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High-Dose Neonatal Vitamin A Supplementation Transiently Decreases Thymic Function in Early Infancy.


ABSTRACT:

Background

Vitamin A deficiency (VAD) impairs T-cell-mediated immunity. In regions where VAD is prevalent, vitamin A supplementation (VAS) reduces child mortality, perhaps by improving immune function.

Objective

Our objective was to determine if neonatal VAS would improve thymic function in Bangladeshi infants, and to determine if such effects differed by sex or nutritional status (i.e., birth weight above/below the median).

Methods

Three hundred and six infants were randomly assigned to 50,000 IU vitamin A (VA) or placebo (PL) within 48 h of birth. Primary outcomes were measured at multiple ages and included 1) thymic index (TI) at 1, 6, 10, and 15 wk; 2) T-cell receptor excision circles (TREC), an index of thymic output of naïve T cells; and 3) total/naïve T cells in peripheral blood at 6 wk, 15 wk, and 2 y. A mixed linear model for repeated measures was used to assess group differences at each age and identify interactions with sex and birth weight.

Results

VAS did not significantly (P = 0.21) affect TI overall (i.e., at all ages) but decreased TI by 7.8% (P = 0.029) at 6 wk: adjusted TI means for the PL and VA groups at 1, 6, 10, and 15 wk were 4.09 compared with 3.80 cm2, 7.78 compared with 7.18 cm2, 8.11 compared with 7.84 cm2, and 7.91 compared with 7.97 cm2, respectively. VAS did not significantly (P = 0.25) affect TREC overall but decreased TREC by 19% (P = 0.029) at 15 wk: adjusted TREC means for the PL and VA groups at 6 wk, 15 wk, and 2 y were 13.6 compared with 16.1 copies/pg DNA, 19.4 compared with 15.7 copies/pg DNA, and 11.8 compared with 10.0 copies/pg DNA, respectively. VAS did not significantly affect overall total (P = 0.10) or naïve (P = 0.092) T cells: adjusted naïve T-cell means for the PL and VA groups at 6 wk, 15 wk, and 2 y were 3259 compared with 3109 cells/µL, 3771 compared with 3487 cells/µL, and 1976 compared with 1898 cells/µL, respectively.

Conclusion

In contrast to our hypothesis, VAS decreased thymic function early in infancy but health effects are presumably negligible owing to the transience and small magnitude of this effect. This trial was registered at clinicaltrials.gov as NCT01583972 and NCT02027610.

SUBMITTER: Ahmad SM 

PROVIDER: S-EPMC6946900 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

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High-Dose Neonatal Vitamin A Supplementation Transiently Decreases Thymic Function in Early Infancy.

Ahmad Shaikh M SM   Raqib Rubhana R   Huda M Nazmul MN   Alam Md J MJ   Monirujjaman Md M   Akhter Taslima T   Wagatsuma Yukiko Y   Qadri Firdausi F   Zerofsky Melissa S MS   Stephensen Charles B CB  

The Journal of nutrition 20200101 1


<h4>Background</h4>Vitamin A deficiency (VAD) impairs T-cell-mediated immunity. In regions where VAD is prevalent, vitamin A supplementation (VAS) reduces child mortality, perhaps by improving immune function.<h4>Objective</h4>Our objective was to determine if neonatal VAS would improve thymic function in Bangladeshi infants, and to determine if such effects differed by sex or nutritional status (i.e., birth weight above/below the median).<h4>Methods</h4>Three hundred and six infants were random  ...[more]

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