNF mRNA was found in biopsies from patients with and without opportunistic infections. All cells expressing TNF-alpha mRNA and most of the cells expressing HIV RNA were found in close proximity to the epithelial surface. The content of an HIV-associated protein, p24, in mucosal homogenates, determined by a quantitative ELISA technique was significantly higher in the subgroup of patients with positive in situ hybridization studies for TNF-alpha mRNA than in the subgroup with negative studies. The colocalization of TNF-alpha mRNA and HIV RNA immediately beneath the epithelium suggests a specific relationship between them, as well as a possible relationship to a luminal factor.