title: Advances in flow cytometric serology for canine visceral leishmaniasis: diagnostic applications when distinct clinical forms, vaccination and other canine pathogens become a challenge.
abstract: We have previously reported the applicability of flow cytometry anti-fixed Leishmania infantum chagasi promastigotes IgG (FC-AFPA-IgG) as a novel serological device for laboratorial diagnosis of CVL. Herein, we validate throughout a blind study applied into a broader range of coded sera samples that FC-AFPA-IgG at serum dilution 1:8192 have an outstanding performance to discriminate the serological reactivity of canine visceral leishmaniasis (CVL, n=64) and Leishmune vaccines (VAC, n=62) and non-infected controls (NI, n=25). Moreover, we have evaluated the performance of indirect immunofluorescence antibody test (IFAT) and the crude-antigen enzyme-linked immunosorbent assay (ELISA) in parallel with FC-AFPA-IgG, to discriminate the seroreactivity of NI, CVL and VAC. Our data demonstrated that both ELISA and FC-AFPA-IgG showed similar performance to detect the seronegativity in 100% of NI, whereas FC-AFPA-IgG displayed better performance to exclude seropositivity in 100% of VAC. The high kappa agreement indexes observed suggested similar performance between these two serological testes when distinct clinical forms of CVL become a challenge. Furthermore, the FC-AFPA-IgG applied at sera dilution 1:8192 showed a remarkable performance to discriminate CVL from other co-endemic canine infections with high co-negativity in dogs infected with Trypanosoma cruzi and Leishmania braziliensis (86% and 84%, respectively). In conclusion, the data presented here re-emphasize the applicability of FC-AFPA-IgG as an innovative methodology able to discriminate post-infection imunomediated seroreactivity from that triggered by prophylactic immunization with minor cross-reactivity with other relevant canine pathogens, which may contribute as a supplementary assay for the CVL immunodiagnosis.
authors.affiliation: Laboratório de Biomarcadores de Diagnóstico e Monitoração, CPqRR-FIOCRUZ/MG, Avenida Augusto de Lima 1715, Barro Preto, Belo Horizonte, 30190-002 Minas Gerais, CEP, Brazil.
authors.forename: Renata Aline
authors.initials: RA
authors.lastname: Andrade
authors.forename: Márcio Sobreira
authors.initials: MS
authors.lastname: Silva Araújo
authors.forename: Alexandre Barbosa
authors.initials: AB
authors.lastname: Reis
authors.forename: Célia Maria Ferreira
authors.initials: CM
authors.lastname: Gontijo
authors.forename: Leonardo Rocha
authors.initials: LR
authors.lastname: Vianna
authors.forename: Wilson
authors.initials: W
authors.lastname: Mayrink
authors.forename: Olindo Assis
authors.initials: OA
authors.lastname: Martins-Filho
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D003429:Cross Reactions; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000175:diagnosis* / Q000276:immunology; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D005434:Flow Cytometry / Q000662:veterinary*; D007074:Immunoglobulin G / Q000276:immunology; D018314:Leishmania infantum / Q000276:immunology*; D054332:Leishmaniasis Vaccines / Q000276:immunology*; D007898:Leishmaniasis, Visceral / Q000175:diagnosis / Q000276:immunology / Q000662:veterinary*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000662:veterinary
chemical_list: D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; D054332:Leishmaniasis Vaccines