title: Immunologic Markers of Protection in Leishmania (Viannia) braziliensis Infection: A 5-Year Cohort Study.
abstract: The control of Leishmania braziliensis by individuals with subclinical infection (SC) are unknown.
  
  
  
  A cohort of 308 household contacts (HCs) of patients with cutaneous leishmaniasis (CL) was established in 2010 in an endemic area and followed up for 5 years. Whole-blood cultures stimulated with soluble Leishmania antigen and a Leishmania skin test (LST) were performed in years 0, 2, and 4. The identification of the lymphocyte subsets secreting interferon (IFN) γ and the ability of monocytes to control Leishmania were determined.
  
  
  
  During follow-up, 118 subjects (38.3%) had evidence of L. braziliensis infection. Of the HCs, CL was documented in 45 (14.6%), 101 (32.8%) had SC infection, and 162 (52.6%) did not have evidence of exposure to L. braziliensis The ratio of infection to disease was 3.2:1. IFN-γ production, mainly by natural killer cells, was associated with protection, and a positive LST result did not prevent development of disease. Moreover, monocytes from subjects with SC infection were less permissive to parasite penetration and had a greater ability to control L. braziliensis than cells from patients with CL.
  
  
  
  Protection against CL was associated with IFN-γ production, negative LST results, impaired ability of Leishmania to penetrate monocytes, and increased ability to control Leishmania growth.
authors.affiliation: Serviço de Imunologia, Hospital Universitário Professor Edgard Santos, Federal University of Bahia Postgraduate Program in Health Sciences, Federal University of Bahia School of Medicine.
authors.forename: Aline C
authors.initials: AC
authors.lastname: Muniz
authors.affiliation: Serviço de Imunologia, Hospital Universitário Professor Edgard Santos, Federal University of Bahia Postgraduate Program in Health Sciences, Federal University of Bahia School of Medicine Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais.
authors.forename: Olívia
authors.initials: O
authors.lastname: Bacellar
authors.affiliation: Serviço de Imunologia, Hospital Universitário Professor Edgard Santos, Federal University of Bahia.
authors.forename: Ednaldo Lima
authors.initials: EL
authors.lastname: Lago
authors.affiliation: Postgraduate Program in Health Sciences, Federal University of Bahia School of Medicine Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz (FIOCRUZ), Salvador.
authors.forename: Augusto M
authors.initials: AM
authors.lastname: Carvalho
authors.affiliation: Serviço de Imunologia, Hospital Universitário Professor Edgard Santos, Federal University of Bahia Postgraduate Program in Health Sciences, Federal University of Bahia School of Medicine.
authors.forename: Pedro Paulo
authors.initials: PP
authors.lastname: Carneiro
authors.affiliation: Serviço de Imunologia, Hospital Universitário Professor Edgard Santos, Federal University of Bahia.
authors.forename: Luiz Henrique
authors.initials: LH
authors.lastname: Guimarães
authors.affiliation: Postgraduate Program in Health Sciences, Federal University of Bahia School of Medicine Department of Medicine and Diagnostic Support, Federal University of Bahia School of Medicine, Brazil.
authors.forename: Paulo N
authors.initials: PN
authors.lastname: Rocha
authors.affiliation: Serviço de Imunologia, Hospital Universitário Professor Edgard Santos, Federal University of Bahia Postgraduate Program in Health Sciences, Federal University of Bahia School of Medicine Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz (FIOCRUZ), Salvador.
authors.forename: Lucas P
authors.initials: LP
authors.lastname: Carvalho
authors.affiliation: Weill Cornell Medical College, New York, New York.
authors.forename: Marshall
authors.initials: M
authors.lastname: Glesby
authors.affiliation: Serviço de Imunologia, Hospital Universitário Professor Edgard Santos, Federal University of Bahia Postgraduate Program in Health Sciences, Federal University of Bahia School of Medicine Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz (FIOCRUZ), Salvador.
authors.forename: Edgar M
authors.initials: EM
authors.lastname: Carvalho
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D001769:Blood / Q000276:immunology; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D007892:Leishmania braziliensis / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology* / Q000517:prevention & control*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D012882:Skin Tests; D055815:Young Adult
chemical_list: D015415:Biomarkers; D007371:Interferon-gamma
keywords: IFN-γ; Leishmania braziliensis; Leishmania skin test; cutaneous leishmaniasis; household contacts; subclinical leishmaniasis