Effect of zinc supplementation on cell-mediated immunity and lymphocyte subsets in preschool children

Abstract

Objective: In a zinc supplementation trial (with a significant impact on diarrheal morbidity), to evaluate effect of zinc supplementation on cellular immune status before and after 120 days of supplementation.

Design: A double blind, randomized controlled trial with immune assessment at baseline and after 120 days on supplement.

Setting: Community based study in an urban slum population.

Subjects: Randomly selected children (zinc 38, control 48), had a Multitest CMI skin test at both times. In 66 children (zinc 22, control 34), proportions of CD3, CD4, CD8, CD16, CD20 cells and the CD/CD8 ratio were also estimated using a whole blood lysis method and flowcytometry.

Intervention: Zinc gluconate to provide elemental zinc 10 mg daily and 20 mg during diarrhea.

Main outcome results: Regarding CMI, the percentage of anergic or hypoergic children (using induration score) decreased from 67% to 47% in the zinc group, while in the control group it remained unchanged (73% vs 71%) (p = 0.05). The percentage of children deteriorating between first and second tests was significantly lower in the zinc group (13% vs 33%, p = 0.03). Regarding lymphocyte subsets, the zinc group had a significantly higher rise in the geometric means of CD3 (25%, p = 0.02), CD4 (64% p = 0.001), and CD4/CD8 ratio (73% p = 0.004) with no difference in CD8 and CD20. The rise in CD4 was significantly higher in the zinc as compared to the control group; the ratio of geometric means was 1.45 (95% CI, 1.03-2.01).

Conclusion: Zinc supplementation improves cellular immune status, which may have been one of the mechanisms for observed impact of zinc supplementation on diarrheal morbidity.