Subclass-specific serological reactivity and IgG4-specific antigen recognition in human echinococcosis

Alveolar Echinococcosis in a Patient with Presumed Autoimmune Hepatitis and Primary Sclerosing Cholangitis: An Unexpected Finding after Liver Transplantation

Primary sclerosing cholangitis is an important reason for liver transplantation. Hepatic alveolar echinococcosis (AE) is caused by Echinococcus multilocularis and presents characteristic calcified conglomerates detected by ultrasound or computed tomography scan of the liver. Symptoms of AE only occur after a long period of infection when cholestasis or cholangitis becomes apparent. Here, we report on a patient with presumed autoimmune hepatitis and primary sclerosing cholangitis. After liver transplantation, alveolar echinococcosis was diagnosed in the liver explant.

One-tube nested MGB Probe Real-time PCR assay for detection of Echinococcus multilocularis infection in plasma cell free DNA

INTRODUCTION

The main objective of this study was to develop a One-tube nested MGB probe real-time PCR Assay for detecting Echinococcus multilocularis infection in human plasma cell free DNA (cfDNA).

METHODS

cfDNA was extracted from 10 E.m.-infected patients using a NucleoSnap DNA Plasma Kit and characterized by genomic sequencing. We designed nested PCR primers and MGB probe for Echinococcus multilocularis detection. The specificity, sensitivity and reproducibility of this assay were analyzed, and its validity was confirmed in 13 early stage clinical samples.

RESULTS

Several Echinococcus multilocularis-specific sequences were detected in the cfDNA of E.m.-infected patients, and CBLO020001206.1 was selected as the candidate sequence. We designed the primers and probe for the one tube nested real-time PCR. No cross-reactions with E.g. were observed. The detection limit was as low as 1 copy for Echinococcus multilocularis. The coefficients of variation were lower than 5% in intra- and inter-assays. 11 out of 13 patients were positive with nested MGB Probe PCR Assay and 3 patients were positive without outer primer in early stage Alveolar Echinococcosis pateints.

CONCLUSION

The one-tube nested MGB probe real-time PCR assay is a simple, rapid, and cost-effective method for detection of Echinococcus multilocularis infection in patients' Plasma DNA.

Echinococcus multilocularis specific antibody, systemic cytokine, and chemokine levels, as well as antigen-specific cellular responses in patients with progressive, stable, and cured alveolar echinococcosis: A 10-year follow-up

Background

The infestation with Echinococcus multilocularis larvae may persist in humans for up to decades without evident clinical symptoms. Longitudinal investigations are needed to understand the dynamic immunological processes in alveolar echinococcosis (AE) patients associated with an active and progressive, a stable or a regressive course of disease.

Methodology/Principal findings

This study evaluated the E. multilocularis specific antibody responses, systemic cytokine, and chemokine serum levels over a 10-year follow-up period, as well as cellular responsiveness in AE patients. Our results demonstrate a rapid decrease in antibodies against E. multilocularis specific antigen Em2+. Especially in cured patients, these antibodies remained negative, making them a significant predictor for cured AE. E. multilocularis specific IgG4, and indirect hemagglutination IHA decreased later in time, after around 5 years. While total IgE did not show significant dynamics over the course of disease, E. multilocularis specific IgE decreased after one to two years, and increasing levels were a significant predictor of progressive disease. There was no significant change in systemic IL-8, IL-9, CCL18 or CCL20 serum levels over time. Univariate analysis across groups indicated lower IL-8 levels in cured patients; however, this result could not be confirmed by multivariate analysis. Levels of CCL17 decreased during treatment, especially in cured patients, and thus might serve as a predictive or risk factor for progressive disease. Levels of IL-10 and CCL13 decreased during disease, especially after five and ten years of intervention. The E. multilocularis antigen (EmAg) inducible cellular productions of MCP1(CCL13), TARC(CCL17) and PARC(CCL18) were lowest in patients with cured AE and infection-free controls, while the EmAg inducible cellular production of IFN-γ increased after cure. Significant positive cytokine and chemokine correlations were observed in AE patients for IL-9, IL-10, CCL13(MCP-4), CCL17(TARC) and CCL20(LARC)(for all p<0.001). E. multilocularis specific IgG4 response correlated positively with TARC (p<0.001). Both markers enhanced over time in progressive disease and decreased after cure. The levels of IL-8, IL-10, MCP4 and LARC enhanced with AE regression.

