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Abnormal T-cell subset proportions in vitamin-A-deficient children
1Dana Center for Preventive Ophthalmology, Wilmer Institute, Baltimore, Maryland 21287-9019.
Insights
Vitamin A deficiency in children is linked to immune system T-cell abnormalities. Supplementation with vitamin A (retinol equivalent) can reverse these immune deficits, improving T-cell subsets and potentially reducing infection susceptibility.
Area of Science:
- Immunology
- Nutritional Science
- Pediatrics
Background:
- Vitamin A deficiency in children is associated with increased infection susceptibility and mortality.
- The biological mechanisms linking vitamin A deficiency to immune dysfunction remain largely unknown.
- T-cell subsets play a critical role in adaptive immunity.
Purpose of the Study:
- To investigate the association between vitamin A deficiency and T-cell subset abnormalities in children.
- To determine the effect of vitamin A supplementation on T-cell subsets in deficient children.
- To elucidate the immunological mechanisms underlying vitamin A's role in infection resistance.
Main Methods:
- A randomized, double-masked, placebo-controlled clinical trial was conducted in West Java, Indonesia.
- 55 children aged 3-6 years, with and without xerophthalmia, were studied.
- Measurements included CD4/CD8 ratios and proportions of specific T-cell subsets (CD4 naive, CD4 memory, CD8, CD45RA, CD8, CD45RO).
Main Results:
- Children with xerophthalmia (indicating vitamin A deficiency) exhibited lower CD4/CD8 ratios and reduced CD4 naive T cells.
- Vitamin A supplementation significantly increased CD4/CD8 ratios and CD4 naive T cells compared to placebo.
- Supplementation also led to a decrease in CD8, CD45RO T cells in the vitamin A group.
Conclusions:
- Vitamin A deficiency is associated with specific immune abnormalities in T-cell subsets.
- Vitamin A supplementation effectively reverses these immune T-cell subset abnormalities.
- These findings provide biological insights into how vitamin A impacts immune function and infection resistance in children.
Abstract:
Although vitamin A deficiency in children seems to increase susceptibility to infection and community trials have shown that vitamin A supplementation can reduce childhood mortality from infectious diseases, the underlying biological mechanisms are largely unknown. We conducted a randomised, double-masked, placebo-controlled clinical trial among children in West Java, Indonesia, to determine whether vitamin A deficiency is associated with abnormalities in T-cell subsets and whether vitamin A supplementation affects T-cell subsets. We studied 55 children aged 3-6 years--30 with xerophthalmia and 25 without. Acutely malnourished children (< 80% of reference weight-for-height) were excluded. CD4/CD8 ratios and the proportions of circulating CD4 naive, CD4 memory, CD8, CD45RA, and CD8, CD45RO T-cell subsets were measured. Children with xerophthalmia had lower CD4/CD8 ratios (p < 0.08), lower proportions of CD4 naive T cells (p < 0.03), and higher proportions of CD8, CD45RO T cells (p < 0.04) than those without xerophthalmia. 26 children were given vitamin A supplementation (60 mg retinol equivalent) and 29 received placebo. 5 weeks later the vitamin A group had higher CD4/CD8 ratios (p < 0.001), higher proportions of CD4 naive T cells (p < 0.01), and lower proportions of CD8, CD45RO T cells (p < 0.05) than the placebo group. Vitamin-A-deficient children have underlying immune abnormalities in T-cell subsets and these abnormalities are reversible with vitamin A supplementation.