Notch dimerization and gene dosage are important for normal heart development, intestinal stem cell maintenance, and splenic marginal zone B-cell homeostasis during mite infestation.

Cooperative DNA binding is a key feature of transcriptional regulation. Here we examined the role of cooperativity in Notch signaling by CRISPR-mediated engineering of mice in which neither Notch1 nor Notch2 can homo- or heterodimerize, essential for cooperative binding to sequence-paired sites (SPS) located near many Notch-regulated genes. Although most known Notch-dependent phenotypes were unaffected in Notch1/2 dimer-deficient mice, a subset of tissues proved highly sensitive to loss of cooperativity. These phenotypes include heart development, compromised viability in combination with low gene dose, and the gut, developing ulcerative colitis in response to 1% dextran sulfate sodium (DSS). The most striking phenotypes-gender imbalance and splenic marginal zone B-cell lymphoma-emerged in combination with gene dose reduction or when challenged by chronic fur mite infestation. This study highlights the role of the environment in malignancy and colitis and is consistent with Notch-dependent anti-parasite immune responses being compromised in Notch dimer-deficient animals.

A man in his 80s with arthritis and persistent fever. / En mann i 80-årene med leddgikt og vedvarende feber.

BACKGROUND: Febrile illness is a common clinical problem and frequently caused by bacterial and viral infections. When blood cultures are negative and symptoms persist despite empirical antibiotic treatment, clinicians must consider other differential diagnoses including malignancy, rheumatologic disease and parasitic infections. CASE PRESENTATION: A Norwegian male in his eighties experienced febrile illness during a stay in Southern Spain. Upon return to Norway, he was hospitalized with fever, weight-loss, enlarged spleen, pancytopenia and hypergammaglobulinemia. After failing to respond to broad-spectrum antibiotics and antifungals, he was diagnosed with visceral leishmaniasis and Leishmania infantum was confirmed by PCR and sequencing of spleen biopsy and blood. INTERPRETATION: With increasing migration and tourism, doctors in non-endemic countries should be familiar with visceral leishmaniasis.

Case Report: Hyperreactive Malarial Splenomegaly Syndrome Diagnosed with Loop-Mediated Isothermal Amplification and Treated with Artemisinin-Based Combination Therapy.

Hyperreactive malarial splenomegaly syndrome (HMSS) is a rare cause of splenomegaly in the Western world. Hyperreactive malarial splenomegaly syndrome is caused by an aberrant immunological response to chronic malaria exposure in endemic areas. Revised Fakunle's criteria may be helpful for diagnosis: persistent splenomegaly (> 10 cm below the costal margin), increased anti-Plasmodium antibodies, increased IgM levels, exclusion of other causes of splenomegaly or malignancy, and a favorable response to antimalarial treatment. We describe the case of a 16-year-old patient, who recently arrived in Belgium from Guinea with a history of splenomegaly and B symptoms in whom HMSS diagnosis was achieved, thanks to the loop-mediated isothermal amplification method. To our knowledge, this is also the first described case treated by dihydroartemisinin/piperaquine.

Correlation between the values of circulating blood elements with the size of spleen in the presence of schistosomal splenomegaly

Abstract Purpose: To evaluate a possible relationship between the size of the spleen and values of circulating blood elements in patients with schistosomatic splenomegaly. Methods: ixty one patients with hepatosplenic schistosomiasis mansoni underwent a clinical exam and peripheral venous blood was collected for a hemogram. The erythrocyte, hemoglobin, hematocrit, leukocyte, and platelet values were determined. All patients underwent abdominal ultrasound to measure the spleen. The hematological test results were compared to the size of the spleen. Results: The size of the spleen varied from 14.0 to 28.4 (19.9 ± 3.7) cm according to the ultrasound image. Thrombocytopenia was observed 58 (95%) patients, leukopenia in 55 (90%) patients, and anemia in 32 (52.4%) patients. Leukopenia was proportional to splenomegaly. Conclusion: Schistosomal splenomegaly leads to leukopenia in direct proportion to the size of the spleen.

Co-infection: the outcome of Plasmodium infection differs according to the time of pre-existing helminth infection.