Conclusions/Significance

Repeated biomarker surveys are advisable to evaluate progression or regression of disease during longitudinal follow-up and such analyses can support imaging techniques and improve staging of AE patients.

Alveolar echinococcosis (AE) is a severe disease caused by Echinococcus multilocularis, the fox tapeworm. Humans exposed to E. multilocularis may develop severe AE with progressive tissue and organ infiltrating growth of the larval stage. The E. multilocularis larvae appear to have developed effective immune evasion mechanisms which facilitate an asymptomatic incubation and an extended host and parasite coexistence for decades. Over a 10-year follow-up, this investigation aimed to gain a better understanding of the immunological process associated with an active and progressive, a stable or a regressive course of AE. In summary, the rapid decrease of antibodies against the E. multilocularis specific antigen Em2+, especially in cured patients, makes them a significant predictor for cured AE. The positive relation of E. multilocularis specific IgG4 responses and chemokine levels of TARC can indicate AE progression when both enhance over time. Enhanced levels of cytokines IL-8, IL-10, and chemokines MCP4 and LARC may predict AE regression. Repeated biomarker surveys are advisable to evaluate progression or regression of AE during longitudinal follow up, and such analyses can support imaging techniques and improve staging of AE patients.

PET/CT helps to determine treatment duration in patients with resected as well as inoperable alveolar echinococcosis

PURPOSE

The aim of the study was to determine the role of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) at the end of benzimidazole therapy in alveolar echinococcosis.

METHODS

A total of 22 patients undergoing PET/CT at the end of benzimidazole therapy were retrospectively registered. Maximum standardized uptake values (SUV_max) were measured in remaining echinococcus manifestations and compared to normal liver tissue. Long-term clinical follow-up was performed, and recorded data included laboratory parameters, clinical information and imaging.

RESULTS

All patients had no detectable levels of Em-18 antibodies and all echinococcus manifestations were negative on PET/CT, i.e. without focally increased FDG uptake or uptake higher than normal/non-infected liver tissue. All manifestations displayed significantly less FDG-uptake than normal liver tissue, i.e. SUVmax 1.8 (interquartile range (IQR) 1.5-3.5) vs. 3.0 (IQR 2.6-5.7), (p < 0.001). Patients were clinically followed for a median of 9.5 years (IQR 6.5-32.0 years) after their initial diagnosis and for 4.5 years (IQR 3.0-14.0 years) after discontinuation of benzimidazole therapy. No patient showed signs of recurrent infection at the last clinical visit. The 10-year and 20-year freedom from all-cause mortality was 95.0% (95% confidence interval 69.5% - 99.3%), for both. Two events occurred in 292 patient years of follow-up; i.e. two patients (9%) died, one because of pancreatic cancer, the other one because of unknown reasons with no detectable antibody levels.

CONCLUSIONS

Negative FDG-PET/CT results combined with no detectable levels of Em-18 antibodies may allow for the safe discontinuation of benzimidazole therapy in patients with alveolar echinococcosis.

Gallbladder Hydatid Cyst: A Review on Clinical Features, Investigations and Current Management

Background

Gallbladder hydatid cyst (GBHC) is highly uncommon with an incidence of 0.3–0.4% of all atypically located hydatid cysts. Our personal experience of one case of primary GBHC (PGBHC) managed laparoscopically motivated this systematic review. This study aimed to analyze the demographic characteristics, types [whether primary GBHC (PGBHC) or secondary GBHC (SGBHC)], clinical presentation, laboratory investigations, imaging studies, operative procedure, hospital stay, follow-up and recurrence.

Methods

A systematic review was performed using preferred reporting items for systematic reviews and meta-analyses guidelines.

Results

Twenty studies, including 22 cases plus one more case managed by us, were included in the review. For PGBHC, the mean age was 48.61 years while for SGBHC it was 47.9 years. PGBHC was more common in females (69.23%) while SGBHC was more common in males (55.55%). Overall, GBHC was more common in females (56.52%). The most common presentation overall was abdominal pain (100%) followed by nausea/vomiting (43.47%). The other common symptoms were nausea/vomiting (61.53%) and Murphy’s sign (38.46%) in PGBHC, but jaundice (50%) and fever (30%) in SGBHC. In PGBHC, 50% patients had normal liver function while this was deranged in 66.66% patients with SGBHC. Serology was positive in 50% of PGBHC and 100% in SGBHC. Ultrasonography was positive in 50%, while CT-scan showed 70%. CT-scan was better at detection of SGBHC (100%). The most common operation was open cholecystectomy (78.26%) either isolated or combined. Isolated open cholecystectomy was commonly done in PGBHC (69.23%). Overall, only 56.52% of patients received albendazole, but no recurrence was reported. The average hospital stay was 7.25 days and follow-up ranged from 1 month to 10 years.

