Comparative analysis of host immune responses to Hydatid cyst in human and ovine hepatic cystic Echinococcosis.

BACKGROUND: Hydatid disease is caused by the larval stages of the canine tapeworm Echinococcus granulosus. It is one of the most critical helminthic diseases, representing worldwide public health and socio-economic concern. AIM: This study aimed to investigate the expression of apoptosis and immune response within hepatic tissues of humans and sheep infected with the Hydatid cyst. METHODS: Paraffin-embedded tissue was prepared from each tissue sample and used for histopathological examination by Haematoxylin- Eosin. Also, toluidine blue staining was used for mast cell detection, while an immunohistochemical study was performed to assess CD3 T lymphocytes, CD4 helper T lymphocytes, CD8 cytotoxic T lymphocytes, CD20 memory B lymphocytes, CD68 macrophage, and caspase-3 antibodies. RESULTS: The histological examination revealed significant changes, including the infiltration of inflammatory cells, predominantly lymphocytes with scattered giant cells, necrotic hepatic tissue, and fibrosis. Toluidine blue stain revealed a higher number of mast cells (5 cells/field) in humans compared to sheep (3.6 cells/field). The immunohistochemical analysis confirmed that the CD3 were the most predominant inflammatory cell in the hepatic tissue of humans (intensive 70%), and sheep (moderate 38.47%). Caspase-3 was observed in all samples in different grades and mostly in human liver tissue. CONCLUSION: This data could aid in recognizing immunological markers for differentiating disease progression, as well as enhance the understanding of local immune responses to cystic Echinococcosis (CE). The findings could provide preliminary data for future studies on immune responses associated with Hydatid cysts.

Identification of infiltrating immune cell subsets and heterogeneous macrophages in the lesion microenvironment of hepatic cystic echinococcosis patients with different cyst viability.

Human cystic echinococcosis (CE) is characterized by lesion microenvironment formation through gathering various immune cells, including macrophages. However, immune cell subsets and heterogeneous macrophages in CE lesion microenvironment are poorly defined. Massive infiltrating immune cells formed lesion microenvironment, among which CD4+T cells and CD19+B cells were predominant and CD68+ macrophages were more evident in patients with active cysts. Different degrees of liver fibrosis was observed in Peri-Lesion (PL) liver samples, which was more evident in patients with active cysts. Expression of both M1 and M2 macrophage markers was significantly increased in PL liver samples. Importantly, elevation of M1 macrophage markers was more obvious in patients with inactive cysts, whereas M2 macrophage markers represented dominant macrophage phenotype in patients with active cysts. Additionally, macrophage-derived MIF, TGF-ß1 and ECM1 were also expressed at higher level in CE lesion microenvironment of patients with active cysts. Moreover, MIF was evidently enhanced in the serum of hepatic CE patients, which was also predominant in patients with active cysts. Correlation analysis demonstrated positive correlation between expression of macrophage-derived cytokines and liver fibrosis degree. Heterogeneous macrophages may play significant roles in liver fibrosis of CE lesion microenvironment through producing pro-fibrogenic cytokines.

Agranulocytosis leads to intestinal Echinococcus multilocularis oncosphere invasion and hepatic metacestode development in naturally resistant Wistar rats.

Susceptibility to Echinococcus multilocularis infection considerably varies among intermediate (mostly rodents) and dead-end host species (e.g. humans and pig), in particular regarding intestinal oncosphere invasion and subsequent hepatic metacestode development. Wistar rats are highly resistant to infection and subsequent diseases upon oral inoculation with E. multilocularis eggs, however, after immunosuppressive treatment with dexamethasone, rats become susceptible. To address the role of the cellular innate immunity, Wistar rats were individually or combined depleted of natural killer (NK) cells, macrophages (MΦ) and granulocytes (polymorphonuclear cells, PMN) prior to E. multilocularis egg inoculation. Although NK cell and MΦ depletion did not alter the resistance status of rats, the majority of PMN-depleted animals developed liver metacestodes within 10 weeks, indicating that PMN are key players in preventing oncosphere migration and/or development in Wistar rats. In vitro studies indicated that resistance is not caused by neutrophil reactive oxygen species or NETosis. Also, light microscopical examinations of the small intestine showed that oral inoculation of E. multilocularis eggs does not elicit a mucosal neutrophil response, suggesting that the interaction of oncospheres and neutrophils may occur after the former have entered the peripheral blood. We suggest to consider granulocytes as mediators of resistance in more resistant species, such as humans.

