Eosinophil activation status, cytokines and liver fibrosis in Schistosoma mansoni infected patients

Effects of Immunization with Recombinant Schistosoma mansoni Enzymes AK and HGPRT: Murine Infection Control

Schistosomiasis is one of the most important human helminthiases worldwide. Praziquantel is the current treatment, and no vaccine is available until the present. Thus, the presented study aimed to evaluate the immunization effects with recombinant Schistosoma mansoni enzymes: Adenosine Kinase (AK) and Hypoxanthine-Guanine Phosphoribosyltransferase (HGPRT), as well as a MIX of the two enzymes. Female Balb/c mice were immunized in three doses, and 15 days after the last immunization, animals were infected with S. mansoni. Our results showed that the group MIX presented a reduction in the eggs in feces by 30.74% and 29%, respectively, in the adult worms. The groups AK, HGPRT and MIX could produce IgG1 antibodies, and the groups AK and MIX produced IgE antibodies anti-enzymes and anti-S. mansoni total proteins. The groups AK, HGPRT and MIX induced a reduction in the eosinophils in the peritoneal cavity. Besides, the group AK showed a decrease in the number of hepatic granulomas (41.81%) and the eggs present in the liver (42.30%). Therefore, it suggests that immunization with these enzymes can contribute to schistosomiasis control, as well as help to modulate experimental infection inducing a reduction of physiopathology in the disease.

In vitro and in vivo evaluation of Bacillus clausii against Schistosoma mansoni

Experimental studies and clinical trials have been showing that probiotics are promising in the prevention and control of parasite infections. B. clausii, obtained from Enterogermina®, was cultured to obtain cell-free culture supernatant (CFS) and spores to evaluate its schistosomicidal effect in vitro and in vivo against Schistosoma mansoni, respectively. For in vitro and in vivo analysis mice were infected with 120 and 50 cercariae, respectively. Couples of adult worms, recovered on day 45 of infection, were exposed to CFS. The in vivo assay was performed for 100 days, where all animals were infected on the 30^th day. Four experimental groups were formed, as follows: G1 - Saline solution from the 1^st until the 100^th day; G2 - B. clausii from the 1^st until the 100^th day; G3 - B. clausii from the 68^th day (onset of oviposition) until the 100^th day and G4 - PZQ (50 mg/Kg) from the 75^th until the 79^th day. In vitro, CFS of B. clausii does not caused mortality nor changed the motility on S. mansoni adult worms. G2 and G3 showed reduction of the 68.58 and 44.25% in the number of eggs eliminated in the feces and 34.29 and 53.6% and 22.8 and 48.49% the number of eggs trapped in the liver and intestine, respectively. Furthermore, in both therapeutic regimens G2 and G3, B. clausii increased the percentage of dead eggs in the intestinal tissue. B. clausii CFS, in vitro, does not showed action against S. mansoni and that treatment with B. clausii spores modulates favorably the parasitological parameters in the experimental infection of S. mansoni.

Hepatosplenic Protective Actions of Spirulina platensis and Matcha Green Tea Against Schistosoma mansoni Infection in Mice via Antioxidative and Anti-inflammatory Mechanisms