Conclusion

GBHC mostly affects females with abdominal pain being the most common symptom. Ultrasonography is expedient though CT-scan is more sensitive. Albendazole monotherapy has questionable value. Open cholecystectomy is the most common operation. However, laparoscopy is safe in experienced hands.

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Current status of diagnosis and treatment of hepatic echinococcosis

Echinococcus granulosus (E. granulosus) and Echinococcus multilocularis (E. multilocularis) infections are the most common parasitic diseases that affect the liver. The disease course is typically slow and the patients tend to remain asymptomatic for many years. Often the diagnosis is incidental. Right upper quadrant abdominal pain, hepatitis, cholangitis, and anaphylaxis due to dissemination of the cyst are the main presenting symptoms. Ultrasonography is important in diagnosis. The World Health Organization classification, based on ultrasonographic findings, is used for staging of the disease and treatment selection. In addition to the imaging methods, immunological investigations are used to support the diagnosis. The available treatment options for E. granulosus infection include open surgery, percutaneous interventions, and pharmacotherapy. Aggressive surgery is the first-choice treatment for E. multilocularis infection, while pharmacotherapy is used as an adjunct to surgery. Due to a paucity of clinical studies, empirical evidence on the treatment of E. granulosus and E. multilocularis infections is largely lacking; there are no prominent and widely accepted clinical algorithms yet. In this article, we review the diagnosis and treatment of E. granulosus and E. multilocularis infections in the light of recent evidence.

Distinctive cytokine, chemokine, and antibody responses in Echinococcus multilocularis-infected patients with cured, stable, or progressive disease

Metacestode larvae of the tapeworm Echinococcus multilocularis can cause alveolar echinococcosis (AE), a severe parasitic disease in man, which, if it remains untreated, may cause organ failure and death. Spontaneous and parasite antigen-induced cellular responses were studied in patients with cured, stable, and progressive AE to differentiate the response profiles between the distinct states of infection. Antibody reactivity was evaluated in AE patients with cured, stable, and progressive disease. The spontaneous cellular release of pro-inflammatory IL-31 and IL-33 was clearly depressed in all AE patients, while regulatory IL-27, anti-inflammatory SDF-1/CXCL12, and eosinophil granulocyte attracting Eotaxin-1, Eotaxin-2, and Eotaxin-3 (CCL11, CCL24, CCL26) were enhanced with disease progression. Such distinctive response profiles could be applied for monitoring of AE disease progression or regression. E. multilocularis metacestode (Em) antigens (entire metacestode EmAg as well as EmVesicles) stimulated in vitro IL-31, IL-33, Eotaxin-1, Eotaxin-3, and CXCL12 cytokine and chemokine responses, which were similarly present in all AE patient groups, while regulatory IL-27 was suppressed and pro-inflammatory Eotaxin-2 was enhanced. E. multilocularis metacestode-specific IgG1, IgG3, and IgE responses progressively diminished with regression from active to stable and cured AE. IgG2 and IgG4 reactivity remained similarly high in stable and progressive cases, and lessened only with cured AE. Antibody reactivity against E. multilocularis vesicle antigen distinctively separated between cured, stable, or progressive AE, with the exception of IgG4. In sum, the combined and longitudinal study of several cytokines and chemokines, together with the evaluation of E. multilocularis vesicle-specific antibody responses, should provide a better understanding of the immune response during progression and regression of AE, and may help to improve the staging of AE patients.

