Department of Medical Microbiology and Immunology, University of California, Davis, California 95616, USA.
Gastrointestinal complications are commonly detected in advanced HIV infection. Recent findings suggest that gut-associated lymphoid tissue (GALT) is an early target of HIV and a rapid onset of the pathologic processes occur in GALT during early HIV infection that is not adequately reflected in the peripheral blood compartment. High levels of viral replication and dissemination in GALT lead to rapid and severe depletion of memory CD4+ T cells and result in immune activation and mucosal damage. Disruption of the integrity of the intestinal epithelial barrier also may occur during early HIV infection. Initiation of anti-HIV therapy resulted in incomplete suppression of viral replication and partial restoration of CD4+ T cells in GALT compared with peripheral blood. This coincided with the persistent immune activation and decreased levels of mucosal repair and regeneration. Disruption of the mucosal immune system and the epithelial barrier may impair mucosal defenses against HIV as well as other microbial pathogens and lead to HIV-associated enteropathy. Persistent viral replication in GALT may help maintain viral reservoirs. Evaluation of HIV replication and immune defenses in GALT may be valuable to determine the efficacy of anti-HIV therapeutics as well as vaccines.
