title: Diagnostic Accuracy of Antigen 5-Based ELISAs for Human Cystic Echinococcosis.
abstract: BACKGROUND
  Clinical diagnosis and follow up of cystic echinococcosis (CE) are based on imaging complemented by serology. Several immunodiagnostic tests are commercially available, but the development of new tools is still needed to overcome the lack of standardization of the target antigen, generally consisting of a crude extract of Echinococcus granulosus hydatid cyst fluid. In a previous work, we described a chromatographic method for the preparation of a highly enriched Antigen 5 fraction from hydatid cyst fluid. The high reactivity of patient sera against this preparation prompted us to evaluate further this antigen for the serodiagnosis of CE on a larger cohort of samples.
  
  
  RESULTS
  A total of 327 sera from CE patients with heterogeneous conditions for cyst stage, cyst number, organ localization, drug therapy, and surgical intervention, together with 253 sera from healthy controls, were first analyzed by an ELISA based on the Ag5 preparation in two different experimental setups and, in parallel, by a commercial ELISA routinely used in clinical laboratories for CE serodiagnosis. The Ag5 ELISAs revealed different sensitivity (88.3% vs 95.3%) without significant differences in specificity (94.1% vs 92.5%), for the two setups, respectively. Moreover, possible relationships between the Ag5 ELISA absorbance results and clinical variables were investigated. Chi squared test, bivariate logistic regression and multiple regression analyses highlighted differences in the serology reactivity according to pharmacological treatment, cyst activity, and cyst number.
  
  
  CONCLUSIONS
  The two Ag5 ELISAs revealed different performances depending on the setup. The good diagnostic sensitivity and the high reliability of the Ag5 preparation method make this antigen a promising candidate for the serodiagnosis of CE. Further studies will be needed to evaluate the ability of our test to provide useful information on specific CE clinical traits.
authors.affiliation: Porto Conte Ricerche Srl, Tramariglio, Alghero (Sassari), Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Pagnozzi
authors.affiliation: Porto Conte Ricerche Srl, Tramariglio, Alghero (Sassari), Italy.
authors.forename: Maria Filippa
authors.initials: MF
authors.lastname: Addis
authors.affiliation: Porto Conte Ricerche Srl, Tramariglio, Alghero (Sassari), Italy.
authors.forename: Grazia
authors.initials: G
authors.lastname: Biosa
authors.affiliation: Porto Conte Ricerche Srl, Tramariglio, Alghero (Sassari), Italy.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Roggio
authors.affiliation: Porto Conte Ricerche Srl, Tramariglio, Alghero (Sassari), Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Tedde
authors.affiliation: Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy.|WHO Collaborating Centre for the Clinical Management of Cystic Echinococcosis, Pavia, Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Mariconti
authors.affiliation: Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy.|WHO Collaborating Centre for the Clinical Management of Cystic Echinococcosis, Pavia, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Tamarozzi
authors.affiliation: Department of Microbiology and Virology, IRCCS San Matteo Hospital Foundation and Department of Internal Medicine and Clinical Therapy, University of Pavia, Pavia, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Meroni
authors.affiliation: Centro Nazionale di Riferimento per l'Echinococcosi, IZS "G. Pegreffi", Sassari, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Masu
authors.affiliation: Centro Nazionale di Riferimento per l'Echinococcosi, IZS "G. Pegreffi", Sassari, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Masala
authors.affiliation: Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy.|WHO Collaborating Centre for the Clinical Management of Cystic Echinococcosis, Pavia, Italy.|Division of Infectious and Tropical Diseases, IRCCS San Matteo Hospital Foundation, Pavia, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Brunetti
authors.affiliation: Porto Conte Ricerche Srl, Tramariglio, Alghero (Sassari), Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Uzzau
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology* / Q000378:metabolism; D004443:Echinococcosis / Q000175:diagnosis*; D048209:Echinococcus granulosus / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods
chemical_list: D000947:Antigens, Helminth