Hepatic echinococcosis: Clinical and therapeutic aspects

Echinococcosis or hydatid disease (HD) is a zoonosis caused by the larval stages of taeniid cestodes belonging to the genus Echinococcus. Hepatic echinococcosis is a life-threatening disease, mainly differentiated into alveolar and cystic forms, associated with Echinoccus multilocularis (E. multilocularis) and Echinococcus granulosus (E. granulosus) infection, respectively. Cystic echinococcosis (CE) has a worldwide distribution, while hepatic alveolar echinococcosis (AE) is endemic in the Northern hemisphere, including North America and several Asian and European countries, like France, Germany and Austria. E. granulosus young cysts are spherical, unilocular vesicles, consisting of an internal germinal layer and an outer acellular layer. Cyst expansion is associated with a host immune reaction and the subsequent development of a fibrous layer, called the pericyst; old cysts typically present internal septations and daughter cysts. E. multilocularis has a tumor-like, infiltrative behavior, which is responsible for tissue destruction and finally for liver failure. The liver is the main site of HD involvement, for both alveolar and cystic hydatidosis. HD is usually asymptomatic for a long period of time, because cyst growth is commonly slow; the most frequent symptoms are fatigue and abdominal pain. Patients may also present jaundice, hepatomegaly or anaphylaxis, due to cyst leakage or rupture. HD diagnosis is usually accomplished with the combined use of ultrasonography and immunodiagnosis; furthermore, the improvement of surgical techniques, the introduction of minimally invasive treatments [such as puncture, aspiration, injection, re-aspiration (PAIR)] and more effective drugs (such as benzoimidazoles) have deeply changed life expectancy and quality of life of patients with HD. The aim of this article is to provide an up-to-date review of biological, diagnostic, clinical and therapeutic aspects of hepatic echinococcosis.

Cross-Reaction between the Crude Hydatid Cyst Fluid Antigens of Human and Animals Origin in Response to Human IgG Class and Subclasses

The current work aimed to evaluate the cross-reactivity of human immune sera against crude hydatid fluid antigens of sheep, human, mouse, cattle, as well as B fraction of cystic fluid antigen. 30 balb/c mice were infected with sheep hydatid cyct fluid antigen containing protoscolex after the viability of these protoscolices was assessed. ANOVA was used to test the difference of themean of optical density (OD) values among case and control groups. The highest human IgG class antibody was against antigen B (0.93) and the lowest against cattle HCF antigen (0.32). The differences between responses to these antigens were statistically significant (P < 0.001). The sensitivity and specificity of ELISA test used for evaluating the responses of human total IgG to different hydatid cyst fluid (HCF) antigens among the case and control groups were 100 and 95.8%, respectively. Cross-reaction of human IgG class and subclasses responses was found almost for all the antigens with the best reaction against human and cattle (HCF) antigens and antigen B using a ratio of mean OD value to each antigen divided by the cut-off point value for the same antigen. Human sera showed a considerable cross-reactivity against all antigens by using ELISA.

Understanding the laminated layer of larval Echinococcus II: immunology

The laminated layer (LL) is the massive carbohydrate-rich structure that protects Echinococcus larvae, which cause cystic echinococcosis (hydatid disease) and alveolar echinococcosis. Increased understanding of the biochemistry of the LL is allowing a more informed analysis of its immunology. The LL not only protects the parasite against host attack but also shapes the overall immune response against it. Because of its dense glycosylation, it probably contains few T-cell epitopes, being important instead in T-cell independent antibody responses. Crucially, it is decoded in non-inflammatory fashion by innate immunity, surely contributing to the strong immune-regulation observed in Echinococcus infections. Defining the active LL molecular motifs and corresponding host innate receptors is a feasible and promising goal in the field of helminth-derived immune-regulatory molecules.

Immunoglobulin G subclass responses to recombinant Em18 in the follow-up of patients with alveolar echinococcosis in different clinical stages

In this study, we compared the sequential responses of immunoglobulin G (IgG) subclasses to the diagnostic antigen Em18 in sera from patients with alveolar echinococcosis. A total of 225 sera from 36 patients at different clinical stages according to the WHO-PNM staging system were tested. The antibody responses were measured for cohorts with resected and unresected parasitic lesions by enzyme-linked immunosorbent assays (ELISA). Total IgG and, to a lesser extent, IgG4 antibody levels against Em18 correlated with all PNM stages before treatment, whereas levels of IgG2 were low and IgG3 was undetectable. Antibody kinetics, however, depended on the treatment rather than on the PNM stage. For some patients, after curative surgery, IgG1 antibodies dropped below the cutoff earlier than other antibodies, followed by total IgG and IgG4 within 18 months. For some patients with recurrences after surgery, IgG1 and IgG4 reappeared, whereas patients with unresectable lesions but stable disease showed steady declines in the levels of all antibodies, and IgG1 became undetectable in some patients. Additional testing of IgE responses to Em18 showed constantly low levels at all stages and in all cohorts.