Although helminth-Plasmodium coinfections are common in tropical regions, the implications of this co-existence for the host immune response are poorly understood. In order to understand the effect of helminth infection at different times of coinfection on the immune response against Plasmodium infection, BALB/c mice were intraperitoneally infected with Taenia crassiceps (Tc). At 2 (Tc2) or 8 (Tc8) weeks post-infection, mice were intravenously infected with 1 × 103 Plasmodium yoelii (Py) 17XL-parasitized red blood cells. Py 17XL-single-infected mice developed cachexia, splenomegaly, and anemia, and died at 11 days post-infection. Importantly, Tc2 + Py-coinfected mice showed increased survival of 58% on day 11, but developed pathology (cachexia and splenomegaly) and succumbed on day 18 post-coinfection, this latter associated with high levels of IL-1ß and IL-12, and reduced IFN-γ in serum compared with Py 17XL-single-infected mice. Interestingly, Tc8 + Py-coinfected mice showed increased survival up to 80% on day 11 and succumbed on day 30 post-coinfection. This increased survival rate conferred by chronic helminth infection was associated with a decreased pathology and mixed inflammatory-type 1/anti-inflammatory-type 2 immune profile as evidenced by the production of high levels of IL-12 and IL-10, and reduced TNF-α from macrophages, high levels of IL-4 and IL-10, and low levels of IFN-γ from spleen cells. Also high serum levels of IL-1ß, TNF-α, IL-12, IL-4, and IL-10, but a significant reduction of IFN-γ were observed. Together, these data indicate that polarization of the cell-mediated response modulated by a pre-existing helminth infection differentially impacts on the host immune response to Py 17XL in a time-dependent manner.

Hepatic schistosomiasis with massive splenomegaly: a case report and literature review.

Schistosomiasis is a parasitic disease caused by Schistosoma species. Intestinal and hepatic schistosomiases are the most common forms of chronic disease. We describe a case of a 26-year old patient from Eritrea who was referred to our hospital with abdominal pain and diarrhea. The diagnosis of hepatosplenic schistosomiasis was made by liver biopsy and the patient was treated with praziquantel. Hepatic schistosomiasis is characterised by deposition of schistosomal eggs in the liver which results in a host cell immune response and leads to granuloma formation and neoangiogenesis. This is hallmarked by different grades of periportal fibrosis with portal hypertension leading to splenomegaly. Normal liver architecture is preserved and periportal fibrosis can be reversible if treated adequately and timely. With a recent native schistosomiasis cluster report from France and the expected influx to Europe of persons from regions endemic for schistosomiasis, increased awareness of this disease in healthcare practitioners is needed. We review the epidemiology, pathogenesis, clinical presentation and treatment of schistosomiasis.

The Schistosomiasis SpleenOME: Unveiling the Proteomic Landscape of Splenomegaly Using Label-Free Mass Spectrometry.

Schistosomiasis is a neglected parasitic disease that affects millions of people worldwide and is caused by helminth parasites from the genus Schistosoma. When caused by S. mansoni, it is associated with the development of a hepatosplenic disease caused by an intense immune response to the important antigenic contribution of adult worms and to the presence of eggs trapped in liver tissue. Although the importance of the spleen for the establishment of immune pathology is widely accepted, it has received little attention in terms of the molecular mechanisms operating in response to the infection. Here, we interrogated the spleen proteome using a label-free shotgun approach for the potential discovery of molecular mechanisms associated to the peak of the acute phase of inflammation and the development of splenomegaly in the murine model. Over fifteen hundred proteins were identified in both infected and control individuals and 325 of those proteins were differentially expressed. Two hundred and forty-two proteins were found upregulated in infected individuals while 83 were downregulated. Functional enrichment analyses for differentially expressed proteins showed that most of them were categorized within pathways of innate and adaptive immunity, DNA replication, vesicle transport and catabolic metabolism. There was an important contribution of granulocyte proteins and antigen processing and presentation pathways were augmented, with the increased expression of MHC class II molecules but the negative regulation of cysteine and serine proteases. Several proteins related to RNA processing were upregulated, including splicing factors. We also found indications of metabolic reprogramming in spleen cells with downregulation of proteins related to mitochondrial metabolism. Ex-vivo imunophenotyping of spleen cells allowed us to attribute the higher abundance of MHC II detected by mass spectrometry to increased number of macrophages (F4/80+/MHC II+ cells) in the infected condition. We believe these findings add novel insights for the understanding of the immune mechanisms associated with the establishment of schistosomiasis and the processes of immune modulation implied in the host-parasite interactions.

Praziquantel Targets M1 Macrophages and Ameliorates Splenomegaly in Chronic Schistosomiasis.

