IL-4 specific-response in whole blood associates with human Cystic Echinococcosis and cyst activity

Abstract

Objectives: Human Cystic Echinococcosis (CE) is estimated in 2-3 million global cases. CE diagnosis and clinical management are based on imaging and serology, which lacks sensitivity and does not provide cyst stage information. This study aimed to evaluate tools for improving diagnosis by analysing the Interleukin (IL)-4-response to Antigen B (AgB) of Echinococcus granulosus.

Methods: Whole blood (WB) and peripheral blood mononuclear cells were stimulated with AgB. IL-4 levels were measured by enzyme-linked immunosorbent assay.

Results: WB 1-day stimulation resulted the best experimental condition for evaluating AgB IL-4-response. IL-4 levels were significantly higher in CE patients than healthy donors (p ≤ 0.0001). A ROC analysis showed significant area under the curve (AUC) results (AUC, 0.85; p = 0.0001) identifying an IL-4 level cut-off point ≥0.39 pg/mL which predicted CE with 71.4% sensitivity and 93.3% specificity. Moreover, we found that IL-4 levels were significantly increased in patients with active cysts compared to those with inactive cysts (p ≤ 0.0001). ROC analysis showed significant AUC results (0.94; p = 0.0001) with a cut-off point of 4.6 pg/mL which predicted active cysts with 84.6% sensitivity and 92% specificity.

Conclusions: We found immunological correlates associated with CE and biological cyst activity.

Keywords: Active versus inactive cyst; Antigen B; Cysts monitoring; Diagnosis; Human Cystic Echinococcosis; IL-4; Serology; Ultrasonography; Whole blood.