Severe non-atopic asthma: omalizumab can reduce severe asthma exacerbations.

INTRODUCTION: Humanized monoclonal anti-IgE antibody (omalizumab) has demonstrated efficacy in severe atopic asthma. However, few studies have assessed its efficacy in non-atopic and even less in T2-low severe asthma. The objective was to determinate the omalizumab response according to atopic status. METHODS: This retrospective, real-world study was performed in the Chest Diseases Department of Strasbourg University Hospital from January 1, 2006, to June 30, 2017. The response to omalizumab was assessed in 139 patients 4, 6, and 12 months after treatment and compared to data collected prior to omalizumab initiation. RESULTS: Forty-four patients (31.7%) had severe non-atopic asthma and 95 (68.3%) had a severe atopic asthma. In the non-atopic group, omalizumab significantly reduced the severe exacerbation rate by 44% (95% CI 18-64%, p < 0.05), 43% (CI 95% 20-60%, p < 0.05), and 54% (CI 95% 36-67%, p < 0.05), at 4, 6 and 12 months, respectively. A trend toward improvement in FEV1, asthma control and oral corticosteroid use was also observed. These results were not significantly different from those obtained in atopic asthmatics except a more effective oral corticosteroid sparing in atopic group (p < 0.05). Similar reduction of severe exacerbation rates were observed in T2-low asthma subgroup (non-atopic, non-eosinophilic). CONCLUSION: Omalizumab was effective in severe asthma, regardless of atopic status.

Validation of Strasbourg environmental exposure chamber (EEC) ALYATEC® in mite allergic subjects with asthma.

Objective: Environmental Exposure Chamber (EEC) should have standardized and controlled allergenic and non-allergenic exposures to perform reproducible clinical studies. The aim was to demonstrate that mite exposure in the Alyatec® EEC could induce early (EAR) and/or late asthmatic reactions (LAR) in at least 60% of subjects allergic to mite.Methods: The EEC has a volume of 147-m3 with 20 seats. The nebulized particle number, airborne Der p1, endotoxins, and volatile organic compound (VOC) concentrations were measured. Twenty-four asthmatics allergic to mite were randomly exposed to 15, 25, and 46 ng/m3 Der p1. Specificity was assessed in not mite-sensitized asthmatics.Results: No significant endotoxin or VOC contamination was measured. The mean inter-assay CVs were 12.5% for the airborne particle number and 28.7% for airborne Der p1 concentrations. For the three Der p1 concentrations, at least 88% of the subjects developed EAR and/or LAR, and at least 46% developed a dual response. No reaction occurred with placebo or in the control group. No severe bronchial reaction occurred.Conclusions: The Alyatec® EEC demonstrated a tight control of allergenic and non-allergenic exposures. The EEC was clinically validated, with airborne Der p1 levels close to levels found in natural settings.

Cluster analysis of indoor environmental factors associated with symptoms of mite allergy.

BACKGROUND: The clinical efficacy of controlling environmental allergens as a component of allergic asthma treatment remains controversial. Multifaceted allergen reductions appeared to be the most efficient methods. However, they require home visits with indoor technicians. OBJECTIVE: To examine the characteristics of indoor environments that might be related to symptoms of children and adult patients with mite allergic rhinitis and/or asthma. METHODS: We included 315 patients allergic to house dust mites with rhinitis and/or asthma who had been visited at home by 2 medical indoor environment counselors (MIECs) from the Strasbourg University Hospital between January 2007 and June 2015. In a cluster analysis, we analyzed 42 characteristics of respiratory symptoms, dwelling characteristics, and indoor pollutants in this population. RESULTS: Three clusters were defined among the patients. Cluster 1 included 55 patients, all with rhinitis, 32% with asthma, and all living in an urban area. Clusters 2 and 3 included 86 and 174 patients, respectively. The important factors in these 2 clusters were asthma incidence and exposure to different indoor pollutants, such as indoor perfumes, cleaning products, and tobacco smoke. CONCLUSION: Our results underlined the variability of indoor environments and the importance of MIEC home visits to investigate individual patient environments and propose an appropriate avoidance management plan. Our results showed that sensitization to mite and exposure to indoor chemical pollutants were associated with severe asthma.

How In Vitro Assays Contribute to Allergy Diagnosis.

Diagnosis of allergic disorders is based upon the clinical history of the disease, the immunoglobulin E (IgE) antibody response, and the allergen exposure. During the last decade, many changes have occurred in the in vitro diagnostic tests used in daily practice. The most important one is the use of allergenic molecules, which helps to define severe profile of allergy and/or to better understand cross-reactivity. The correlation between IgE sensitization and bronchial or nasal response in provocation tests is not so clear, which implies that such tests are still helpful in allergy diagnosis. In order to strengthen the link between a real allergen exposure and allergic symptoms, environmental allergen load assessment can be performed. For clinicians, it appears obvious to know the pollen count to treat their patients; however, they rarely measure the allergen load in the indoor environment, while nowadays home-tests (semi-quantitative or quantitative) make the assessment very easy. In the future, assessment of the environmental exposure (preferably with an indoor technician) of an allergic patient should take into account not only the allergens but also the other indoor pollutants, which could enhance respiratory symptoms in allergic patients.