Schistosomiasis, a major parasitic illness, has high morbidity and negative financial effects in subtropical and tropical countries, including Egypt. The present study investigated the therapeutic effects of Spirulina platensis (SP) and matcha green tea (MGT) in Schistosoma mansoni-infected mice combined with tracing their possible antioxidant and anti-inflammatory impacts and their protective potency. A total of 60 Swiss albino mice were randomly allocated into six groups (n = 10): control group (CNT, received normal saline); SP–MGT group [received oral SP (3 g/kg bodyweight/day) plus MGT (3 g/kg bodyweight/day)]; S. mansoni group (infected with S. mansoni cercariae, 100 ± 10/mouse, using the tail immersion method); SP-infected group (infected with S. mansoni and received oral SP); MGT-infected group (received oral MGT after S. mansoni infection); and SP–MGT-infected group (received combined treatment of SP and MGT after S. mansoni infection). Treatment with SP and MGT started 4 weeks after S. mansoni infection and ended 10 weeks after. SP and MGT treatment (SP-infected and MGT-infected groups) and the combined treatment (SP–MGT-infected group) minimized the hepatic damage induced by S. mansoni; circulating alanine aminotransferase and aspartate transaminase decreased, and total protein, albumin, and globulin serum levels increased. The serum level of malondialdehyde significantly declined, and catalase, glutathione peroxidase, superoxide dismutase, and total antioxidant capacity increased in SP-infected, MGT-infected, and SP–MGT-infected groups compared with the infected group. Co-administration of SP and MGT reduced serum cytokine levels (tumor necrosis factor-alpha, interferon-gamma, and interleukin-13) and increased interleukin-10 levels after S. mansoni infection compared with the infected group. Moreover, treatment with SP and/or MGT decreased the number of granulomas in hepatic and splenic tissues compared with the infected group. Collectively, our results suggest that combined SP and MGT treatment is effective for S. mansoni infection. Liver and spleen tissue alterations were improved, the antioxidant systems were stimulated, and the inflammatory response was suppressed. Further research is recommended to investigate the mechanisms of the combined SP and MGT treatment effects to facilitate the development of novel therapies against this disease.

Schistosomiasis Morbidity Hotspots: Roles of the Human Host, the Parasite and Their Interface in the Development of Severe Morbidity

Schistosomiasis is the second most important human parasitic disease in terms of socioeconomic impact, causing great morbidity and mortality, predominantly across the African continent. For intestinal schistosomiasis, severe morbidity manifests as periportal fibrosis (PPF) in which large tracts of macro-fibrosis of the liver, visible by ultrasound, can occlude the main portal vein leading to portal hypertension (PHT), sequelae such as ascites and collateral vasculature, and ultimately fatalities. For urogenital schistosomiasis, severe morbidity manifests as pathology throughout the urinary system and genitals, and is a definitive cause of squamous cell bladder carcinoma. Preventative chemotherapy (PC) programmes, delivered through mass drug administration (MDA) of praziquantel (PZQ), have been at the forefront of schistosomiasis control programmes in sub-Saharan Africa since their commencement in Uganda in 2003. However, despite many successes, 'biological hotspots' (as distinct from 'operational hotspots') of both persistent high transmission and morbidity remain. In some areas, this failure to gain control of schistosomiasis has devastating consequences, with not only persistently high infection intensities, but both "subtle" and severe morbidity remaining prevalent. These hotspots highlight the requirement to revisit research into severe morbidity and its mechanisms, a topic that has been out of favor during times of PC implementation. Indeed, the focality and spatially-structured epidemiology of schistosomiasis, its transmission persistence and the morbidity induced, has long suggested that gene-environmental-interactions playing out at the host-parasite interface are crucial. Here we review evidence of potential unique parasite factors, host factors, and their gene-environmental interactions in terms of explaining differential morbidity profiles in the human host. We then take the situation of schistosomiasis mansoni within the Albertine region of Uganda as a case study in terms of elucidating the factors behind the severe morbidity observed and the avenues and directions for future research currently underway within a new research and clinical trial programme (FibroScHot).

The immunomodulatory activity of Chenopodium ambrosioides reduces the parasite burden and hepatic granulomatous inflammation in Schistosoma mansoni-infection

ETHNOPHARMACOLOGICAL RELEVANCE

Folk medicine reports have described the use of Chenopodium ambrosioides as an anti-inflammatory, analgesic, and anthelmintic herb. These effects, including its activity against intestinal worms, are already scientifically observed. However, the immunological mechanisms of this species in the treatment of Schistosoma mansoni infection are unknown.

AIM OF THE STUDY

To evaluate the immunological and anti-Schistosoma mansoni effects of a crude Chenopodium ambrosioides hydro-alcoholic extract (HCE).