Short communication: Efficacy of albendazole in Echinococcus multilocularis-infected mice depends on the functional immunity of the host.

Alveolar echinococcosis (AE) is a deadly parasitic disease that requires lifelong treatment with albendazole. Development of host immunity is pivotal with regard to the clinical outcome of AE, but its influence on conventional albendazole treatment is unknown. Using T-cell deficient athymic nude mice, we demonstrated that functional immunity is required for albendazole to be efficacious against murine AE. These results call for attention given the increasing number of immunocompromised patients with AE.

Fasciola hepatica coinfection modifies the morphological and immunological features of Echinococcus granulosus cysts in cattle.

Polyparasitism occurs when animals harbour multiple parasites concomitantly. It is a common occurrence but is generally understudied in wild and domestic animals. Fasciola hepatica and Echinococcus granulosus, which are helminths of ungulates, frequently coinfect cattle. The effects of this particular type of polyparasitism are not well documented. The metacestode of Echinococcus granulosus is surrounded by the adventitial layer, which constitutes the host immune response to the parasite. This layer in cattle is produced by a granulomatous reaction and is involved in echinococcal cyst (EC) fertility. Due to the systemic immune-modulating abilities of Fasciola hepatica, coinfection possibly generates a favourable environment for EC growth. A total of 203 Echinococcus granulosus sensu stricto cysts were found in 82 cattle, of which 42 ECs were found in 31 animals coinfected with Fasciola hepatica. The overall infection intensity was 3 cysts per animal. Coinfection with Fasciola hepatica decreased the mean infection intensity to 1.4 cysts per animal. Regarding EC size, coinfection resulted in smaller ECs (15.91 vs 22.09 mm), especially for infertile lung cysts. The adventitial layer of ECs in coinfected animals lacked lymphoid follicles and palisading macrophages, which are generally hallmarks of the granulomatous immune response. The ECs in coinfected animals had organized laminated layers, whereas those in animals without coinfection did not. Although coinfection was not statistically associated with EC fertility, we did not find fertile cysts in the livers of coinfected animals. We concluded that coinfection with Fasciola hepatica and Echinococcus granulosus has a detrimental effect on ECs, particularly infertile cysts.

Kupffer Cells: Important Participant of Hepatic Alveolar Echinococcosis.

Aims: Kupffer cells (KCs) are the liver-resident macrophages and play a leading role in the regulation of liver homeostasis in physiological conditions and in pathology. The study aims to investigate the anti-echinococcosis effect of KCs and the effects of hepatic stellate cells (HSCs) activation in the progression of liver fibrosis in hepatic alveolar echinococcosis (hepatic AE). Methods: Hematoxylin-eosin (H&E) and Masson staining were used to assess the pathological inflammatory changes and collagen deposition, respectively. Immunohistochemistry and qRT-PCR were used to detect the number of aggregates of KCs, the expression of cytokines and activation of HSCs. Results: In the close group, H&E staining showed that the normal lobular structure was destroyed and inflammatory infiltration around the lesion could be observed, and Masson staining showed that blue collagen fibers were clearly deposited near the portal area. IHC showed that KCs surface markers CD68 and CD163, cytokine iNOS and Arg-1 were positively expressed in the vicinity of inflammatory lesions. qRT-PCR indicated that TNF-α, IL-10, and TGF-ß1 secreted by KCs were significantly higher than those in the distance group (P < 0.01). It is worth noticing that the expression levels of anti-inflammatory cytokines were slightly higher than that of pro-inflammatory cytokines. Both IHC and qRT-PCR results showed that HSCs activation markers, the expression of α-SMA and Desmin significantly increased. Conclusions: Our research indicates that KCs have immune-protective effect of anti-echinococcosis and promote liver fiber repair, and it also suggests that they have potential therapeutic value for patients with hepatic AE.

