Objective: As HIV infection most commonly occurs via a mucosal surface, and as gastrointestinal symptoms are very frequent among HIV-infected patients, we investigated the functional properties of residual lymphocytes in the duodenal mucosa from HIV-infected individuals.
Design: Duodenal biopsies and blood samples were obtained from 19 HIV-infected patients [Centers for Disease Control and Prevention (CDC) stage III] and from 19 controls.
Methods: Phenotypic analysis of lymphocytes was performed by flow cytometry and/or immunocytochemistry. Interferon gamma (IFN-gamma), interleukin (IL) 4 and immunoglobulin secretions were analysed by enzyme-linked immunospot techniques. The phenotype of cytokine-producing cells was analysed by flow cytometry.
Results: The proportions of duodenal T lymphocytes from HIV-infected patients spontaneously secreting IFN-gamma or IL-4 were not lower than those from healthy controls. In patients with a high intestinal mucosal viral load, they were higher than in controls (P < 0.05). The proportions of immunoglobulin-secreting cells were significantly raised in HIV-infected patients for the three main isotypes.
Conclusions: T- and B-cell populations of the intestinal mucosa remain functional or are even activated in patients with AIDS, even when the numbers of both mucosal and circulating CD4+ lymphocytes are strongly decreased.