title: [Reactivity of GST-SAPA antigen of Trypanosoma cruzi against sera from patients with Chagas disease and leishmaniasis].
abstract: Serologic diagnosis of Trypanosoma cruzi infection is important due to the limited sensitivity of direct parasitologic methods for diagnosis in the indeterminate and chronic phases of disease. SAPA antigen has been used in several studies and has been shown to be a good marker for use in the diagnosis of T. cruzi infection. Chagas disease and leishmaniasis are endemic in northern Salta with overlapping zones of transmission, which frequently leads to T. cruzi-Leishmania spp. mixed infections. Diagnosis is complicated by the fact that there is significant cross-reactivity when non-specific antigens are used. We evaluated the reactivity of GST-SAPA antigen in the ELISA test (ELISA-SAPA) against sera from persons infected with T. cruzi (n = 154), leishmaniasis (n = 66), mixed infections (29), and healthy controls (n = 28) using commercial ELISA and IHA kits as reference tests. For ELISA-SAPA the sensitivity, specificity and kappa index were calculated for detection of T. cruzi infection. Among sera from patients infected with leishmaniasis, 30.5% of co-infections were detected. ELISA-SAPA sensitivity was 97.1% (confidence interval 95%: 94.5-99.9), specificity was 100% (confidence interval 95%: 99.4-100), and kappa index was 96% (confidence interval 95%: 93-99%), for detection of T. cruzi infection. Sensitivity, specificity and kappa indices have shown a high efficiency of ELISA-SAPA.
authors.affiliation: Laboratorio de Química Biológica y Biología Molecular, Facultad de Ciencias Naturales, Universidad Nacional de Salta (LQByBM). jgil@conicet.gov.ar
authors.forename: José
authors.initials: J
authors.lastname: Gil
authors.forename: Rubén
authors.initials: R
authors.lastname: Cimino
authors.forename: Inés
authors.initials: I
authors.lastname: López Quiroga
authors.forename: Silvana
authors.initials: S
authors.lastname: Cajal
authors.forename: Norma
authors.initials: N
authors.lastname: Acosta
authors.forename: Marisa
authors.initials: M
authors.lastname: Juarez
authors.forename: Rosa
authors.initials: R
authors.lastname: Zacca
authors.forename: Viviana
authors.initials: V
authors.lastname: Orellana
authors.forename: Alejandro
authors.initials: A
authors.lastname: Krolewiecki
authors.forename: Patricio
authors.initials: P
authors.lastname: Diosque
authors.forename: Julio
authors.initials: J
authors.lastname: Nasser
mesh_terms: D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000276:immunology; D014355:Chagas Disease / Q000175:diagnosis* / Q000276:immunology; D003429:Cross Reactions / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D006023:Glycoproteins; D006801:Humans; D007898:Leishmaniasis, Visceral / Q000276:immunology*; D009439:Neuraminidase; D011994:Recombinant Proteins / Q000276:immunology; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods; D013045:Species Specificity; D014349:Trypanosoma cruzi / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D006023:Glycoproteins; D011994:Recombinant Proteins; C069715:trans-sialidase; D009439:Neuraminidase