Immune Exhaustion of T Cells in Alveolar Echinococcosis Patients and Its Reversal by Blocking Checkpoint Receptor TIGIT in a Murine Model.

BACKGROUND AND AIMS: The cestode Echinococcus multilocularis infection, a serious health problem worldwide, causes alveolar echinococcosis (AE), a tumor-like disease predominantly located in the liver and able to spread to any organs. Until now, there have been few studies that explore how T-cell exhaustion contributes to the parasite's escape from immune attack and how it might be reversed. APPROACH AND RESULTS: In this study, we found that liver T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) expression was significantly enhanced and positively correlated with lesion activity in AE patients. High TIGIT expression in both liver-infiltrating and blood T cells was associated with their functional exhaustion, and its ligand CD155 was highly expressed by hepatocytes surrounding the infiltrating lymphocytes. In co-culture experiments using human blood T cells and hepatic cell line HL-7702, CD155 induced functional impairment of TIGIT+ T cells, and in vitro blockade with TIGIT antibody restored the function of AE patients' T cells. Similar TIGIT-related functional exhaustion of hepatic T cells and an abundant CD155 expression on hepatocytes were observed in E. multilocularis-infected mice. Importantly, in vivo blocking TIGIT prevented T-cell exhaustion and inhibited disease progression in E. multilocularis-infected mice. Mechanistically, CD4+ T cells were totally and CD8+ T cells partially required for anti-TIGIT-induced regression of parasite growth in mice. CONCLUSIONS: This study demonstrates that E. multilocularis can induce T-cell exhaustion through inhibitory receptor TIGIT, and that blocking this checkpoint may reverse the functional impairment of T cells and represent a possible approach to immunotherapy against AE.

Degree of calcification and cyst activity in hepatic cystic echinococcosis in humans.

To evaluate the relationship between cyst activity and calcification degree in cystic echinococcosis (CE) in humans, 99 hepatic cysts at successive stages of involution, surgically excised from 72 Sardinian patients, have been analyzed. Cysts were classified into 4 groups according to calcification extent: CALC 0 (no calcification); CALC 1 (scattered punctate calcifications); CALC 2 (large coarse segmental/partial calcifications); CALC 3 (complete or nearly complete circumferential ring of calcification up to thick wall of osseous consistency/calcified content of cyst). In addition the possible correlation with antibody response has been explored analyzing IgG1, IgG4 and IgE produced against somatic PSCAg. Results showed that calcification is not restricted to the inactive WHO cyst types CE4 and CE5, but occurs to a varying extent in all morphotypes of metacestode, from active classic unilocular or multivesicular cysts to the more complicated and highly degenerate stages, where cyst wall appears massively calcified. Prevalence of calcification increases with progression of cyst degenerative process, but is not synonymous with parasite inactivity and can be misleading as signs of calcification may coexist with still metabolically active cysts. On the contrary, detection of entirely firmly solidified content seems a reliable indication of cyst inactivity. IgG4 is the dominant isotype associated particularly with the evolutive phase. Positive rates and OD levels, higher in active vs inactive stages, are stable or increase slightly in weakly and moderately calcified cysts (CALC 1/CALC 2), compared to non-calcified ones (CALC 0), strongly decreasing in highly calcified forms (CALC 3). In conclusion, evaluation of calcification extent may be pertinent for staging CE, and immunological tests, particularly for IgG4, and IgE may help to better define cyst activity.

[Pulmonary granuloma in an immunodepressed patient]. / Un granulome pulmonaire chez une patiente immunodéprimée.