Echinococcus multilocularis and its intermediate host: a model of parasite-host interplay

Host-parasite interactions in the E. multilocularis-intermediate host model depend on a subtle balance between cellular immunity, which is responsible for host's resistance towards the metacestode, the larval stage of the parasite, and tolerance induction and maintenance. The pathological features of alveolar echinococcosis. the disease caused by E. multilocularis, are related both to parasitic growth and to host's immune response, leading to fibrosis and necrosis, The disease spectrum is clearly dependent on the genetic background of the host as well as on acquired disturbances of Th1-related immunity. The laminated layer of the metacestode, and especially its carbohydrate components, plays a major role in tolerance induction. Th2-type and anti-inflammatory cytokines, IL-10 and TGF-β, as well as nitric oxide, are involved in the maintenance of tolerance and partial inhibition of cytotoxic mechanisms. Results of studies in the experimental mouse model and in patients suggest that immune modulation with cytokines, such as interferon-α, or with specific antigens could be used in the future to treat patients with alveolar echinococcosis and/or to prevent this very severe parasitic disease.

Evaluation of a commercial Echinococcus Western Blot assay for serological follow-up of patients with alveolar echinococcosis

A total of 20 patients with alveolar echinococcosis in different clinical stages according to the WHO-PNM staging system (P, parasitic mass in the liver; N, involvement of neighboring organs; M, metastasis) were followed up serologically with the commercial Echinococcus Western Blot IgG assay and a crude antigen extract enzyme-linked immunosorbent assay (ELISA). The cohort included patients after curative resection and patients who had unresectable lesions with stable disease or progressive infection. There were visible correlations of the crude antigen ELISA index and the presence and intensity of diagnostic bands in the Western blot. In most patients after curative resection, bands at 7, 16, and 18 kDa markedly decreased or vanished after 1 to 4 years. In a patient with a nonviable lesion (it died out), bands at 16 and 18 kDa vanished after 4 years. Among individuals with unresectable lesions but stable disease under antiparasitic chemotherapy, a decrease of all diagnostic bands was visible after 2 to 3 years in half of the patients, whereas the other half had unchanged blot results after 4 to 6 years. Patients with progressive disease showed increasing intensities of bands at 16, 18, and 7 kDa. The change of banding patterns was not influenced by the PNM stage in patients after curative surgery or with unresectable lesions. Our data indicate a correlation of the 7-, 16-, and 18-kDa-Western blot bands with disease activity independent of the PNM stage. This study demonstrated the usefulness of the Echinococcus Western Blot IgG assay as an additional serological test for the follow-up of patients with alveolar echinococcosis.

[Recent advances in the immunodiagnosis of human cystic echinococcosis]

Human cystic echinococcosis is a severe zoonotic infection caused by the larval stage of the taeniid tapeworm Echinococcus granulosus. The infection may be fatal if proper treatment is not provided; hence, early diagnosis is very important. Currently, ELISA and immunoblotting are the most reliable tests for serodiagnostic purposes, although their accuracy is largely dependent on the quality of the antigenic source used. Hydatid cyst fluid has been the antigenic extract of choice for primary immunodiagnosis of the disease, which is mainly based on the detection of antigens B and 5. Several problems are associated with this extract, however, including a lack of sensitivity and specificity, and difficulties with standardization of its use. This paper reviews recent advances in the identification and characterization of novel antigens that may be useful for the immunodiagnosing of human cystic echinococcosis, with emphasis on progress in recombinant technologies and synthetic peptides. Novel approaches are discussed, such as the design of antigenic extracts from other developmental stages of the parasite, as well as the usefulness of serum cytokine detection in the clinical follow-up of affected patients after surgical or pharmacological treatment.