Efficacy of bronchial thermoplasty in patients with severe asthma and frequent severe exacerbations: A randomized controlled study✰.

BACKGROUND: Bronchial thermoplasty (BT) is a bronchoscopic procedure for patients with severe uncontrolled asthma, but randomized controlled studies of its efficacy in severe asthma with frequent exacerbations are lacking. The current aim was to assess BT efficacy in this patient population. METHODS: Thirty patients with asthma (GINA 5) who had experienced at least four severe exacerbations in the preceding year were randomized to BT (n = 15) or control groups (n = 15). All patients had four follow-up visits over the following 15 months, corresponding to 3, 6, 9, and 12 months after the last procedure for the BT group. The primary outcome was number of exacerbations at 15 months after inclusion (i.e. 12 months after bronchial thermoplasty). RESULTS: All but three patients had received an asthma biologic without receiving benefit. In the year preceding enrollment, patients in the BT group had an average of five exacerbations, compared with six among controls. For patients in the BT group, oral steroid intake was 9.3 mg/d, compared with 11.0 mg/d among controls. The BT group had 1.58 fewer severe exacerbations (mean, 6.09) compared with controls (mean, 8.28) in the 12-month period after the therapy (p = 0.047). Oral steroid intake during follow-up after BT was significantly lower in the BT group (ratio vs controls: 0.61; p = 0.0002). Quality-of-life measures between inclusion and the last visit were significantly improved in the BT group, but not among controls. Few mild to moderate adverse events were reported, and all were controlled within days. CONCLUSION: In patients with severe asthma and frequent severe exacerbations, BT significantly decreased the rate of severe exacerbations and oral steroid intake and led to improved quality of life during the 15 months after inclusion. BT appears to offer a therapeutic option for severe asthma with frequent exacerbations.

Improvement in severe asthma patients receiving biologics and factors associated with persistent insufficient control: a real-life national study.

BACKGROUND: Biological therapies have revolutionized the treatment of severe asthma with type 2 inflammation. Although such treatments are very effective in reducing exacerbation and the dose of oral steroids, little is known about the persistence of symptoms in severe asthma patients treated with biologics. PURPOSE: We aim to describe asthma control and healthcare consumption of severe asthma patients treated with biologics. DESIGN: The Second Souffle study is a real-life prospective observational study endorsed by the Clinical Research Initiative in Severe Asthma: a Lever for Innovation & Science Network. METHODS: Adults with a confirmed diagnosis of severe asthma for at least 12 months' duration were enrolled in the study. A self-administered questionnaire including the Asthma Control Questionnaire (ACQ), Asthma Quality of Life Questionnaire (AQLQ) and a compliance evaluation test was given to the patients. Healthcare consumption within 12 months prior to enrolment was documented. In patients receiving biologics, doctors indicated whether the patients were biologic responders or non-responders. RESULTS: The characteristics of 431 patients with severe asthma were analysed. Among them, 409 patients (94.9%) presented asthma with type 2 inflammation (T2 high) profile, and 297 (72.6%) patients with a T2 high phenotype were treated with a biologic. Physicians estimated that 88.2% of patients receiving biologics were responders. However, asthma control was only achieved in 25.3% of those patients (ACQ > 0.75). A high proportion of patients (77.8%) identified as responders to biologics were not controlled according to the ACQ score. About 50% of patients continue to use oral corticosteroids either daily (25.2%) or more than three times a year for at least three consecutive days (25.6%). Gastro-oesophageal Reflux Disease (GERD) and Obstructive Sleep Apnoea syndrome (OSA) were identified as independent factors associated with uncontrolled asthma. CONCLUSION: Although a high proportion of severe asthma patients respond to biologics, only 25.3% have controlled asthma. GERD and OSA are independent factors of uncontrolled asthma.

Fast-Onset Diffuse Interstitial Lung Disease in Anti-MDA5 Antibodies-Associated Amyopathic Dermatomyositis.

Anti-MDA5 antibodies-associated amyopathic dermatomyositisis a rare autoimmune disease that involve polyarthritis, cutaneous and pulmonary manifestations. The development of rapidly progressing interstitial lung disease is a life-threatening complication. We report the case of a 45-year-old woman without medical history, who was addressed to the Pulmonary Department for a polyarthritis with dry cough and hypoxemic dyspnea. Initially there was neither cutaneous manifestation nor interstitial lung disease on chest CT scan. After a few days, the patient developed fatal acute respiratory failure with diffuse ground glass opacities. Identification of anti-MDA5 antibodies allowed establishing diagnosis, despite the fact that the first immunological assessment was negative. Corticosteroid bolus of 1 g for three days and immunosuppressive treatment by cyclophosphamide was only initiated at the acute respiratory distress syndrome stage. Given the rapidly unfavorable prognosis of this entity of amyopathic dermatomyositis, the testing for anti-MDA5 antibodies should be recommended in case of progressive pulmonary symptoms associated with joint signs in order to identify this disease at an early stage and to begin rapid and adequate management.