Splenomegaly is a common feature of many infectious diseases, including schistosomiasis japonica. However, the immunopathogenesis and the treatment of splenomegaly due to schistosomiasis have been largely neglected. Praziquantel (PZQ), a classical schistosomicide, has been demonstrated by us and others to have antifibrotic and anti-inflammatory activities against schistosomiasis. In this study, we investigated the effect of PZQ on alleviating the splenomegaly caused by Schistosoma japonicum infection in mice. The results showed that the number of macrophages, especially the number of M1 macrophages, was significantly increased in the enlarged spleens of infected mice (P < 0.001). After PZQ treatment for 4 weeks, the number of splenic macrophages, especially the number of M1 macrophages, was significantly reduced (P < 0.001) by the way of apoptosis, and another schistosomicide, mefloquine, had no effect either on the splenomegaly or on reducing the number of macrophages. Furthermore, by using the murine macrophage line RAW 264.7, we found that PZQ could inhibit the formation of the NLRP3 inflammasome and attenuate phagocytic activity in M1 macrophages. Thus, our studies suggest that PZQ plays a powerful role in ameliorating the splenomegaly caused by S. japonicum infection, which presents a new strategy for the therapy of splenomegaly resulting from other pathological conditions.

Disease severity in patients with visceral leishmaniasis is not altered by co-infection with intestinal parasites.

Visceral leishmaniasis (VL) is a neglected tropical disease that affects the poorest communities and can cause substantial morbidity and mortality. Visceral leishmaniasis is characterized by the presence of Leishmania parasites in the spleen, liver and bone marrow, hepatosplenomegaly, pancytopenia, prolonged fever, systemic inflammation and low body mass index (BMI). The factors impacting on the severity of VL are poorly characterized. Here we performed a cross-sectional study to assess whether co-infection of VL patients with intestinal parasites influences disease severity, assessed with clinical and haematological data, inflammation, cytokine profiles and BMI. Data from VL patients was similar to VL patients co-infected with intestinal parasites, suggesting that co-infection of VL patients with intestinal parasites does not alter disease severity.

B-cell activating factor deficiency suppresses splenomegaly during Leishmania donovani infection.

B-cell activating factor (BAFF) is a critical regulator for B-cell development and differentiation. We previously reported elevation of serum BAFF levels in patients with visceral leishmaniasis (VL). In this study, we examined if BAFF is involved in pathologies during infection of Leishmania donovani. BALB/cA mice infected with L. donovani showed significant elevation in serum BAFF and IgG levels as seen in VL patients. In contrast, elevation of serum IgG by L. donovani infection was significantly suppressed in BAFF-deficient mice. The spleen weight of the BAFF-deficient mice after infection was significantly lower than that of the infected wild-type mice, whereas comparable degree of hepatomegaly and anemia were observed in those mice. In the enlarged spleen of L. donovani-infected wild-type mice, increase of CD19+ lymphocytes was more prominent than that of CD3+ cells, suggesting the contribution of B cell increase to splenomegaly during VL. Besides, increase of CD19+ lymphocytes was not found in BAFF-deficient mice after L. donovani infection. Taken together, these results suggest that BAFF is involved in strong B cell activation, which has a pathological role in splenomegaly but not in hepatomegaly or anemia, during VL.

[Splenomegaly in an Eritrean refugee: the hyper-reactive malaria splenomegaly syndrome.] / Splenomegalie bij een Eritrese vluchteling.

BACKGROUND: Hyper-reactive malaria splenomegaly (HMS) is a rare and potentially severe complication of malaria. It is likely that the incidence of patients with HMS will rise in the Netherlands due to the recent increase in asylum-seekers from Sub-Saharan Africa. It can be difficult to diagnose this disease, as this case shows. CASE DESCRIPTION: A 31-year-old male from Eritrea was admitted with fever and dyspnea, caused by an influenza A-infection. The patient also presented with cachexia, pronounced hepatosplenomegaly and pancytopenia. Microscopic diagnostic analysis for malaria was negative. HMS was eventually diagnosed through high-sensitivity qPCR for malaria, which showed the presence of a very low level of Plasmodium falciparum parasitemia; furthermore, IgM levels were high and malaria serology was strongly positive. CONCLUSION: HMS should be considered in patients from malaria-endemic areas presenting with splenomegaly and pancytopenia. Because standard diagnostics for malaria are often negative in this population, malaria serology and sensitive qPCR play an important diagnostic role.

[Visceral leishmaniasis in adults: about twelve cases]. / La leishmaniose viscérale chez l'adulte à propos de douze cas.