MATERIALS AND METHODS

For the in vitro analysis, cercariae and adult worms were exposed to different concentrations (0 to 10,000 μg/mL) of the HCE. For the in vivo evaluation, Swiss mice were infected with 50 cercariae of S. mansoni and separated into groups according to treatment as follows: a negative control (without treatment), a positive control (treated with Praziquantel®), HCE1 Group (treated with HCE during the cutaneous phase), HCE2 Group (treated with HCE during the lung phase), HCE3 Group (treated with HCE during the young worm phase), and HCE4 Group (treated with HCE during the adult worm phase). The animals treated with HCE received daily doses of 50 mg/kg, by gavage, for seven days, corresponding to the different developmental stages of S. mansoni. For comparison, a clean control group (uninfected and untreated) was also included. All animals were euthanized 60 days post-infection to allow the following assessments to be performed: a complete blood cells count, counts of eggs in the feces and liver, the quantification of cytokines and IgE levels, histopathological evaluations of the livers, and the analysis of inflammatory mediators.

RESULTS

HCE treatment increased the mortality of cercariae and adult worms in vitro. The HCE treatment in vivo reduced the eggs in feces and liver. The number and area of liver granulomas, independent of the phase of treatment, were also reduced. The treatment with HCE reduced the percentage of circulating eosinophils, IgE, IFN-γ, TNF-α, and IL-4. In contrast, the treatment with the HCE, dependent on the phase, increased IL-10 levels and the number of peritoneal and bone marrow cells, mainly of T lymphocytes, B lymphocytes, and macrophages. This effect could be due to secondary compounds presents in this extract, such as kaempferol, quercetin and derivatives.

CONCLUSIONS

This study demonstrates that Chenopodium ambrosioides has antiparasitic and immunomodulatory activity against the different phases of schistosomiasis, reducing the granulomatous inflammatory profile caused by the infection and, consequently, improving the disease prognosis.

Eosinophil-Mediated Immune Control of Adult Filarial Nematode Infection Can Proceed in the Absence of IL-4 Receptor Signaling

Immunity to chronic filarial worm infection is apparent in IL-4Rα–deficient mice.

Delayed immunity in IL-4Rα^−/− mice is due to suboptimal tissue eosinophilia.

Eosinophil recruitment in the absence of IL-4R signaling requires CCR3 and IL-5.

Helminth infections are accompanied by eosinophilia in parasitized tissues. Eosinophils are effectors of immunity to tissue helminths. We previously reported that in the context of experimental filarial nematode infection, optimum tissue eosinophil recruitment was coordinated by local macrophage populations following IL-4R–dependent in situ proliferation and alternative activation. However, in the current study, we identify that control of chronic adult filarial worm infection is evident in IL-4Rα–deficient (IL-4Rα^−/−) mice, whereby the majority of infections do not achieve patency. An associated residual eosinophilia was apparent in infected IL-4Rα^−/− mice. By treating IL-4Rα^−/− mice serially with anti-CCR3 Ab or introducing a compound deficiency in CCR3 within IL-4Rα^−/− mice, residual eosinophilia was ablated, and susceptibility to chronic adult Brugia malayi infection was established, promoting a functional role for CCR3-dependent eosinophil influx in immune control in the absence of IL-4/IL-13–dependent immune mechanisms. We investigated additional cytokine signals involved in residual eosinophilia in the absence IL-4Rα signaling and defined that IL-4Rα^−/−/IL-5^−/− double-knockout mice displayed significant eosinophil deficiency compared with IL-4Rα^−/− mice and were susceptible to chronic fecund adult filarial infections. Contrastingly, there was no evidence that either IL-4R–dependent or IL-4R–independent/CCR3/IL-5–dependent immunity influenced B. malayi microfilarial loads in the blood. Our data demonstrate multiplicity of Th2-cytokine control of eosinophil tissue recruitment during chronic filarial infection and that IL-4R–independent/IL-5– and CCR3-dependent pathways are sufficient to control filarial adult infection via an eosinophil-dependent effector response prior to patency.

Eosinophils and Macrophages within the Th2-Induced Granuloma: Balancing Killing and Healing in a Tight Space

