Investigating new serological and tissue markers for the follow-up of patients operated for alveolar echinococcosis

The trajectory of anti-recEm18 antibody levels determines follow-up after curative resection of hepatic alveolar echinococcosis

INTRODUCTION

Recurrence after curative resection of hepatic alveolar echinococcosis remains a clinical challenge. 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 (n = 88) at the University Hospital Bern from 2002 to 2020 and at the University Hospital and Medical Center Ulm from 2011 to 2017 was performed. Analysis was directed to determine a potential association of pre- and postoperative values of anti-recEm18 with clinical outcomes.

RESULTS

Anti-recEm18 had a linear correlation to the maximum lesion diameter (R2 = 0.558). Three trajectories of anti-recEm18 were identified based on a threshold of 10 AU/ml: "Em18-low" (n = 31), "responders" (n = 53) and "residual disease" (n = 4). The decline of anti-recEm18 in "responders" reached a plateau after 10.9 months at which levels decreased by 90%. The only patient with recurrence in the entire population was also the only patient with a secondary increase of anti-recEm18.

CONCLUSION

In patients with preoperative elevated values, anti-recEm18 confirms curative surgery at 12 months follow-up and allows for long-term surveillance.

Programmed death-ligand1 is a determinant of recurrence in alveolar echinococcosis

OBJECTIVES

Alveolar echinococcosis (AE) recurrence is one of the major stakes in patients undergoing surgery, the main curative treatment. Preliminary data demonstrated an effect of programmed death-ligand1 (PD-L1) inhibitors on AE proliferation in animals. The current study aimed to analyze the prognostic value of PD-L1 expression in tissue samples of patients with AE undergoing surgery.

METHODS

A cross-sectional study of patients operated for AE between 2002 and 2017 was performed. Patients with recurrence were matched 1: 2 with patients without recurrence. The matching criteria were PNM staging (P = hepatic localization of the parasite, N = extra-hepatic involvement of neighboring organs, and M = absence or presence of metastasis), resection status, preoperative albendazole treatment, and lesion size. PD-L1 immunohistochemistry staining was performed in surgical liver specimens. The expression of PD-L1 was assessed in immune cells. Disease-free survival was calculated using the Kaplan-Meier method.

RESULTS

Among 68 consecutive patients, eight patients with recurrence were matched to 16 patients without recurrence. PD-L1 was overexpressed in patients with recurrence (recurrence: PD-L1 <1%: one, PD-L1 ≥1%: seven; no recurrence: PD-L1 <1%: nine, PD-L1 ≥1%: seven, P = 0.040). Moreover, patients with lower PD-L1 expression (<1%) showed better median disease-free survival (120 months, 95% confidence interval 104-135 vs 74, 95% confidence interval 44-104, P = 0.050).

CONCLUSION

These findings highlight the proof of concept of PD-L1 in AE, but further data on its prognostic importance and the role of immune checkpoint blockade as a promising therapeutical strategy are needed.

Basic Operative Tactics for Pulmonary Echinococcosis in the Era of Endostaplers and Energy Devices

Human echinococcosis is a zoonotic infection caused by the larvae of the tapeworm species Echinococcus. The liver is the most common location for a primary echinococcosis. However, the parasite may bypass or spread from the liver to the lungs, causing primary or secondary pulmonary echinococcosis, respectively. Pulmonary echinococcosis is a clinically challenging condition in which anthelminthic regiments are important, but surgery has the central role in removing the cysts and preventing recurrences. Surgical treatment may involve cystotomy, enucleation, capitonnage, or atypical resections, which occasionally are in combination with hepatic procedures. The utilization of modern devices is greatly underdescribed in surgery for thoracic infections, even though these facilitate much of the work. Therefore, this article aims to describe pulmonary echinococcosis and the role of modern surgical devices in the treatment process. Furthermore, we report surgical treatment of three different cases of pulmonary echinococcosis. Surgeries of uncomplicated and ruptured hepatic or pulmonary cysts are described. Simple small pulmonary echinococcal lesions can be excised by endostaplers both for diagnostic and curative reasons. Larger cysts can be removed by energy devices unless large bronchial air leaks occur. Complicated cysts require treatment by more extensive techniques. Inexperienced surgeons should not abstain but should carefully decide preoperatively how to proceed.

IEg67 kDa Bovine Hydatid Cyst Antigen: A Candidate for Developing Sero-Diagnostic Assays for Cystic Echinococcosis, a Disease of One Health Importance

