Objectives: This study examines small intestinal absorption-permeability, intestinal inflammation and ileal structure and function in HIV-positive male homosexuals.
Methods: Thirty HIV-seropositive male homosexuals at various stages of disease underwent intestinal absorption permeability and 111indium leukocyte studies (for quantification of intestinal inflammation). Twenty-six men with AIDS had a dual radioisotopic ileal function test (whole body retention of tauro 23-[75Se]-selena 25-homocholic acid and 58cobalt-labelled cyanocobalamine), and 17 underwent ileocolonoscopy with terminal ileal biopsy.
Results: Well, HIV-infected, subjects had normal intestinal absorption-permeability, but both functions were impaired upon the development of AIDS. The median faecal excretion of 111indium in well patients (0.66%) did not differ significantly (P > 0.5) from controls (0.46%), but subjects with AIDS who were well or who had diarrhoea had significant (P < 0.005) intestinal inflammation (1.33% and 2.18%, respectively). The median 7-day retention of tauro 23-[75Se]-selena 25-homocholic acid in well patients with AIDS (38.9%) did not differ significantly (P > 0.2) from controls (39.3%), whereas the absorption of 58cobalt-labelled cyanocobalamine was significantly (P < 0.05) lower than controls (32.1% and 59.4%). Patients with AIDS-diarrhoea had significant (P < 0.001) malabsorption of both the bile acid (7.7%) and vitamin B12 (8.9%) which was more severe than in Crohn's ileitis (14.2% and 30.3%, respectively). Morphometric analyses of ileal biopsies were unremarkable in AIDS.
Conclusions: These studies demonstrate a low-grade enteropathy in patients with AIDS, severe ileal malabsorption in patients with AIDS diarrhoea and relatively minor ileal morphologic changes. Malabsorption of bile acids may play a pathogenic role in patients with AIDS and diarrhoea.