Effect of zinc supplementation on t-cell subset proportions and cell-mediated immunity

In a double blind zinc supplementation trial with a significant impact on diarrhea! morbidity, we evaluated cellular immune status before and after 120 days of supplementation. Randomly selected 86 children (zinc 38, control 48), were applied Multitest CMI skin test at both times, in 66 children (zinc 22, control 34), proportions of CD3, CD4, CD8, CD16, CD20 and CD4/CD8 ratio were also estimated using a whole blood lysis method and flowcytometry. For both estimations the two groups were comparable for baseline features. For CMI estimations the percentage of anergic or hypoergic children in the zinc group decreased from 67% to 47% while in control group it remained unchanged (73% vs. 71%) (p=0.05). Five children (13%) in zinc group deteriorated one level down, in comparison to 16 children (33%) in the control group (p=0.03). For T-cell subset estimations, in the zinc group there was a significant rise in the geometric means of CD3 (32% p = 0.008), CD4 (64% p=0.001), CD4/CD8 ratio (73% p=004). There was no change in CD8 and CD20. CD4 rise was significantly higher in zinc as compared to the control group, ratio of geometric mean 1.45 (95%CI 1.03-2.01). Our findings indicate that zinc supplementation had a beneficial effect on cellular immunity, which may have been one of the mechanisms for the observed impact of zinc supplementation on diarrheal morbidity.