Visceral leishmaniasis is a vector-borne disease essentially associated with Leishmania infantum infection in the Mediterranean basin. Although rare in adults, its prevalence has recently increased even among immunocompetent individuals. The aim of our study is to reveal the epidemiological features of visceral leishmaniasis in adults and the importance of biological diagnostic in the identification of this disease. Our study spanned six years from January 2009 to January 2014 and data were collected from twelve patients hospitalized at University Hospital Hassan II, Fez. Alteration of general state and splenomegaly dominated the clinical picture. Biologically, anemia was almost constant. Diagnosis was confirmed by parasite identification at the level of bone marrow. The response to treatment was favorable for all our patients. Thus, visceral leishmaniasis recrudescence in adults and its nonspecific clinical picture must lead the clinicians to suspect it when fever accompanying splenomegaly occurs, thus enabling early diagnosis and therapeutic management.

The formation of egg granulomas in the spleens of mice with late Schistosoma japonicum infection alters splenic morphology.

BACKGROUND: Splenomegaly is a characteristic symptom of schistosome infection. Unlike the well known hepatic pathology of schistosomiasis, splenomegaly has received little scientific research and is generally considered to be a non-specific congestion caused by increased blood pressure within the venous sinuses. Moreover, to date, few studies have reported the deposition of schistosome eggs in the spleen. In a previous study, however, we observed that prolonged S. japonicum infections destroyed the structure of the lymphoid follicles in the spleen of mice at 8 weeks post-infection and found that eggs were frequently deposited in the spleen. These prior observations suggested a relationship between granulomas and splenic morphology which we investigate further in this study. METHODS: C57BL/6 mice were infected percutaneously with twenty cercariae of S. japonicum and sacrificed at different times post-infection. The number of eggs present in the homogenates of spleens and livers was quantified by light microscopy. Splenic pathology was observed by immunohistochemistry staining of paraffin-embedded sections. At 18 weeks post-infection the infected mice were divided into two groups (granulomatous spleens and non-granulomatous spleens). Serum antibodies and cytokines in the antigen- or mitogen-stimulated lymphocyte cultures were then determined by ELISA. RESULTS: We found that eggs deposition in the spleens of infected mice occurred frequently but only occasionally led to granulomas formation. The lymphoid follicles within the granulomatous spleens maintained their structural integrity until 20 weeks post-infection, unlike the lymphoid follicles in spleens without egg granulomas. Mice with granulomatous spleens accompanied by lymphoid follicles exhibited a germinal center (GC)-like structure and had enhanced humoral immune responses. Splenocytes from granulomatous spleens also showed significantly elevated levels of Th2 cytokines during late infection stages. CONCLUSIONS: Our results highlight that lymphoid follicles, which are not completely destroyed or are re-established in the spleen, can change the local immune environment and lead to changes in the splenic morphology of mice with chronic schistosomiasis.

The neurotrophic receptor Ntrk2 directs lymphoid tissue neovascularization during Leishmania donovani infection.

The neurotrophic tyrosine kinase receptor type 2 (Ntrk2, also known as TrkB) and its ligands brain derived neurotrophic factor (Bdnf), neurotrophin-4 (NT-4/5), and neurotrophin-3 (NT-3) are known primarily for their multiple effects on neuronal differentiation and survival. Here, we provide evidence that Ntrk2 plays a role in the pathologic remodeling of the spleen that accompanies chronic infection. We show that in Leishmania donovani-infected mice, Ntrk2 is aberrantly expressed on splenic endothelial cells and that new maturing blood vessels within the white pulp are intimately associated with F4/80(hi)CD11b(lo)CD11c(+) macrophages that express Bdnf and NT-4/5 and have pro-angiogenic potential in vitro. Furthermore, administration of the small molecule Ntrk2 antagonist ANA-12 to infected mice significantly inhibited white pulp neovascularization but had no effect on red pulp vascular remodeling. We believe this to be the first evidence of the Ntrk2/neurotrophin pathway driving pathogen-induced vascular remodeling in lymphoid tissue. These studies highlight the therapeutic potential of modulating this pathway to inhibit pathological angiogenesis.

Clinical management of advanced schistosomiasis: a case of portal vein thrombosis-induced splenomegaly requiring surgery.

