Species-specificity preliminary evaluation of an IL-4 based test for the differential diagnosis of human echinococcosis

AIMS
The diagnosis of cystic echinococcosis (CE) is based on imaging, while serology is a complementary test of particular use when imaging is inconclusive. Serology has several limitations. Among them, false-positive results are often obtained in subjects with alveolar echinococcosis (AE), rendering difficult the differential diagnosis. We set-up an immune-assay based on IL-4-specific production after stimulating whole-blood with an antigen B (AgB) enriched fraction from E. granulosus, that associates with CE and CE cysts in active stage. We aimed to evaluate potential cross-reactivity of this test using samples from patients with AE.

METHODS AND RESULTS
Twelve patients with AE were recruited; IL-4 levels ranged from 0 pg/mL to 0.07 pg/mL. Based on the previously identified cut-off of 0.39 pg/mL using samples from patients with CE, none of samples from AE patients scored positive. In contrast, almost 80% of samples from AE patients scored positive in serology tests based on different E. granulosus-derived antigenic preparations.