Submitted to: Epidemiology and Infection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/7/2013
Publication Date: 7/1/2014
Citation: Kawai, K., Meydani, S.N., Urassa, W., Wu, D., Mugusi, F.M., Saathoff, E., Bosch, R.J., Villamor, E., Spiegelman, D., Fawzi, W.W. 2014. Micronutrient supplementation and T-cell mediated immune responses in patients with tuberculosis in Tanzania. Epidemiology and Infection. 142(7):1505-1509. DOI:10.1017/S0950268813002495. Interpretive Summary: Patients who have a pulmonary (lung) disease known as tuberculosis (TB) often suffer from poor diet and deficiencies of micronutrients (certain vitamins) in countries with limited resources. Recurrence of TB has been noted in the elderly of Western countries and is attributed to the decline in immune response with aging. Micronutrient deficiencies have been reported in a significant portion of older adults. We examined whether providing micronutrient supplements to pulmonary tuberculosis patients might improve their immune function in a human study conducted in Tanzania. Eligible participants were randomly assigned to receive a daily dose of micronutrients (vitamins A, B-complex, C, and E, and selenium) at multiples of recommended dietary allowance or a placebo at the time of initiating tuberculosis treatment. Overall, we did not find any effects of this specific micronutrient supplementation on immune function among tuberculosis patients, whether HIV negative or positive. However, among HIV-negative patients, there was a trend for improving the immune response following micronutrient supplementation, suggesting a modest beneficial impact of the supplements. In conclusion, we found no overall effects of micronutrient supplementation on immune responses among patients treated for pulmonary tuberculosis even though micronutrient supplements have been found to reduce the recurrence of TB in recovered patients. Supplements in our study did not include zinc or vitamin D, which have also been shown to play an important role in improving immune functions and the outcome of TB treatment. Our results thus far suggest that the role of nutritional intervention on the immune system remains an important area of research in order to discover a preventive therapy approach for this vulnerable population.
Technical Abstract: Limited studies exist regarding whether incorporating micronutrient supplements during tuberculosis (TB) treatment may improve cell-mediated immune response. We examine the effect of micronutrient supplementation on lymphocyte proliferation response to mycobacteria or T cell mitogens in a randomized trial conducted among 423 patients with pulmonary TB. Eligible participants were randomly assigned to receive a daily dose of micronutrients (vitamins A, B-complex, C, and E, and selenium) at multiples of recommended dietary allowance or placebo at the time of initiation of TB treatment. We found no significant effect of micronutrient supplements on lymphocyte proliferative responses to PHA or PPD among HIV-negative and HIV-positive TB patients. Compared with placebo, responses to ConA were significantly higher in the micronutrient arm among HIV-negative TB patients. The role of nutritional intervention in this vulnerable population remains an important area of future research.