The immunodiagnosis of Echinococcus multilocularis infection

Alveolar echinococcosis (AE) is a severe zoonotic disease caused by the metacestode stage of Echinococcus multilocularis. The infection can have fatal consequences in humans if treatment is not provided, so early diagnosis is fundamental for initiating treatment and reducing morbidity and mortality. In addition, detection of the parasite in the definitive host plays a central role in epidemiological studies and surveillance programmes for control of AE. This review presents an overview of the present situation regarding the immunodiagnosis of E. multilocularis infection. Special attention is given to the description of the native, partially purified and recombinant antigens available currently for immunodiagnostic purposes. Recent advances in the primary serodiagnosis and follow-up of AE patients are highlighted, including the detection of specific cytokine profiles. Progress in the immunodiagnosis of intestinal E. multilocularis infection in definitive hosts, particularly the detection of excretory-secretory and integument products of the worm in faeces (copro-antigens) by ELISA, is also discussed.

Echinococcosis and allergy

The larval stages of Echinococcus granulosus and E. multilocularis are involved in parasitic diseases in humans: cystic echinococcosis (CE) ("hydatid disease") and alveolar echinococcosis (AE), respectively. Both diseases and parasites have tight links with allergy because of the immunological characteristics that contribute to maintain the larvae in their human host as well as their potential in inducing clinical anaphylactic reactions in some patients. Clinical observations in patients and data obtained from mass screenings in various countries have identified both forms of echinococcosis as "polar diseases," i.e., diseases where immunological background of the patients was related to the clinical presentation and course. In particular, abortive cases (i.e., spontaneous cures) have been found in many subjects in endemic areas. On the other hand, immune suppression was associated with severe disease. AE especially might be considered as an opportunistic infection. Experimental and clinical studies have shown that Th1-related immune response was associated with protection and Th2-related response was associated with parasite growth. Genetic characteristics of the host are related to both occurrence and severity of AE and are associated with the extent of IL-10 secretion, which is a major feature of chronic progressing echinococcosis. Anaphylactic reactions, including urticaria, edema, respiratory symptoms, and anaphylactic shock due to spontaneous or provoked rupture of the parasitic cyst, are well known in CE. Anaphylactic reactions in AE are far less frequent, and have been observed in rare cases at time of metastatic dissemination of the parasitic lesions. Echinococcus-specific IgE is present in most of the patients and associated with severity. Specific histamine release by circulating basophils stimulated with E. granulosus antigens is present in all patients with CE and AE. Echinococcus allergens include (1) AgB 12-kDa subunit, a protease inhibitor and a potent Th2 inducer; (2) Ag5, a serine protease; (3) EA 21, a specific cyclophilin, with a homology with other types of cyclophilins; (4) Eg EF-1 beta/delta an elongation factor, with a homology with Strongyloides stercoralis EF that shares the same IgE epitope. A clinical cross-reaction with Thiomucase, a mucopolysaccharidase used in arthritis treatment, has recently been published. However, despite the potential risk of allergic reactions, the dogma "never puncture a hydatid cyst" is no longer valid. International experience of therapeutic technique of "puncture, aspiration, injection, re-aspiration" of hydatid cysts developed at the beginning of the 1980s has proved to be successful in a variety of selected indications that have been reviewed by WHO recommendations. A better understanding of the immunological background of echinococcosis in humans has led to new therapeutic developments, such as immunomodulation using interferon alpha. Th2-driven immunological response and IL-10-related tolerance state are common characteristics of atopic allergy and echinococcosis. The example of echinococcosis stresses the ambiguous links that exist between parasitic and allergic diseases, and show the usefulness of comparing these diseases to better understand how immune deviation may lead to pathological events and to find new therapeutic and.or preventive agents.

A new ImmunoCAP assay for detection of Echinococcus multilocularis-specific IgE

In alveolar echinococcosis (AE), caused by Echinococcus multilocularis (E.m.), increased levels of total and parasite-specific IgE are frequently found. These may not only have diagnostic but are also supposed to have prognostic value in the follow-up of AE patients. However, there is no commercial test available for quantification of E. m.-specific IgE (sIgE). The only commercial test available is based on E. granulosus (g.) hydatid antigen, which is not optimal for detection of E. m.-specific IgE. Therefore, a new ImmunoCAP with covalently bound crude antigen of E. m. was developed in cooperation with Pharmacia Research Forum for the analysis of E. m. sIgE. The E. m. ImmunoCAP was evaluated in 53 AE patients with different clinical disease progression and 20 healthy controls. Our data showed a higher sensitivity for sIgE determination with E. m. ImmunoCAP compared to the E. g. ImmunoCAP (73.6% vs 61.5%) and a positive correlation between total IgE and sIgE. Furthermore, there was a significant correlation between sIgE in both tests. In conclusion, the new E. m.-specific ImmunoCAP test proved to be a valuable tool for determination of sIgE. It may provide the basis for the development of further E. multilocularis-specific IgE immunotests which are essential for evaluation of sIgE during clinical course of AE.