Granuloma formation is a key host immune response generated to confine invading pathogens and limit extensive host damage. It consists of an accumulation of host immune cells around a pathogen. This host response has been extensively studied in the context of inflammatory diseases. However, there is much less known about Th2-type granulomas generated in response to parasitic worms. Based on in vitro data, innate immune cells within the granuloma are thought to immobilize and kill parasites but also act to repair damaged tissue. Understanding this dual function is key. The two billion people and many livestock/wild animals infected with helminths demonstrate that granulomas are not effective at clearing infection. However, the lack of high mortality highlights their importance in ensuring that parasite migration/tissue damage is restricted and wound healing is effective. In this review, we define two key cellular players (macrophages and eosinophils) and their associated molecular players involved in Th2 granuloma function. To date, the underlying mechanisms remain poorly understood, which is in part due to a lack of conclusive studies. Most have been performed in vitro rather than in vivo, using cells that have not been obtained from granulomas. Experiments using genetically modified mouse strains and/or antibody/chemical-mediated cell depletion have also generated conflicting results depending on the model. We discuss the caveats of previous studies and the new tools available that will help fill the gaps in our knowledge and allow a better understanding of the balance between immune killing and healing.

Schistosome infection and its effect on pulmonary circulation

Schistosomiasis is the most common parasitic disease associated with pulmonary hypertension. It induces remodelling via complex inflammatory processes, which eventually produce the clinical manifestation of pulmonary hypertension. The pulmonary hypertension shows clinical signs and symptoms that are not distinguishable from other forms of pulmonary arterial hypertension.

Host Regulators of Liver Fibrosis During Human Schistosomiasis

Liver fibrosis is a wound-healing process purposely aimed at restoring organ integrity after severe injury caused by autoimmune reactions, mechanical stress or infections. The uncontrolled solicitation of this process is pathogenic and a pathognomonic feature of diseases like hepatosplenic schistosomiasis where exacerbated liver fibrosis is centrally positioned among the drivers of the disease morbidity and mortality. Intriguingly, however, liver fibrosis occurs and progresses dissimilarly in schistosomiasis-diseased individuals with the same egg burden and biosocial features including age, duration of residence in the endemic site and gender. This suggests that parasite-independent and currently poorly defined host intrinsic factors might play a defining role in the regulation of liver fibrosis, the hallmark of morbidity, during schistosomiasis. In this review, we therefore provide a comprehensive overview of all known host candidate regulators of liver fibrosis reported in the context of human schistosomiasis.

Anti-Inflammatory Properties of Menthol and Menthone in Schistosoma mansoni Infection

Schistosomiasis is a parasitic disease caused by several species of trematode worms and it is believed that more than 261 million people are affected worldwide. New drug development has become essential because there is a risk of the parasite becoming resistant to Praziquantel, the only drug available for this infection. This study evaluated parasitological, immunological and histological parameters in mice infected with Schistosoma mansoni and treated with an herbal commercial medicine. This drug consists of menthol (30-55%) and menthone (14-32%). A 60 day treatment regimen with the herbal medicine decreased the number of S. mansoni eggs in the feces, liver, and intestine and reduced the number of hepatic granulomas. We observed a reduction of 84% in blood eosinophilia and a decrease in the IL-4 and IL-10 blood levels after treatment. Therefore, we propose that schistosomiasis treatment with this herbal medicine for 60 days has an immunomodulatory and anti-inflammatory action in this animal model for schistosomiasis thus contributing to the decrease in physio pathological effects caused by S. mansoni infection.

Fasciola hepatica induces eosinophil apoptosis in the migratory and biliary stages of infection in sheep

The aim of the present work was to evaluate the number of apoptotic eosinophils in the livers of sheep experimentally infected with Fasciola hepatica during the migratory and biliary stages of infection. Four groups (n=5) of sheep were used; groups 1-3 were orally infected with 200 metacercariae (mc) and sacrificed at 8 and 28 days post-infection (dpi), and 17 weeks post-infection (wpi), respectively. Group 4 was used as an uninfected control. Apoptosis was detected using immunohistochemistry with a polyclonal antibody against anti-active caspase-3, and transmission electron microscopy (TEM). Eosinophils were identified using the Hansel stain in serial sections for caspase-3, and by ultrastructural features using TEM. At 8 and 28 dpi, numerous caspase-3(+) eosinophils were mainly found at the periphery of acute hepatic necrotic foci. The percentage of caspase -3(+) apoptotic eosinophils in the periphery of necrotic foci was high (46.1-53.9) at 8 and 28 dpi, respectively, and decreased in granulomas found at 28 dpi (6%). Transmission electron microscopy confirmed the presence of apoptotic eosinophils in hepatic lesions at 8 and 28 dpi. At 17 wpi, apoptotic eosinophils were detected in the infiltrate surrounding some enlarged bile ducts containing adult flukes. This is the first report of apoptosis induced by F. hepatica in sheep and the first study reporting apoptosis in eosinophils in hepatic inflammatory infiltrates in vivo. The high number of apoptotic eosinophils in acute necrotic tracts during the migratory and biliary stages of infection suggests that eosinophil apoptosis may play a role in F. hepatica survival during different stages of infection.