INTRODUCTION: Pulmonary alveolar echinococcosis is a rare but potentially severe condition. CASE REPORT: We report the case of a 50-year-old woman suffering from pulmonary alveolar echinococcosis who had had a renal transplant for polycystic liver and kidney disease. A lung opacity was identified radiologically in May 2013. Both broncho-alveolar lavage and bronchial biopsy were uninformative. In January 2014, a follow up CT-scan showed the opacity to be enlarging. A surgical biopsy revealed a giant cell epithelioid granuloma with caseous necrosis suggesting a diagnosis of pulmonary tuberculosis. Antituberculous treatment was started but cultures remained negative. A histological revue was therefore requested in March 2014. This suggested bronchocentric granulmatosis, possibly associated with echinococcosis. This hypothesis was finally confirmed serologically. Treatment for alveolar echinococcosis was begun in June 2014 after consultation with the national reference centre for parasitology. CONCLUSION: Outside endemic areas and in the absence of hepatic involvement pulmonary alveolar echinococcosis can be difficult to diagnose. This case report focuses on the diagnostic criteria and treatment.

Case-series study of hepatic echinococcal cysts in Serbia: viability of scolices, seropositivity and epidemiological characteristics.

Cystic echinococcosis (CE) is an endemic helminthic disease caused by infection with Echinococcus granulosus metacestodes. Although CE is endemic in the Balkan region, the exact epidemiology remains unknown. We conducted a case-series study with the aim of evaluating the correlation between seropositivity, socio-epidemiological data, pre-operative treatment with albendazole and viability of protoscolices in human hepatic hydatid cysts. Consecutive patients with hepatic CE underwent surgery to extract E. granulosis cysts. The viability of protoscolices was measured by their ability to absorb 0.1% eosin. Socio-epidemiological data were collected and serological testing was performed. In the present study, 38 patients (28 adults and 10 children) with hepatic CE were treated surgically. The scolex viability test was positive in 30/38 (79%) samples. All patients with non-viable cysts had seronegative results. The viability test was positive in 11/12 (91.6%) adult patients with pre-operative albendazole treatment and in 9/10 (90%) children. Statistically more patients were from an urban area compared with a rural area (65.8% vs. 15.7%). The increasing number of stray dogs shedding E. granulosus eggs in urban public areas in the Balkans might be the reason for the significant difference in the rate of infection between urban and rural areas in the present study. In addition, uncontrolled slaughtering of livestock, common in rural settlements, and feeding the infected viscera to dogs, favour the maintenance of the parasite cycle. We believe that the results of our study will encourage physicians, veterinarians and health authorities to initiate a programme to prevent and control CE in the Balkan region.

[Expression of follicular helper T cells in peripheral blood of patients with hepatic echinococcosis].

OBJECTIVE: To detect the expression of follicuLar helper T cells (Tfh) and interleukin-21 (IL-21) in the peripheral blood of patients with hepatic echinococcosis and healthy controls, so as to explore the associations of Tfh and IL-21 expression with the progression of hepatic echinococcosis. METHODS: Fifty cases of hepatic echinococcosis and healthy controls were collected from Qinghai Provincial People's Hospital, respectively. Flow cytometry was used to detect the expression of Tfh cells in the peripheral blood of hepatic echinococcosis patients and healthy controls, and enzyme-linked immunosorbent assay (ELISA) was used to detect serum IL-21 expression in hepatic echinococcosis patients and healthy controls. The correlation between Tfh cell expression and serum IL-21 level was examined in the patients with hepatic echinococcosis. RESULTS: Flow cytometry detected a higher percentage of CD4+CXCR5+ T cells (18.49% ± 5.67% vs. 16.18% ± 4.04%, P < 0.05), CD4+CXCR5+PD-1+ T cells (4.94% ± 1.91% vs. 2.29% ± 0.79%, P < 0.05) and CD4+CXCR5+ICOS+PD-1+ T cells (30.93% ± 24.10% vs. 21.07% ± 14.25%, P < 0.05) in hepatic echinococcosis patients than in healthy controls, and no significant difference was seen in the percentage of CD4+CRCR5+ICOS+ T cells between the patients and controls (0.29% ± 0.32% vs. 0.25% ± 0.31%, P > 0.05) . The serum IL-21 level was significantly higher in the patients with hepatic echinococcosis than in healthy controls ([ 293.35 ± 2 03.65) pg/mL vs. (192.72 ± 70.09) pg/mL, P < 0.05]; however, there was no correlation between the Tfh cell expression and serum IL-21 level in patients with hepatic echinococcosis (P > 0.05). CONCLUSIONS: The expression of peripheral blood Tfh cells and serum IL-21 is elevated in patients with hepatic echinococcosis, and Tfh cells and IL-21 may contribute to the progression of hepatic echinococcosis.

