Different effect of 1,25-dihydroxyvitamin D3 on replication of Mycobacterium avium in monocyte-derived macrophages from human immunodeficiency virus-infected subjects and healthy controls.

Mycobacterium avium complex (MAC) is the most common cause of disseminated bacterial infection in patients with acquired immune deficiency syndrome (AIDS) and macrophage dysfunction is important both in the pathogenesis of AIDS- and MAC-infection. 1,25-Dihydroxyvitamin D3 (1,25D), the active metabolite of vitamin D, has a number of effects on cell types of the immune system including monocytes/macrophages. The present study was designed to investigate whether 1,25D supplementation in vitro could modulate MAC replication in macrophages from HIV-infected patients. It was therefore of particular interest to examine whether the effect of 1,25D differs between cells from HIV-infected patients and healthy control subjects. After 3 and 7 days of infection, 1,25D supplementation increased numbers of bacteria in cells from control subjects. In contrast, there was no change or even a decrease in numbers of bacteria in cells from HIV-infected patients. These findings suggest that HIV infection may significantly modulate the macrophage response to 1,25D stimulation, and that 1,25D may have inhibitory effects on MAC replication in macrophages from HIV-infected patients.