A boswellic acid-containing extract ameliorates schistosomiasis liver granuloma and fibrosis through regulating NF-κB signaling in mice

Boswellic acid (BA)-containing extracts such as BSE have anti-inflammatory and immunomodulatory activity. In chronic schistosomiasis, the hepatic granuloma and fibrosis induced by egg deposition in the liver is the most serious pathological manifestations. However, little is known regarding the role of BAs in Schistosoma japonicum (S. japonicum) egg-induced liver granuloma and fibrosis. In order to investigate the effect of a water-soluble complex preparation of BSE, BSE-CD, on S. japonicum egg-induced liver pathology, liver granuloma and fibrosis were induced by infecting C57BL/6 mice with 18-22 cercariae of S. japonicum. S. japonicum cercariae infected mice were injected with BSE-CD at the onset of egg granuloma formation (early phase BSE-CD treatment after 4 weeks infection) or after the formation of liver fibrosis (late phase BSE-CD treatment after 7 weeks infection). Our data show that treatment of infected mice with BSE-CD significantly reduced both the extent of hepatic granuloma and fibrosis. Consistent with an inhibition of NF-κB signaling as evidenced by reduced IκB kinase (IKK) activation, the mRNA expression of VEGF (vascular endothelial growth factor, VEGF), TNF-α (tumor necrosis factor-alpha TNF-α) and MCP-1 (monocyte chemotactic protein 1, MCP-1) was decreased. Moreover, immunohistochemical analysis (IHC) revealed that the content of α-SMA in liver tissue of BSE-CD treated mice was dramatically decreased. Our findings suggest that BSE-CD treatment attenuates S. japonicum egg-induced hepatic granulomas and fibrosis, at least partly due to reduced NF-κB signaling and the subsequently decreased expression of VEGF, TNF-α, and MCP-1. Suppression of the activation of hepatic stellate cells (HSC) may also be involved in the therapeutic efficacy of BSE-CD.

Impaired lymphocyte profile in schistosomiasis patients with periportal fibrosis

The Th2 immune response in chronic schistosomiasis is associated with the development of periportal fibrosis. However, little is known about the phenotype and activation status of T cells in the process. Objective. To evaluate the profile of T cells in schistosomiasis patients with periportal fibrosis. Methods. It was a cross-sectional study, conducted in the village of Agua Preta, Bahia, Brazil, which included 37 subjects with periportal fibrosis determined by ultrasound. Peripheral blood mononuclear cells were obtained by the Ficcol-hypaque gradient and the frequency of T cells expressing the surface markers CD28, CD69, CD25, and CTLA-4 was determined by flow cytometry. Results. The frequency of CD4⁺CD28⁺ T lymphocytes was higher in individuals with moderate to severe fibrosis compared to patients with incipient fibrosis. We did not observe any significant difference in the frequency of CD4⁺ T cells expressing CD69 among groups of individuals. There was also no significant difference in the frequency of CD8⁺ T cells expressing CD28 or CD69 among the studied groups. Individuals with moderate to severe fibrosis presented a lower frequency of CD8⁺ T cells, CD4⁺CD25^high T cells, and CD4⁺CTLA-4⁺ T cells when compared to patients without fibrosis or incipient fibrosis. The frequency of CD4⁺CD25^low cells did not differ between groups. Conclusion. The high frequency of activated T cells coinciding with a low frequency of putative Treg cells may account for the development of periportal fibrosis in human schistosomiasis.