Improved experimental model of hepatic cystic hydatid disease resembling natural infection route with stable growing dynamics and immune reaction.

AIM: To investigate a safer way to set up the disease model of cystic echinococcosis without contamination risk and develop a novel experimental murine model of hepatic cystic echinococcosis. METHODS: C57B/6 mice were injected with human protoscolices of three different concentrations via the portal vein. The mice were followed for 10 mo by ultrasound, gross anatomy, and pathological and immunological examinations. The protoscolex migration in the portal vein, hydatid cyst growth, host immune reaction, and hepatic histopathology were examined periodically. RESULTS: The infection rates in the mice in the high, medium, and low concentration groups were 90%, 100%, and 63.6%, respectively. The protoscolices migrated in the portal vein with blood flow, settled in the liver, and developed into orthotopic hepatic hydatid cysts, resembling the natural infection route and course. CONCLUSION: We have established an improved experimental model of hepatic cystic echinococcosis with low biohazard risk but stable growing dynamics and immune reaction. It is especially useful for new anti-parasite medication trials against hydatid disease.

T-cell tolerance and exhaustion in the clearance of Echinococcus multilocularis: role of inoculum size in a quantitative hepatic experimental model.

The local immune mechanisms responsible for either self-healing or sustained chronic infection are not clear, in the development of E. multilocularis larvae. Here, we developed a suitable experimental model that mimics naturally infected livers, according to the parasite load. We demonstrated that local cellular immunity and fibrogenesis are actually protective and fully able to limit metacestode growth in the liver of low or medium dose-infected mice (LDG or MDG), or even to clear it, while impairment of cellular immunity is followed by a more rapid and severe course of the disease in high dose-infected mice (HDG). And recruitment and/ or proliferation of memory T cells (including CD4 Tem, CD8 Tcm and CD8 Tem) and imbalance of T1/T2/T17/Treg-type T cells in liver were not only associated with clearance of the parasite infection in LDG, but also with increased hepatic injury in HDG; in particular the dual role of CD8 T cells depending on the parasite load and the various stages of metacestode growth. Besides, we first demonstrate the association between LAG3- or 2B4-expressing T cells exhaustion and HD inocula in late stages. Our quantitative experimental model appears fully appropriate to study immunomodulation as a therapeutic strategy for patients with Alveolar Echinococcosis.

Optimized dexamethasone immunosuppression enables Echinococcus multilocularis liver establishment after oral egg inoculation in a rat model.

Comparable with immunocompetent humans, rats are considered highly resistant to Echinococcus multilocularis oncosphere invasion, both in nature and after experimental oral inoculation with eggs. Pharmacological immunosuppression with dexamethasone (DMX) was shown to abrogate the resistance of RccHan™:WIST rats, but due to weight losses >20%, many animals had to be excluded from previous experiments. The optimized DXM (Dexafort, MSD Animal Health, Germany) dosage regime presented in this study (each animal: 750 µg DXM at day -13 and 600 µg DXM at day -9 before inoculation) applied subcutaneously to RccHan™:WIST rats, resulted in weight losses ≤20%, but led to liver alveolar echinococcosis (AE) in all eight inoculated animals. Untreated control groups (each n = 8) including RccHan™:WIST (Wistar) and F344/DuCrl (Fischer-344) rats showed no parasite establishment. Antibodies against E. multilocularis metacestode vesicle fluid were present in 7/8 of the infected RccHan™:WIST rats 70 days after inoculation but in none of the control animals. Serology can therefore be used to diagnose AE. This optimized animal model enables a high infection rate in rats and may be applied in future immunological and experimental studies.

