Improved serodiagnosis of cystic echinococcosis using the new recombinant 2B2t antigen

Abstract

25 páginas, 1 figura, 5 tablas. This is an accepted manuscript to be released in PLoS Neglected Tropical DiseasesA standardized test for the serodiagnosis of human cystic echinococcosis (CE) is still needed, because of the low specificity and sensitivity of the currently available commercial tools and the lack of proper evaluation of the existing recombinant antigens. In a previous work, we defined the new ELISA-B2t diagnostic tool for the detection of specific IgGs in CE patients, which showed high sensitivity and specificity, and was useful in monitoring the clinical evolution of surgically treated CE patients. Nevertheless, this recombinant antigen gave rise to false-negative results in a percentage of CE patients. Therefore, in an attempt to improve its sensitivity, we constructed B2tderived recombinant antigens with two, four and eight tandem repeat of B2t units, and tested them by ELISA on serum samples of CE patients and patients with related parasites. The best diagnostic values were obtained with the two tandem repeat 2B2t antigen. The influence of several clinical variables on the performance of the tests was also evaluated. Finally, the diagnostic performance of the 2B2t-ELISA was compared with that of an indirect haemagglutination commercial test. The 2B2t recombinant antigen performed better than the HF and B2t antigens, and the IHA commercial kit. Therefore, this new 2B2t-ELISA is a promising candidate test for the serodiagnosis of CE in clinical settings.This work was supported by the Junta de Castilla y Leon, Spain (projects CSI269A11-2 and CSI08A08). AHG is a holder of a JAE predoctoral contract (CSIC, Spain). SS and SR acknowledge financial support of the National Institutes of Health-Fogarty International Center (training grant TW001140). HHG is now a Wellcome Trust Senior International Fellow in Public Health and Tropical Medicine. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe