Setting: The National HIV Unit, Singapore.
Objective: To test whether zinc supplementation improves the immune response to tuberculosis in HIV-positive patients.
Design: A double-blind, randomised, placebo-controlled trial of 28 days of oral zinc sulphate (50 mg of elemental zinc) or placebo in stable adult HIV-positive patients receiving antiretroviral therapy with a CD4 count <200 cells/microl.
Methods: IFN-gamma response to mycobacterial antigen stimulation, CD4/8 cell count, lymphocyte subsets, T-cell receptor excision circle (TREC) levels and viral load were measured at baseline and day 28.
Results: Thirty-two patients received zinc and 34 placebo. There was no significant change in the IFN-gamma response to human PPD stimulation in the zinc or placebo groups (placebo baseline: 0.42 +/- 1.03, day 28: 0.84 +/- 1.21 IU/ml, zinc baseline: 1.26 +/- 2.41, day 28: 1.39 +/- 1.88 IU/ml, P = 0.31 between groups), nor any of the other mycobacterial antigens tested. There were no changes in absolute CD4/8 cell levels or other lymphocyte subsets, TREC or viral load. Baseline zinc levels were normal in 62/66 (93.9%) patients.
Conclusions: We found no evidence for recommending pharmacological supplementation with oral zinc in HIV-positive patients without zinc deficiency.