Immunology of Alveolar and Cystic Echinococcosis (AE and CE).

Cystic and alveolar echinococcosis are severe chronic helminthic diseases caused by the cystic growth or the intrahepatic tumour-like growth of the metacestode of Echinococcus granulosus or Echinococcus multilocularis, respectively. Both parasites have evolved sophisticated strategies to escape host immune responses, mainly by manipulating and directing this immune response towards anergy and/or tolerance. Recent research studies have revealed a number of respective immunoregulatory mechanisms related to macrophages and dendritic cell as well as T cell activities (regulatory T cells, Tregs). A better understanding of this complex parasite-host relationship, and the elucidation of specific crucial events that lead to disease, represents targets towards the development of novel treatment strategies and options.

Biochemical Characterization of Echinococcus multilocularis Antigen B3 Reveals Insight into Adaptation and Maintenance of Parasitic Homeostasis at the Host-Parasite Interface.

Alveolar echinococcosis (AE) caused by Echinococcus multilocularis metacestode is frequently associated with deleterious zoonotic helminthiasis. The growth patterns and morphological features of AE, such as invasion of the liver parenchyme and multiplication into multivesiculated masses, are similar to those of malignant tumors. AE has been increasingly detected in several regions of Europe, North America, Central Asia, and northwestern China. An isoform of E. multilocularis antigen B3 (EmAgB3) shows a specific immunoreactivity against patient sera of active-stage AE, suggesting that EmAgB3 might play important roles during adaptation of the parasite to hosts. However, expression patterns and biochemical properties of EmAgB3 remained elusive. The protein profile and nature of component proteins of E. multilocularis hydatid fluid (EmHF) have never been addressed. In this study, we conducted proteome analysis of EmHF of AE cysts harvested from immunocompetent mice. We observed the molecular and biochemical properties of EmAgB3, including differential transcription patterns of paralogous genes, macromolecular protein status by self-assembly, distinct oligomeric states according to individual anatomical compartments of the worm, and hydrophobic ligand-binding protein activity. We also demonstrated tissue expression patterns of EmAgB3 transcript and protein. EmAgB3 might participate in immune response and recruitment of essential host lipids at the host-parasite interface. Our results might contribute to an in depth understanding of the biophysical and biological features of EmAgB3, thus providing insights into the design of novel targets to control AE.

A Synchronous Occurrence of Hepatocellular Carcinoma and Echinoccocal Liver Cyst - Can Parasite Promote Carcinogenesis? Literature Review and Classification Proposal.

Concomitant presence of hydatid cyst and hepatocellular carcinoma is a very rare clinical scenario especially in a previously non-diseased liver. Including our case here reported, there are 12 cases of synchronous HCC and hydatid cyst found in the scientific literature and 3 of them were found in a patient with non-diseased liver. We provide detailed review of all reported cases with additional highlights on etiology, pathogenesis, diagnosis, treatment and outcomes of both HCC and echinococcal disease. Although there is a small number of patients, possible relation between these 2 liver lesions should be investigated and standardized classification should be established. This will help us to understand the nature of HCC carcinogenesis, identify diagnostic features of liver lesions and choose the most appropriate type of treatment.

Investigation of the use of serology and ultrasonography to detect hepatic cystic echinococcosis in Heilongjiang, China, using a Bayesian framework.

