Immunodiagnosis of echinococcosis in cancer patients

Abstract

Objective: To study cross-reactions to Echinococcus granulosus hydatid fluid antigen (EgHF) in ELISA tests on serum from patients with malignancies. Methods: The study was based on the use of different ELISAs and a subsequent Western blot test for the confirmation of positive ELISA results. Results: We found that cross-reactions with the EgHF ELISA were unusually high (6.3%) in patients with malignancies as compared with sera from healthy subjects (0.5%, p < 0.05). Seropositive patients suffered significantly less frequently from advanced, consuming malignancy as compared with patients with a negative EgHF ELISA (24% versus 55%, p < 0.05). The Western blot test remained negative with respect to the diagnostically relevant 8-kDa band in all patients with a positive EgHF ELISA reaction. Conclusions: The screening EgHF ELISA for E. granulosus is associated with relatively frequent false-positive reactions in tumor patients, whereas the Western blot test is a specific immunodiagnostic tool enabling discrimination between malignancy and parasitic hydatid disease.