Cytokine Pattern of T Lymphocytes in Acute Schistosomiasis mansoni Patients following Treated Praziquantel Therapy

Acute schistosomiasis is associated with a primary exposure and is more commonly seen in nonimmune individuals traveling through endemic regions. In this study, we have focused on the cytokine profile of T lymphocytes evaluated in circulating leukocytes of acute Schistosomiasis mansoni-infected patients (ACT group) before and after praziquantel treatment (ACT-TR group). Our data demonstrated increased values of total leukocytes, eosinophils, and monocytes in both groups. Interestingly, we have observed that patients treated with praziquantel showed increased values of lymphocytes as compared with noninfected group (NI) or ACT groups. Furthermore, a decrease of neutrophils in ACT-TR was observed when compared to ACT group. Analyses of short-term in vitro whole blood stimulation demonstrated that, regardless of the presence of soluble Schistosoma mansoni eggs antigen (SEA), increased synthesis of IFN-γ and IL-4 by T-cells was observed in the ACT group. Analyses of cytokine profile in CD8 T cells demonstrated higher percentage of IFN-γ and IL-4 cells in both ACT and ACT-TR groups apart from increased percentage of IL-10 cells only in the ACT group. This study is the first one to point out the relevance of CD8 T lymphocytes in the immune response induced during the acute phase of schistosomiasis.

Efficiency of diagnostic biomarkers among colonic schistosomiasis Egyptian patients

The schistosomal parasite plays a critical role in the development of malignant lesions in different organs. The pathogenesis of cancer is currently under intense investigation to identify reliable prognostic indices for disease detection. The objective of this paper is to evaluate certain biochemical parameters as diagnostic tools to efficiently differentiate between colonic carcinoma and colonic carcinoma associated with schistosomal infection among Egyptian patients. The parameters under investigation are interleukin 2 (IL-2), tumour necrosis factor alpha (TNF-α), carcinoembryonic antigen (CEA) levels, tissue telomerase, pyruvate kinase (PK), glucose-6-phosphate dehydrogenase (G-6-PD) and lactate dehydrogenase (LDH) enzyme activities. The results revealed a significant elevation in the level of the tumour markers IL-2, TNF-α and CEA as well as the activities of LDH, telomerase and G-6-PD among non-bilharzial and bilharzial colonic cancer groups, with a more potent effect in bilharzial infection-associated colonic cancer. A significant inhibition in PK activity was recorded in the same manner as compared to normal tissues. The efficacy of this biomarker was also evaluated through detecting sensitivity, specificity, negative and positive predictive values. In conclusion, schistosomal colonic carcinoma patients displayed more drastic changes in all parameters under investigation. The combination of the selected parameters succeeded in serving as biomarkers to differentiate between the two malignant types.

Chronic hepatosplenomegaly in African school children: a common but neglected morbidity associated with schistosomiasis and malaria

Chronic hepatosplenomegaly, which is known to have a complex aetiology, is common amongst children who reside in rural areas of sub-Saharan Africa. Two of the more common infectious agents of hepatosplenomegaly amongst these children are malarial infections and schistosomiasis. The historical view of hepatosplenomegaly associated with schistosomiasis is that it is caused by gross periportal fibrosis and resulting portal hypertension. The introduction of ultrasound examinations into epidemiology studies, used in tandem with clinical examination, showed a dissociation within endemic communities between presentation with hepatosplenomegaly and ultrasound periportal fibrosis, while immuno-epidemiological studies indicate that rather than the pro-fibrotic Th2 response that is associated with periportal fibrosis, childhood hepatosplenomegaly without ultrasound-detectable fibrosis is associated with a pro-inflammatory response. Correlative analysis has shown that the pro-inflammatory response is also associated with chronic exposure to malarial infections and there is evidence of exacerbation of hepatosplenomegaly when co-exposure to malaria and schistosomiasis occurs. The common presentation with childhood hepatosplenomegaly in rural communities means that it is an important example of a multi-factorial disease and its association with severe and subtle morbidities underlies the need for well-designed public health strategies for tackling common infectious diseases in tandem rather than in isolation.

