title: The effect of vitamin A supplementation on the intestinal immune response in Mexican children is modified by pathogen infections and diarrhea.
abstract: Vitamin A supplementation has consistently reduced infant mortality and the severity of pathogen-induced diarrhea. The mechanism by which vitamin A modulates the mucosal immune response to produce these effects remains poorly defined. To address this issue, stools collected during the summer months from 127 Mexican children 5-15 mo old enrolled in a larger, randomized, double-blind, placebo-controlled, vitamin A supplementation trial were screened for interleukin (IL)-4, IL-6, interferon-gamma (IFN-gamma), and gastrointestinal pathogens. Fecal cytokine values were categorized into 3 levels (undetectable, <median, > or =median). Multinomial regression models were used to determine the probability that vitamin A-supplemented children had higher categorical values of a cytokine than children in the placebo group. Differences in categorical values were also analyzed after stratification by gastrointestinal pathogen infections and diarrheal symptoms. Overall, fecal cytokine categorical levels did not differ between children randomized to the 2 arms. Vitamin A-supplemented children infected with enteropathogenic E. coli (EPEC) had reduced IL-4 and IFN-gamma levels [odds ratio (OR) = 0.3, 95% CI 0.13-0.67 and OR = 0.34, 95% CI 0.14-0.83, respectively] compared with children in the placebo group. Vitamin A-supplemented children had increased IL-4 levels when infected with A. lumbricoides (OR = 12.06, 95% CI 0.95-153.85). In contrast, IL-4 levels increased (OR = 2.14, 95% CI 0.94-4.87) and IFN-gamma levels decreased (OR = 0.51, 95% CI 0.26-0.99) among vitamin A-supplemented children with diarrhea compared with children in the placebo group. These findings suggest that the regulation of the mucosal immune response by vitamin A may depend on the type of enteric pathogen infecting the child and the presence of clinical symptoms.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, Boston, MA, USA. klong@hsph.harvard.edu
authors.forename: Kurt Z
authors.initials: KZ
authors.lastname: Long
authors.forename: Teresa
authors.initials: T
authors.lastname: Estrada-Garcia
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Rosado
authors.forename: Jose
authors.initials: J
authors.lastname: Ignacio Santos
authors.forename: Meredith
authors.initials: M
authors.lastname: Haas
authors.forename: Mathew
authors.initials: M
authors.lastname: Firestone
authors.forename: Jui
authors.initials: J
authors.lastname: Bhagwat
authors.forename: Cheryl
authors.initials: C
authors.lastname: Young
authors.forename: Herbert L
authors.initials: HL
authors.lastname: DuPont
authors.forename: Ellen
authors.initials: E
authors.lastname: Hertzmark
authors.forename: Nanda N
authors.initials: NN
authors.lastname: Nanthakumar
mesh_terms: D000818:Animals; D001196:Ascariasis / Q000276:immunology; D001200:Ascaris / Q000302:isolation & purification; D001827:Body Height; D001835:Body Weight; D003140:Communicable Disease Control; D003967:Diarrhea / Q000276:immunology* / Q000469:parasitology; D019587:Dietary Supplements; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D018928:Immunity, Mucosal / Q000187:drug effects*; D007223:Infant; D008297:Male; D008800:Mexico; D012959:Socioeconomic Factors; D018417:Th1 Cells / Q000382:microbiology; D018418:Th2 Cells / Q000276:immunology; D014801:Vitamin A / Q000494:pharmacology*
chemical_list: D014801:Vitamin A