Cystic echinococcosis (hydatidosis) is a world-wide zoonotic disease of mainly humans, livestock and dogs, caused by Echinococcus granulosus. The disease can negatively impact food production and animal welfare and causes socio-economic hardship. Here, we aimed to identify the local bovine hydatid cyst fluid (BHCF) antigen for developing a sero-diagnostic assay to be used for the pre-slaughter screening of food animals. In total, 264 bovines approved for slaughter in Pakistan were subjected to serum collection and post-mortem screening for hydatid cysts. These cysts were assessed microscopically to assess fertility and viability, and by PCR for molecular confirmation of species. A BHCF antigen was identified from positive sera via SDS-PAGE, confirmed by Western blot, and quantified via a bicinchoninic acid (BCA) assay. The quantified crude BHCF antigen (iEg67 kDa) was then used in ELISA screening to test all sera collected from known positive and negative animals based on hydatid cyst presence/absence. Of the 264 bovines examined, 38 (14.4%) showed hydatid cysts during post-mortem examination. All of these individuals, plus an additional 14 (total: 52; 19.6%) tested positive based on less time-consuming ELISA examination. Based on ELISA, occurrence in females (18.8%) was significantly higher than in males (9.2%) and was higher in cattle (19.5%) compared to buffalo (9.5%). The infection rate increased with age in both host species: cumulatively, 3.6% in animals aged 2-3 years, 14.6% in 4-5-year-olds and 25.6% in 6-7-year-olds. The occurrence of cysts in cattle was significantly higher in the lungs (14.1%) compared to their livers (5.5%), whereas the opposite was true in buffalo (6.6% livers, 2.9% lungs). For both host species, most cysts in the lungs were fertile (65%), while the majority in the liver were sterile (71.4%). We conclude that the identified iEg67 kDa antigen is a strong candidate for the development of a sero-diagnostic screening assay for the pre-slaughter diagnosis of hydatidosis.

Serum platelet-derived growth factor-BB levels as a potential biomarker in assessing the metabolic activity of lesions in alveolar echinococcosis patients

BACKGROUND

Alveolar echinococcosis (AE) is a chronic disease caused by the larval stage of Echinococcus multilocularis. Assessing the metabolic activity of AE lesions is critical to evaluate disease progression and survey treatment options. There is an urgent need to identify more rapid, convenient, and non-invasive clinical detection methods to substitute the current techniques. Herein, we evaluated the viability of platelet-derived growth factor-BB (PDGF-BB) as a biomarker for detecting the metabolic activity of AE patients and their correlations with clinicopathological features of AE patients.

METHODS

Sera were collected from 28 AE patients and a homogenous cohort of 28 healthy individuals. The concentration of serum PDGF-BB homodimers (sPDGF-BB) was assessed via an enzyme-linked immunosorbent assay (ELISA). Liver tissue samples were obtained from a consecutive series of 28 AE patients who underwent surgical resection. Thereafter, we determined the expression levels of local PDGF-BB and platelet-derived growth factor receptor-β (PDGFR-β) through immunohistochemistry (IHC). Correlations of PDGF-BB expression levels with clinicopathological features of AE patients were analyzed using SPSS.

RESULTS

The concentrations of sPDGF-BB were significantly lower in AE patients (p < 0.0001), particularly in High Metabolically Active AE patients (HMAE) patients (p < 0.05). The expression levels of PDGF-BB and its receptor were both significantly higher in close liver tissue (CLT) in AE patients (p < 0.0001). We also found that metabolically active AE and sPDGF-BB are significantly negatively correlated (r = -0.624, p = 0.0004). Beside, the local expression levels of PDGF-BB was positively correlated with metabolic activity, PNM stage, and lesion size. Notably, the sPDGF-BB levels were proposed as a potential biomarker for assessing metabolic activity of AE, with 81.0% sensitivity and 85.7% specificity (95% confidence interval, p = 0.003).

CONCLUSIONS

Serum levels of PDGF-BB could be a simple, non-invasive, and quick biomarker for assessing the metabolic activity of lesions in AE patients.

Echinococcus granulosus Protoscolex DM9 Protein Shows High Potential for Serodiagnosis of Alveolar Echinococcosis

Alveolar echinococcosis (AE) caused by infection with E. multilocularis metacestode, represents one of the most fatal helminthic diseases. AE is principally manifested with infiltrative, proliferating hepatic mass, resembling primary hepatocellular carcinoma. Sometimes metastatic lesions are found in nearby or remote tissue. AE diagnosis largely depends on imaging studies, but atypical findings of imaging features frequently require differential diagnosis from other hepatic lesions. Serological tests may provide further evidence, while obtaining reliable AE materials is not easy. In this study, alternative antigens, specific to AE were identified by analyzing E. granulosus protoscolex proteins. An immunoblot analysis of E. granulosus protoscolex showed that a group of low-molecular-weight proteins in the range from 14 kDa to 16 kDa exhibited a sensitive and specific immune response to AE patient sera. Partial purification and proteomic analysis indicated that this protein group contained myosin, tubulin polymerization promoting protein, fatty-acid binding protein, uncharacterized DM9, heat shock protein 90 cochaperone tebp P-23, and antigen S. When the serological applicability of recombinant forms of these proteins was assessed using enzyme-linked immunosorbent assay, DM9 protein (rEgDM9) showed 90.1% sensitivity (73/81 sera tested) and 94.5% specificity (172/181 sera tested), respectively. rEgDM9 showed weak cross-reactions with patient sera from the transitional and chronic stages of cystic echinococcosis (3 to 5 stages). rEgDM9 would serve as a useful alternative antigen for serodiagnosis of both early- and advanced-stage AE cases.