Serodiagnosis of ascariasis with specific IgG4 antibody and its use in an epidemiological study

In an earlier study Ascaris-specific IgG4 antibody was found to be elevated in cases of ascariasis. However, the usefulness of the elevated levels of this antibody in Ascaris infection as a diagnostic marker has not been well established. In India, in early 1999, blood samples of 83 cases of Ascaris infection, 35 cases of other nematode infection and 53 control subjects (without any helminth infection) were tested for anti-Ascaris IgG4 by ELISA. Further anti-Ascaris IgG4 levels in the blood of Ascaris-infected patients were determined, after eradication of the worms with drugs, at regular intervals to ascertain the duration of elevation of titre of the serological marker following initial infection. This information would indicate the sensitivity of the test as a diagnostic marker for recent infection. Blood samples of 422 rural people were also tested for anti-Ascaris IgG4 titre to ascertain the prevalence of ascariasis in the community. High levels of anti-Ascaris IgG4 antibody (OD 1.246 +/- 0.212) were found in all the 83 Ascaris-infected subjects compared to controls (OD 0.158 +/- 0.047). Anti-Ascaris IgG4 antibody levels of other nematode-infected subjects were comparable to the controls. Anthelmintic treatment of 8 Ascaris-infected subjects caused sequential fall of IgG4 level in their blood, and its titre reached control level within 6 months of deworming. Of 422 individuals from the rural community 229 (54.3%) had significantly high levels of specific IgG4 antibody against Ascaris excretory-secretory antigen, suggesting that they were infested with Ascaris. Thus, this study demonstrated that anti-Ascaris IgG4 antibody is a very sensitive and specific marker for the diagnosis of Ascaris infection. Utilizing this test, a significant number of a rural population could be diagnosed with Ascaris infection in West Bengal, India.

Immunodiagnosis of Echinococcus infections: confirmatory testing and species differentiation by a new commercial Western Blot

The Echinococcus Western Blot IgG (LDBIO Diagnostics, Lyon, France), using a whole larval antigen from Echinococcus multilocularis, was evaluated for serodiagnosis and differentiation between two human parasitic infections of worldwide importance: cystic echinococcosis, due to Echinococcus granulosus, and alveolar echinococcosis, due to E. multilocularis. Fifty and 61 serum samples from patients with cystic and alveolar echinococcosis, respectively, were used for assessing diagnostic sensitivity. The sensitivity of the assay was compared with those of screening tests used for these applications. Sera used for assessing cross-reactivities were from 154 patients with other diseases, either parasitic or not. The assay allowed the detection of serum immunoglobulin G antibodies in 97% of Echinococcus-infected patients. It had a higher sensitivity than screening assays for the detection for each echinococcosis. The assay allowed us to correctly distinguish between E. granulosus- and E. multilocularis-infected patients in 76% of cases. It did not allow us to distinguish active from inactive forms of both echinococcoses. The occurrence of cross-reactivities with neurocysticercosis indicates the necessity for retesting sera with species-specific antigens, for rare patients with neurologic disorders. This study shows the usefulness of the commercially available Echinococcus Western Blot IgG for the serological confirmation of human echinococcosis.

Pericystic metabolic activity in alveolar echinococcosis: assessment and follow-up by positron emission tomography

Information on parasite viability in alveolar echinococcosis (AE) cannot be obtained by conventional imaging techniques. We evaluated the glucose metabolism of AE lesions by use of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) in 12 inoperable patients. Eight patients showed either perilesional or focal enhancement ("hot spots"), whereas 4 patients had nonenhancing (metabolically inactive) lesions. With PET, necrotic parasitic lesions and areas of enhanced metabolic activity could be clearly discriminated. Most notably, 3 of 8 patients with metabolically active lesions who were reexamined after chemotherapy treatment clearly showed improvement: the initial surrounding hot spots had disappeared in 2 of them, and had significantly decreased in 1. PET may prove valuable in assessing the efficacy of chemotherapy by showing the disappearance of metabolic activity and may also be useful for timely detection of relapses and metastases. Although costly and not readily available, FDG-PET is a promising tool toward improved management of AE and may thus help lower costs of long-term chemotherapy.

