Human alveolar echinococcosis (AE), which is caused by the cestode Echinococcus (E.) multilocularis, is an epidemiologically relevant issue in modern medicine and still poses a diagnostic and therapeutic challenge. Since diagnosis mainly relies on imaging procedures and serological testing, we retrospectively and comparatively analyzed the performance of an Echinococcus IgG screening ELISA, whole serum IgE, and two specific confirmatory ELISA platforms using the defined E. multilocularis antigens Em2-Em18 (Em2+) and recombinant Em18 (recEm18). With special emphasis on the clinical usefulness of recEm18, we correlated the laboratory results with clinical characteristics and imaging findings in a large and well-characterized cohort of N = 124 AE patients, who were followed over several years after either surgical plus subsequent pharmacological treatment or pharmacotherapy alone. All patients had routinely received PET-CTI every two years. Our data reveal strong correlations for both Echinococcus IgG and recEm18 with tracer uptake in PET-CTI and parasitic lesion size and number, suggesting additional clinical usefulness of recEm18 for certain constellations only, while IgG and Em2+ still appear reasonable and sensitive screening methods for initial diagnosis of AE. With this study, we aim to contribute to further optimizing medical care of AE patients. For instance, it might be reasonable to consider the replacement of some PET-CTI follow-ups by imaging procedures with less radiation exposure or serological means alone. Further studies that clarify the correlation of serological markers with ultrasound criteria might be particularly useful, and further retrospective as well as prospective investigations are justified in this context.

Echinococcosis is a neglected zoonotic disease and a worldwide public health problem caused by infection with the larval stages of taeniid cestodes of the genus Echinococcus. In vitro studies have demonstrated a protoscolecidal effect of eosinophilic cationic protein (ECP), a granule protein of eosinophilic granulocytes, against E. granulosus. Therefore, the main objective of this study was to evaluate ECP as a biomarker in the treatment of alveolar echinococcosis (AE) and cystic echinococcosis (CE). Data were collected retrospectively from the Vienna Echinococcosis Cohort over 7 years until December 2020. Altogether, 32 patients (16 AE and 16 CE) were included. In the selected patients, serum ECP values were compared before and after the beginning of an operative and/or benzimidazole (BMZ) therapy. Mean ECP serum levels before intervention were significantly (p < 0.05) elevated at 34.0 ± 22.9 μg/L in AE patients and at 38.6 ± 19.9 μg/L in CE patients compared to the control group. After the intervention, mean ECP levels decreased significantly (p < 0.05) to 20.4 ± 14.6 μg/L in AE patients and to 22.4 ± 8.3 μg/L in CE patients. Furthermore, ECP showed a significant (p < 0.05) correlation of k = 0.56 with PET–CTI. Based on the significant decrease after operative and/or BMZ treatment and the correlation with clinical markers such as PET–CTI, it is recommended to investigate ECP more intensively as a marker of AE and CE in prospective studies with larger cohorts.

Background Best monitoring practices for patients after resection of hepatic alveolar echinococcosis remain unclear. Aims The current study tested if assessment of anti-recEm18 allows for postsurgical patient surveillance. Methods A retrospective study with patients undergoing liver resection for alveolar echinococcosis at the University Hospital Berne from December 2002 to December 2020 and at the University Hospital and Medical Center Ulm from January 2011 to December 2017 was performed. Analysis was directed to determine a potential association of pre- and postoperative values of anti-recEm18 with clinical outcomes. Results Among 147 patients who underwent liver resection for alveolar echinococcosis in curative intent, perioperative results of recEm18-serology were available in 88 patients. In patients without residual disease, the postoperative anti-recEm18 value after 12 months dropped to a mean of 2 AU/ml (standard deviation: 4 AU/ml). Three trajectories of anti-recEm18 were identified based on a threshold of 10 AU/ml: “Em18-low” (n = 31, 35%) with anti-recEm18 values below 10 AU/ml pre- and postoperatively, “responders” (n = 53, 60%) with preoperative values above 10 AU/ml and a postoperative decrease of more than 80% of the initial anti-recEm18 and “residual disease” (n = 4, 5%) with the postoperative presence of residual disease. The decline of anti-recEm18 in “responders” reached a plateau after 11.4 months at which levels decreased by 80%. The only recurrence in the entire population was identified by a secondary increase of anti-recEm18. Anti-recEm18 levels had a linear correlation to the maximum lesion diameter (R2 = 0.558). Conclusions Anti-recEm18 antibody levels correlate with the lesion size preoperatively and response to surgery postoperatively. Anti-recEm18 allows to be applied as serological surveillance marker during postoperative follow-up in patients with elevated preoperative anti-recEm18 levels.