Vitamin A status inversely correlates with IL-10 and TGF-beta production by Treg cells in human visceral leishmaniasis.
Human, visceral leishmaniasis, vitamin A, regulatory T cells.
Vitamin A supplementation has long been used in developing countries to prevent mortality by diarrheal and respiratory diseases, but there are few studies on its role in Leishmania infection, although we and others have previously found vitamin A deficiency in VL patients. Regulatory T (Treg) cells are induced by vitamin A metabolites and have recently been suggested as important cells implicated in CD4+ suppression in human VL. This work analyzed the effect of vitamin A in the response against Leishmania infection in a subset of Treg cells and monocytes isolated from children with VL and healthy children from an endemic area to L. infantum infection. Our results show that serum retinol concentrations are inversely correlated to IL-10 and TGF-β production in CD4+CD25highFoxp3+ T cells after SLA stimulus. Furthermore, we show that the use of all-trans retinoic acid in vitro produces no beneficial effects on CD4+CD25highFoxp3+ T cells, CD4+CD25-Foxp3- T cells and monocytes of children in risk of Leishmania infection and children with VL. The results indicate that the maintenance of an optimal vitamin A status is important to L. infantum infection, but do not support the use of vitamin A supplementation in VL.