PHENOTYPIC VARIATIONS AND SWITCHES IN HIV ISOLATED FROM THE BLOOD ANDTHE GASTROINTESTINAL TISSUES OF PATIENTS WITH HIV-1 INFECTION

The objective of this study was to determine the initial and subsequen t phenotypes of HIV-1 isolated from the blood, duodenal, and colonic b iopsies of 51 HIV-1 positive patients followed prospectively over 2 ye ars. Blood and tissues were cocultured with stimulated peripheral bloo d monocytes, and HIV was analysed for phenotypic expression of syncyti a-induction (SI). A total of 45/51 patients had HIV-1 isolated from th e blood and 35/51 had HIV isolated from gastrointestinal tract. In 12/ 45 patients SI-HIV-1 was isolated from the blood. In 6/12 patients the blood phenotype reverted to the NSI phenotype. SI phenotypes were als o isolated from the colon and duodenum of 8/35 patients and reversion from SI to NSI virus phenotype was again observed in gut tissue of 3/8 patients. These results show that gastrointestinal tissues can harbor SI HIV phenotype. Discordant phenotypes can be found in tissue and bl ood of late-stage patients. Reversion of phenotypic SI expression to N SI may occur in patients receiving monotherapy as antiretroviral treat ment. These results suggest that gastrointestinal tissues may act as a separate and distinct site involved in HIV replication and its associ ated pathogenesis. (C) 1997 Wiley-Liss, Inc.