title: Higher sensitivity of immunohistochemistry for bona fide diagnosis of dog Leishmania (Viannia) braziliensis-driven American tegumentary leishmaniasis: description of an optimized immunohistochemistry method.
abstract: BACKGROUND
  The in situ detection of parasite antigens in tissue sections by immunohistochemistry (IHC) is a diagnostic alternative for human American tegumentary leishmaniasis (ATL), but has not been used for the diagnosis of cutaneous lesions in dogs with ATL. This study describes the results of IHC for the detection of amastigote forms and other Leishmania sp. antigen-positive cells and compares the results of IHC, histopathology and cytopathology for the diagnosis of canine ATL. In addition, possible cross-reactivity with sporotrichosis is analyzed.
  
  
  METHODS
  Forty paraffin-embedded biopsies and 40 smears of cutaneous lesions from dogs with ATL, confirmed by isolation and characterization of Leishmania (Viannia) braziliensis, and 40 paraffin-embedded biopsies of cutaneous lesions from dogs with sporotrichosis, confirmed by isolation of Sporothrix schenckii in culture (control group), were studied.
  
  
  RESULTS
  Immunohistochemistry was more sensitive in detecting amastigote forms than cytopathology and histopathology, with a positivity rate of 70% (n=28) versus 37.5% and 22.5% for histopathology and cytopathology, respectively. Cytoplasmic staining of mononuclear and endothelial cells was detected by IHC, which was highly specific since no cytoplasmic staining of these cells or staining of fungal structures was observed in sporotrichosis fragments.
  
  
  CONCLUSIONS
  In view of the higher sensitivity of IHC in detecting Leishmania sp. antigen and patterns of positivity for Leishmania sp. antigen compared to histopathology or cytopathology and the absence of cross-reactions with sporotrichosis, we recommend this technique for the diagnosis of canine tegumentary leishmaniasis.
authors.affiliation: Programa de Epidemiologia e Vigilância em Saúde (PEPIVS), FIOCRUZ BRASILIA, Avenida L3 Norte, s-n, campus Universitario Darcy Ribeiro, Gleba A, CEP: 70910-000-Brasilia-DF belebarbieri@yahoo.com.br isabele.santos@ioc.fiocruz.br.
authors.forename: Isabele Barbieri
authors.initials: IB
authors.lastname: dos Santos
authors.affiliation: Serviço de Anatomia Patológica Doutor Jefferson Andrade dos Santos - Faculdade de Veterinária - Universidade Federal Fluminense, Niterói, RJ, Brazil.
authors.forename: Rogerio
authors.initials: R
authors.lastname: Tortelly
authors.affiliation: Serviço de Anatomia Patológica, Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Leonardo Pereira
authors.initials: LP
authors.lastname: Quintella
authors.affiliation: Serviço de Parasitologia, Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Maria
authors.initials: M
authors.lastname: de Fátima Madeira
authors.affiliation: Serviço de Dermatozoonoses, Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Luisa Helena
authors.initials: LH
authors.lastname: Monteiro de Miranda
authors.affiliation: Serviço de Dermatozoonoses, Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Fabiano
authors.initials: F
authors.lastname: Borges Figueiredo
authors.affiliation: Serviço de Epidemiologia, Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Raquel de Vasconcellos
authors.initials: Rde V
authors.lastname: Carvalhaes de Oliveira
authors.affiliation: Serviço de Dermatozoonoses, Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Tânia Maria
authors.initials: TM
authors.lastname: Pacheco Schubach
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology; D004283:Dog Diseases / Q000175:diagnosis* / Q000276:immunology; D004285:Dogs; D007150:Immunohistochemistry / Q000379:methods / Q000592:standards / Q000662:veterinary*; D007892:Leishmania braziliensis / Q000276:immunology / Q000302:isolation & purification*; D016773:Leishmaniasis, Cutaneous / Q000175:diagnosis / Q000276:immunology / Q000662:veterinary*; D012680:Sensitivity and Specificity
chemical_list: D000953:Antigens, Protozoan
keywords: American tegumentary leishmaniasis; Brazil; Dogs; Immunohistochemistry