title: Field validation of a Leishmania (Leishmania) mexicana exo-antigens ELISA for diagnosing tegumentary leishmaniasis in regions of Leishmania (Viannia) predominance.
abstract: BACKGROUND
  Several tests are performed to obtain better accuracy when diagnosing American tegumentary leishmaniasis (ATL). It is believed that antigens released via secretion, excretion and metabolism are more specific than are antigens released by the lysis of Leishmania parasites. Such antigens are known as exo-antigens (exo-Ag) and are formed from products released by cultured parasites in a way that is similar to that in which they cause infections in hosts.
  
  
  OBJECTIVE
  We attempted to validate a Leishmania mexicana ELISA exo-Ag for ATL diagnosis in Midwestern Brazil.
  
  
  METHODS
  A total of 281 patients were included in the study. We analysed pre-treatment blood from 98 ATL patients; out of those, 85.7% and 14.3% had cutaneous and mucosal forms, respectively.
  
  
  RESULTS
  The exo-Ag accuracy was 83.99% (95% CI=79.24-87.81) with a sensitivity value of 90.82% (95% CI=83.46-95.09) and an overall specificity value of 80.33% (95% CI=73.97-85.44). The positive predictive value and negative predictive value were 71.20% (95% CI=62.72-78.41) and 94.23% (95% CI=89.40-96.94), respectively. Among healthy controls, exo-Ag had a specificity of 91.25% (95% CI=83.02-95.70); additionally, the test had specificity rates of 66.67% (95% CI=46.71-82.03) in Chagas disease patients, 60.61% (95% CI=43.68-75.32) in patients with rheumatic diseases, 76.92% (95% CI=49.74-91.82) in pemphigus foliaceus patients, 87.50% (95% CI=52.91-97.76) in leprosy patients, 87.50% (95% CI=63.98-96.50) in VRDL-positive patients, and 77.78 (95% CI=45.26-93.68) in deep mycosis patients.
  
  
  CONCLUSIONS
  Based on the indicators of validity, we conclude that the results obtained in this study enable the recommendation of the exo-Ag ELISA for ATL diagnosis once it presented a reasonable accuracy compared to classical methods. Cost evaluations are necessary to completely define the role of this technique in large scale.
authors.affiliation: Pós-Graduação em Ciências Médicas, Universidade de Brasília (UnB), Brasília, DF, Brazil.
authors.forename: Killarney Ataide
authors.initials: KA
authors.lastname: Soares
authors.affiliation: Pós-Graduação em Ciências Médicas, Universidade de Brasília (UnB), Brasília, DF, Brazil.
authors.forename: Ada Amália Ayala
authors.initials: AA
authors.lastname: Urdapilleta
authors.affiliation: Escola Superior de Ciências da Saúde - ESCS, Faculdade de Medicina, Brasília, DF, Brazil.
authors.forename: Gilcilene Maria dos
authors.initials: GM
authors.lastname: Santos
authors.affiliation: Pós-Graduação em Ciências Médicas, Universidade de Brasília (UnB), Brasília, DF, Brazil.
authors.forename: Andréa Lisboa
authors.initials: AL
authors.lastname: Carneiro
authors.affiliation: Pós-Graduação em Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (FMRP-USP), Ribeirão Preto, SP, Brazil; Dermatology, Brasília, Universidade de Brasília (UnB), Brasília, DF, Brazil. Electronic address: ciromgomes@gmail.com.
authors.forename: Ciro Martins
authors.initials: CM
authors.lastname: Gomes
authors.affiliation: Laboratório de Dermatologia - Hospital das Clínicas de Ribeirão Preto, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (FMRP-USP), Ribeirão Preto, SP, Brazil.
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Roselino
authors.affiliation: Pós-Graduação em Ciências Médicas, Universidade de Brasília (UnB), Brasília, DF, Brazil; Dermatology, Brasília, Universidade de Brasília (UnB), Brasília, DF, Brazil; Faculdade de Medicina, Universidade de Brasília (UnB), Brasília, DF, Brazil.
authors.forename: Raimunda Nonata Ribeiro
authors.initials: RN
authors.lastname: Sampaio
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000953:Antigens, Protozoan / Q000097:blood*; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007892:Leishmania braziliensis / Q000276:immunology*; D007894:Leishmania mexicana / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000175:diagnosis* / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D000953:Antigens, Protozoan
keywords: Diagnostics; Disease control; Infectious disease; Leishmaniasis