Diagnostic and follow-up performance of serological tests for different forms/courses of alveolar echinococcosis

Bruno Gottstein,Anja Lachenmayer,Guido Beldi,Junhua Wang,Bernadette Merkle,Xuan Lan Vu,Ursula Kurath,Norbert Müller

doi:10.1016/j.fawpar.2019.e00055

Bruno Gottstein, Anja Lachenmayer + Show 6 more

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https://doi.org/10.1016/j.fawpar.2019.e00055

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Abstract

Diagnosis of alveolar echinococcosis (AE) is predominantly based on imaging procedures combined with immunodiagnostic testing. In the present study, we retrospectively analyzed the performance of four serological tests (EgHF-ELISA, Em2-ELISA, recEm18-ELISA and Em-Immunoblotting) for initial diagnosis and subsequent monitoring of AE patients. Overall, 101 AE patients were included, grouped according to treatment options and immune status as follows: (A) curative surgical treatment (n = 45 patients), (B) non-radical or palliative surgical treatment (n = 11), (C) benzimidazoles only (n = 20), (D) immunocompromised with radical surgical treatment (n = 11), (E) immunocompromised with benzimidazoles only (n = 4), and finally a group of 10 AE patients (F) that were considered to present so-called “abortive” lesions. Initial (i.e. pretreatment) ELISA-based diagnosis for patients in groups A to E revealed overall diagnostic sensitivities of 95% for EgHF, 86% for Em2, and 80% for recEm18, respectively. Comparatively, the diagnostic sensitivity of Em-Immunoblotting was higher with an overall value of 98%. In group F, only Em-Immunoblotting had an excellent diagnostic sensitivity (100%), whereas the ELISAs had poor sensitivities of 30% (EgHF- and Em2-ELISA) or even 0% (recEm18-ELISA).Serological monitoring of AE patients showed a clear association between a curative development of disease (induced either by surgery or benzimidazole medication) and a negativization in the ELISAs. This effect was most pronounced for the recEm18-ELISA, where 56% negativized following diagnosis/treatment, as compared to 36% for the EgHF-ELISA, and 37% for the Em2-ELISA, respectively. After radical surgery, the mean time until negativization in the recEm18-ELISA was 2.4 years (SD 1.6). This was significantly shorter than the mean 3.9 years (SD 2.5) in those AE patients with non-radical, palliative surgery or ABZ treatment who were able to negativize during the study period (p = 0.048).Conclusively, Em-Immunoblotting appears as the most sensitive test to diagnose active as well as inactive (“abortive”) AE-cases. The inclusion of the ELISAs completes the initial diagnostic picture and offers valuable additional information. Conversely, recEm18-ELISA appears as the currently best serological tool to monitor a regressive and putatively curative course of AE in treated patients.

Highlights

Alveolar echinococcosis (AE) is a severe parasitic disease caused by the larval form, the metacestode, of Echinococcus multilocularis
Substantial efforts have been undertaken to optimize the performance of serological tests for both, initial diagnosis of AE, as well as for long-time monitoring of peri- and/or post-therapeutical courses in AE patients
The latter is of special interest in view of gaining predictive information about a successful, i.e. curative, outcome of treatment, which might contribute to an abrogation of the daily medication necessary to control AE in non-radically operated AE patients

Summary

Introduction

Alveolar echinococcosis (AE) is a severe parasitic disease caused by the larval form, the metacestode, of Echinococcus multilocularis. Symptomatic AE is conventionally diagnosed by imaging procedures demonstrating the presence of various forms of the E. multilocularis metacestode-induced lesions in the liver tissue (Brunetti et al, 2010; Grüner et al, 2017; Wen et al, 2019). Confirmation of this initial diagnosis is routinely performed by serology.

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