title: Dual immune modulatory effect of vitamin A in human visceral leishmaniasis.
abstract: Vitamin A supplementation has shown to prevent mortality by diarrheal and respiratory diseases in several countries. Nevertheless, there are few studies investigating the effect of vitamin A in visceral leishmaniasis (VL), although there are reports of its deficiency in children with symptomatic VL in Brazil and Bangladesh. This study analyzed the effect of vitamin A on a subset of Treg cells and monocytes isolated from symptomatic VL and from healthy children residing in an endemic area for VL in Northeast Brazil. Serum retinol concentrations correlated inversely with IL-10 and TGF-β productions in CD4(+)CD25(high)Foxp3(+) T cells isolated from children with VL stimulated with leishmanial antigens. All-trans retinoic acid in vitro induced IL-10 in CD4(+)CD25(high)Foxp3(+) T cells; IL-10 and TGF-β production in CD4(+)CD25-Foxp3- T cells, and IL-10 in monocytes isolated from healthy children. However, the use of all-trans retinoic acid together with leishmanial antigens in vitro prevented increases in IL-10 production in Treg cells and monocytes isolated from VL children. Strikingly, those results show a potential dual role of vitamin A in the immune system: improvement of a regulatory profile in cells from healthy children after leishmanial stimulation and down modulation of IL-10 in Treg cells and monocytes during symptomatic VL. Therefore, the use of vitamin A concomitant to VL therapy might be useful in improving recovery from disease status caused by Leishmania infantum infection and warrants additional study.
authors.forename: Bruna L Lima
authors.initials: BL
authors.lastname: Maciel
authors.affiliation: Department of Nutrition, Health Sciences Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil; Department of Biochemistry, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil; Institute of Tropical Medicine of Rio Grande do Norte, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.
authors.forename: Bruna L
authors.initials: BL
authors.lastname: Lima Maciel
authors.affiliation: Department of Biochemistry, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.
authors.forename: Joanna Gardel
authors.initials: JG
authors.lastname: Valverde
authors.affiliation: Department of Biochemistry, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.
authors.forename: João Firmino
authors.initials: JF
authors.lastname: Rodrigues-Neto
authors.affiliation: Department of Biochemistry, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil; Institute of Tropical Medicine of Rio Grande do Norte, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.
authors.forename: Francisco
authors.initials: F
authors.lastname: Freire-Neto
authors.affiliation: Department of Biochemistry, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.
authors.forename: Tatjana S L
authors.initials: TS
authors.lastname: Keesen
authors.affiliation: Department of Biochemistry, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil; Institute of Tropical Medicine of Rio Grande do Norte, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil; National Institute of Science and Technology of Tropical Diseases (INCT-DT), Salvador, BA, Brazil.
authors.forename: Selma Maria Bezerra
authors.initials: SM
authors.lastname: Jeronimo
mesh_terms: D000293:Adolescent; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000378:metabolism; D004353:Drug Evaluation, Preclinical; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000494:pharmacology* / Q000627:therapeutic use; D007223:Infant; D007898:Leishmaniasis, Visceral / Q000188:drug therapy* / Q000276:immunology; D008297:Male; D014212:Tretinoin / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D016207:Cytokines; D007155:Immunologic Factors; D014212:Tretinoin