Cytokine and chemokine secretion by human peripheral blood cells in response to viable Echinococcus multilocularis metacestode vesicles

In human alveolar echinococcosis, asexually proliferating metacestodes of Echinococcus multilocularis progressively infiltrate host tissues and cause serious pathology to the affected organs. This study employed an in vitro culture of E. multilocularis and examined the production of cytokines and chemokines by peripheral blood cells from echinococcosis patients in response to viable proliferating E. multilocularis metacestode vesicles (Em-vesicles). A significant interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) production was elicited in echinococcosis patients when their cells were cocultured with viable Em-vesicles and autologous immune sera. Furthermore, in echinococcosis patients, substantial amounts of cytokines were detected; and the levels of IL-12 and IL-13 found in patients correlated with the actual state of clinical disease. These observations suggest that viable E. multilocularis vesicles will induce significant cellular production of cytokines and chemokines in patients, and that such immune mediators may activate and enhance antibody-dependent cellular effector mechanism against proliferating metacestodes of E. multilocularis.

Interleukin (IL)-4, IL-10 and IL-12 profile in serum of patients with alveolar echinococcosis

Alveolar echinococcosis (AE), caused by Echinococcus multilocularis (E.m.), provokes a characteristic immune response. Based mainly on in vitro studies, Th2 dominated immunity is associated with increased susceptibility to disease, while Th1 cell activation is assumed to induce protective immunity. We investigated serum levels of interleukin (IL)4, IL-10, and IL-12 in 40 AE patients and 20 controls to assess Th1/Th2 cell activation in vivo. Significantly higher levels of IL-10 were found in AE patients (P = 0.003) than in controls, with a tendency to higher concentrations in progressive cases. In contrast, IL-4 was only measurable in a minority of patients and controls. IL-12 levels (measured with an ELISA that detects both the p35/p40 heterodimer and free p40) were comparable between AE patients and controls and showed a similar distribution pattern to IL-10 with regard to disease progression. By using an IL-12-ELISA specific for the heterodimer, only minute amounts of IL-12 were detectable in merely a minority of samples. In conclusion, our data are suggestive of Th2 dominated immune response in AE in vivo.

T lymphocyte cytokine profile at a single cell level in alveolar Echinococcosis

The metacestode Echinococcus multilocularis causes a life-threatening disease in humans, named alveolar echinococcosis (AE). A comparative analysis of the early activation marker CD69 on peripheral blood mononuclear cells (PBMC) of patients with AE and healthy controls after in vitro culture with crude E. multilocularis antigen revealed that specific expression of CD69 was induced in CD4(+)T lymphocytes as well as in CD8(+)T lymphocytes. Using a protocol for intracellular staining of cytokines followed by fluorescence activating cell sorting (FACS) analysis, production of interleukin (IL)-2, IL-5 and IL-10 was detected in CD4(+)as well as in CD8(+)lymphocytes. Most notably, there was a definite increase in the expression of IL-10 in CD8(+) lymphocytes from patients with alveolar echinococcosis. The data support an important role of CD8(+) lymphocytes in the long persistence of the metacestode.

Zinc status in patients with alveolar echinococcosis is related to disease progression

Zinc is an essential trace element for immune function that plays a role in immune response against parasites. To determine a possible relationship between zinc level and disease status in alveolar echinococcosis (AE), we investigated serum concentrations of zinc, immunoglobulin (Ig)E, IgG, and C-reactive protein (CRP) in 40 AE patients and 20 controls. Patients were classified into three groups: group A: patients after curative surgery, group B: patients with stabilized disease, group C: patients with progressive disease. Patients showed significantly higher levels of IgE and IgG than controls. Amounts of IgE and IgG were related to disease severity, achieving highest levels in group C and lowest in group A. Zinc levels were comparable in patients and controls. However, there was an obvious association between zinc concentration and disease severity. Zinc was far below the normal range in group C (median 9.2 micromol/l) and significantly diminished compared to group B and controls. An inverse pattern was seen for CRP. In conclusion, lowered zinc concentration in progressive cases may be caused by enhanced immune activation but consumption of zinc by the growing parasite may also play a role. Furthermore, decreased zinc levels may contribute to the observed immunosuppression in AE.