BACKGROUND: Cystic echinococcosis (CE) is a public health problem in China. However, the prevalence and incidence of CE in Heilongjiang province is still poorly understood. Because there is no perfect gold standard, evaluation of ultrasound (US) and serological methods have been limited. This study evaluated the use of these two diagnostic methods for the diagnosis of CE in suspected cases. METHODS: A total of 522 suspected hepatic CE patients, as well as their demographic and clinical features were collected and detected by immunoglobulin (IgG)-ELISA and US. The marginal posterior densities of sensitivity and specificity for both tests, and the prevalence of hepatic CE amongst participants, were estimated from the product of the likelihood function of observed and latent data by a Bayesian framework. RESULTS: Most of the patients were from rural areas. The most common symptom was upper abdominal pain. The antibody-positive proportion determined by IgG-ELISA was 24.33% (127/522), significantly higher than with US examination (17.24%, 90/522). Bayesian analysis indicated that the estimated prevalence of CE amongst suspected cases was 17.70% (95% credible interval: 14.23-21.54%). The sensitivity and specificity of the ELISA test were 92.63% and 90.37%, and that of US were 93.05% and 98.44%, respectively. Among US-confirmed hepatic CE cases, the male to female ratio was 0.46 and the peak age group was 40-49 years. CONCLUSIONS: The results of the current study demonstrate that CE is present in Heilongjiang province. They also suggest that, whilst ultrasonography appears to be the detection modality of choice, serology may have a use for detection of infection in individuals suspected to be infected. This may have applications for surveillance within the province.

Synthesis and Antigenicity against Human Sera of a Biotin-Labeled Oligosaccharide Portion of a Glycosphingolipid from the Parasite Echinococcus multilocularis.

Synthesis of a biotinylated analog of the carbohydrate portion of a glycosphingolipid from the parasite Echinococcus multilocularis has been achieved. We synthesized ß-D-Galp-(1→6)-ß-D-Galp-(1→6)-[α-L-Fucp-(1→3)]-ß-D-Galp-(1→R: biotin probe) (1) and compared the antigenicity by an enzyme linked immunosorbent assay (ELISA) with biotinylated trisaccharide α-D-Galp-(1→4)-ß-D-Galp-(1→3)-α-D-Galp-(1→R: biotin probe) (F), which has been shown to have significant antigenicity. Both of the oligosaccharides reacted with sera of alveolar echinococcosis (AE) patients, but showed different reactivity. Among the 60 sera of AE patients, more sera reacted with the linear sequence Galα1→4Galß1→3GalNAcα1→R of oligosaccharide (F) than for branched compound 1. Some sera showed high specificity to one of the compound, indicating that the antibodies in the sera of AE patients differ in their specificity to recognize carbohydrate sequences of glycosphingolipids. Our results demonstrate that both of the biotinylated oligosaccharides 1 and F have good serodiagnostic potential and are complementary to detect infections caused by the parasite Echinococcus multilocularis.

Immunoregulation in larval Echinococcus multilocularis infection.

Alveolar echinococcosis (AE) is a clinically very severe zoonotic helminthic disease, characterized by a chronic progressive hepatic damage caused by the continuous proliferation of the larval stage (metacestode) of Echinococcus multilocularis. The proliferative potential of the parasite metacestode tissue is dependent on the nature/function of the periparasitic immune-mediated processes of the host. Immune tolerance and/or down-regulation of immunity are a marked characteristic increasingly observed when disease develops towards its chronic (late) stage of infection. In this context, explorative studies have clearly shown that T regulatory (Treg) cells play an important role in modulating and orchestrating inflammatory/immune reactions in AE, yielding a largely Th2-biased response, and finally allowing thus long-term parasite survival, proliferation and maturation. AE is fatal if not treated appropriately, but the current benzimidazole chemotherapy is far from optimal, and novel options for control are needed. Future research should focus on the elucidation of the crucial immunological events that lead to anergy in AE, and focus on providing a scientific basis for the development of novel and more effective immunotherapeutical options to support cure AE by abrogating anergy, anticipating also that a combination of immuno- and chemotherapy could provide a synergistic therapeutical effect.