We report for the first time in the Philippines a case of portal vein thrombosis in a 12 year old Filipino boy with advanced schistosomiasis. The boy was referred to the Research Institute for Tropical Medicine (RITM), Manila, due to a rapidly enlarging spleen post-praziquantel treatment. At RITM, liver function tests were within normal limits but complete blood examinations showed pancytopenia and abnormal coagulation times. Serum markers for hepatitis A, B and C were negative. Abdominal MRI revealed schistosome-induced periportal fibrosis. The main portal vein appeared thrombosed with characteristic cavernous transformation of the right portal vein. Varices were seen in the oesophagus, gastrohepatic ligament, and splenic hilum. The spleen was markedly enlarged, with parenchymal foci representing Gamna-Gandy bodies. The patient underwent splenectomy. Histopathologic findings in the liver showed moderate pipestem fibrosis and schistosome egg granulomas. The patient was discharged from the hospital in excellent clinical condition.

Co-infection restrains Litomosoides sigmodontis filarial load and plasmodial P. yoelii but not P. chabaudi parasitaemia in mice.

Infection with multiple parasite species is clearly the norm rather than the exception, in animals as well as in humans. Filarial nematodes and Plasmodium spp. are important parasites in human public health and they are often co-endemic. Interactions between these parasites are complex. The mechanisms underlying the modulation of both the course of malaria and the outcome of filarial infection are poorly understood. Despite increasing activity in recent years, studies comparing co- and mono-infections are very much in their infancy and results are contradictory at first sight. In this study we performed controlled and simultaneous co-infections of BALB/c mice with Litomosoides sigmodontis filaria and with Plasmodium spp. (Plasmodium yoelii 17 XNL or Plasmodium chabaudi 864VD). An analysis of pathological lesions in the kidneys and lungs and a parasitological study were conducted at different times of infection. Whatever the plasmodial species, the filarial recovery rate was strongly decreased. The peak of parasitaemia in the plasmodial infection was decreased in the course of P. yoelii infection but not in that of P. chabaudi. Regarding pathological lesions, L. sigmodontis can reverse lesions in the kidneys due to the presence of both Plasmodium species but does not modify the course of pulmonary lesions. The filarial infection induces granulomas in the lungs.

Leishmaniasis--an unusual cause of splenomegaly in Romania.

Leishmaniasis is a parasitic infection caused by protozoans classified as Leishmania species. Romania is not considered an endemic country and there are only few reports of sporadic cases in the last 100 years. However, studies suggest that the disease is spreading north. We present the case of a 44 year old female that presented with asthenia, perspirations, vertigo, weight loss and menometrorhagias in small to medium quantity. Clinical exam revealed the presence of splenomegaly and her blood tests indicated she had pancitopenia; differential diagnosis included myeloproliferative or lymphoproliferative disorders, infections that evolve with spleen enlargement, autoimmune-related splenomegaly and hepatic--all tests were negative. She refused the bone marrow aspiration. Three months later, her condition worsened and the menometrorragias became more severe. Bone marrow aspiration revealed the presence of numerous intra and extracellular Leishmania spp. amastigotes. A detailed anamnesis showed that she had worked for six months in Italy as a care-giver nine months ago. She was transferred to Bucharest where she received optimal treatment. However, due to the continuous bleeding, the evolution was unfavourable. This is an alarm sign for physicians that should take into account the fact that, due to population migration and global warming, tropical infectious diseases are becoming more and more common. The signs and symptoms, as well as the treatment in leishmaniasis are reviewed, as well as a brief history of leishmaniasis in Romania.

Isolation, cloning, and pathologic analysis of Trypanosoma evansi field isolates.

In recent years, the emergence of highly pathogenic Trypanosoma evansi strains in the Philippines has resulted in substantial losses in livestock production. In this study, we isolated T. evansi from infected-water buffaloes in the Philippines and analyzed their virulence using mice and cattle. A total of 10 strains of T. evansi were isolated. Evaluation of the virulence of each strain using mice depicted significant differences among the strains in the prepatent period, the level of parasitemia, and the survival time of the infected animals. In mice infected with the highly pathogenic T. evansi, signs of excessive inflammation such as marked splenomegaly and increase more than 6-fold in the number of leukocytes were observed at 8 days post-infection. To study the virulence of the parasite strains in cattle (which are the common T. evansi hosts in Philippines), cattle were infected with the T. evansi isolates that showed high and low virulence in mice. The rate of parasite growth and the length of the prepatent periods were found to be similar to those observed in mice for the respective strains. The cattle infected with the highly pathogenic strain developed anemia and a marked decrease in leukocyte counts. To determine the cause of the pathological changes, we analyzed the expression levels of inflammatory cytokines and observed up-regulation of tumor necrosis factor-α in anemic infected cattle. Our findings suggest that the epidemic of T. evansi in the Philippines is characterized by T. evansi strains with varying virulences from low to very high pathogenicity in cattle.