Pulmonary vascular disease associated with schistosomiasis

In this article we focus on the pathogenesis and clinical characteristics of schistosomiasis infection on the lung vasculature. Overall, the basic biology and understanding of Schistosoma immune responses and their effect on the cardiopulmonary system is limited in both animal and human models, which hinders clinical care and drug development. The inflammatory response to the eggs in the lung appears to contribute to the remodeling of the pulmonary vessels. Portal hypertension caused by parasitemia also appears to contribute to the development of pathophysiologic alterations of the pulmonary vascular bed. Antischistosomal therapy, praziquantel, used for pulmonary hypertension secondary to schistosomiasis usually has no effect, but it is given to prevent further progression of disease. Currently, there are no clinical trials for the treatment of pulmonary vascular disease secondary to schistosomiasis. Specialty drugs such as phosphodiesterase type 5 or tyrosine kinase inhibitors exhibit some interesting activity, yet are prohibitively expensive, lack safety and efficacy studies in schistosomiasis endemic populations, and tend to be limited by safety, efficacy, route of administration and compliance problems.

Seric chemokines and chemokine receptors in eosinophils during acute human schistosomiasis mansoni

The recruitment of circulating eosinophils by chemokines and chemokine receptors plays an important role in the inflammation process in acute human schistosomiasis. Our main focus has been on the plasma chemokines (CXCL8/CCL2/CCL3/CCL24) and chemokine receptors (CCR2/CCR3/CCR5/CXCR1/CXCR2/CXCR3/CXCR4) expressed by circulating eosinophils from acute Schistosoma mansoni infected patients (ACT). Our studies compared ACT patients and healthy individuals as a control group. Our major findings demonstrated a plethora of chemokine secretion with significantly increased secretion of all chemokines analysed in the ACT group. Although no differences were detected for beta-chemokine receptors (CCR2, CCR3 and CCR5) or alpha-chemokine receptors (CXCR3 and CXCR4), a significantly lower frequency of CXCR1+ and CXCR2+ eosinophils in the ACT group was observed. The association between chemokines and their chemokine receptors revealed that acutely infected schistosome patients displaying decreased plasma levels of CCL24 are the same patients who presented enhanced secretion of CCL3, as well as increased expression of both the CCR5 and CXCR3 chemokine receptors. These findings suggest that CCL24 may influence the kinetics of chemokines and their receptors and eosinophils recruitment during human acute schistosomiasis mansoni.

Immunopathogenesis of human schistosomiasis

Schistosomiasis continues to be a significant cause of parasitic morbidity and mortality worldwide. This review considers the basic features of the pathology and clinical outcomes of hepatointestinal and genitourinary schistosomiasis, presents an overview of the numerous studies on animal models that have clarified many of the immunopathological features, and provides insight into our current understanding of the immunopathogenesis and genetic control of human schistosomiasis. In murine schistosomiasis, pathology is induced by a CD4(+) Th2 driven granulomatous response directed against schistosome eggs lodged in the host liver. The Th2 cytokines IL-4 and IL-13 drive this response, whereas IL-10, IL13Ralpha2, IFN-gamma and a subset of regulatory T-cells act to limit schistosome induced pathology. A variety of cell types including hepatic stellate cells, alternatively activated macrophages and regulatory T-cells have also been implicated in the pathogenesis of schistosomiasis. Current knowledge suggests the immunopathogenic mechanisms underlying human schistosomiasis are likely to be similar. The review also considers the future development of anti-pathology schistosome vaccines. As fibrosis is an important feature of many other diseases such as Crohn's disease and sarcoidosis, a comprehensive understanding of the cellular and molecular mechanisms involved in schistosomiasis may also ultimately contribute to the development an effective disease intervention strategy for other granulofibrotic diseases.

Alternative activation of macrophages: an immunologic functional perspective

Macrophages are innate immune cells with well-established roles in the primary response to pathogens, but also in tissue homeostasis, coordination of the adaptive immune response, inflammation, resolution, and repair. These cells recognize danger signals through receptors capable of inducing specialized activation programs. The classically known macrophage activation is induced by IFN-gamma, which triggers a harsh proinflammatory response that is required to kill intracellular pathogens. Macrophages also undergo alternative activation by IL-4 and IL-13, which trigger a different phenotype that is important for the immune response to parasites. Here we review the cellular sources of these cytokines, receptor signaling pathways, and induced markers and gene signatures. We draw attention to discrepancies found between mouse and human models of alternative activation. The evidence for in vivo alternative activation of macrophages is also analyzed, with nematode infection as prototypic disease. Finally, we revisit the concept of macrophage activation in the context of the immune response.