SARS-CoV-2 Pneumonia in Hospitalized Asthmatic Patients Did Not Induce Severe Exacerbation.

BACKGROUND: Viral infections are known to exacerbate asthma in adults. Previous studies have found few patients with asthma among severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia cases. However, the relationship between SARS-CoV-2 infection and severe asthma exacerbation is not known. OBJECTIVE: To assess the frequency of asthma exacerbation in patients with asthma hospitalized for SARS-CoV-2 pneumonia and compare symptoms and laboratory and radiological findings in patients with and without asthma with SARS-CoV-2 pneumonia. METHODS: We included 106 patients between March 4 and April 6, 2020, who were hospitalized in the Chest Diseases Department of Strasbourg University Hospital; 23 had asthma. To assess the patients' asthma status, 3 periods were defined: the last month before the onset of COVID-19 symptoms (p1), prehospitalization (p2), and during hospitalization (p3). Severe asthma exacerbations were defined according to Global INitiative for Asthma guidelines during p1 and p2. During p3, we defined severe asthma deterioration as the onset of breathlessness and wheezing requiring systemic corticosteroids and inhaled ß2 agonist. RESULTS: We found no significant difference between patients with and without asthma in terms of severity (length of stay, maximal oxygen flow needed, noninvasive ventilation requirement, and intensive care unit transfer); 52.2% of the patients with asthma had Global INitiative for Asthma step 1 asthma. One patient had a severe exacerbation during p1, 2 patients during p2, and 5 patients were treated with systemic corticosteroids and inhaled ß2 agonist during p3. CONCLUSIONS: Our results demonstrate that patients with asthma appeared not to be at risk for severe SARS-CoV-2 pneumonia. Moreover, SARS-CoV-2 pneumonia did not induce severe asthma exacerbation.

Mitochondrial Function in Peripheral Blood Mononuclear Cells (PBMC) Is Enhanced, Together with Increased Reactive Oxygen Species, in Severe Asthmatic Patients in Exacerbation.

Asthma is a chronic inflammatory lung syndrome with an increasing prevalence and a rare but significant risk of death. Its pathophysiology is complex, and therefore we investigated at the systemic level a potential implication of oxidative stress and of peripheral blood mononuclear cells' (PBMC) mitochondrial function. Twenty severe asthmatic patients with severe exacerbation (GINA 4-5) and 20 healthy volunteers participated at the study. Mitochondrial respiratory chain complexes activities using different substrates and reactive oxygen species (ROS) production were determined in both groups by high-resolution respirometry and electronic paramagnetic resonance, respectively. Healthy PBMC were also incubated with a pool of plasma of severe asthmatics or healthy controls. Mitochondrial respiratory chain complexes activity (+52.45%, p = 0.015 for VADP) and ROS production (+34.3%, p = 0.02) were increased in asthmatic patients. Increased ROS did not originate mainly from mitochondria. Plasma of severe asthmatics significantly increased healthy PBMC mitochondrial dioxygen consumption (+56.8%, p = 0.031). In conclusion, such asthma endotype, characterized by increased PMBCs mitochondrial oxidative capacity and ROS production likely related to a plasma constituent, may reflect activation of the immune system. Further studies are needed to determine whether increased PBMC mitochondrial respiration might have protective effects, opening thus new therapeutic approaches.

Diversification of the insulin receptor family in the helminth parasite Schistosoma mansoni.

Insulin signalling is a very ancient and well conserved pathway in metazoan cells, dependent on insulin receptors (IR) which are transmembrane proteins with tyrosine kinase activity. A unique IR is usually present in invertebrates whereas two IR members are found with different functions in vertebrates. This work demonstrates the existence of two distinct IR homologs (SmIR-1 and SmIR-2) in the parasite trematode Schistosoma mansoni. These two receptors display differences in several structural motifs essential for signalling and are differentially expressed in parasite tissues, suggesting that they could have distinct functions. The gene organization of SmIR-1 and SmIR-2 is similar to that of the human IR and to that of the IR homolog from Echinococcus multilocularis (EmIR), another parasitic platyhelminth. SmIR-1 and SmIR-2 were shown to interact with human pro-insulin but not with pro-insulin-like growth factor-1 in two-hybrid assays. Phylogenetic results indicated that SmIR-2 and EmIR might be functional orthologs whereas SmIR-1 would have emerged to fulfil specific functions in schistosomes.

Molecular cloning and characterisation of SmSLK, a novel Ste20-like kinase in Schistosoma mansoni.

Serine/threonine kinases of the Ste20 group play important roles in various cellular functions such as growth, apoptosis and morphogenesis. This family includes p21-Activated Kinases (PAKs) and Germinal Center Kinases (GCKs) families which contain their kinase domain in the C-terminal and N-terminal position, respectively. Here, we report the characterisation of a novel Ste20-like kinase (SLK) in the helminth parasite Schistosoma mansoni (SmSLK). SmSLK belongs to the GCK subfamily and contains a conserved N-terminal Ste20-like catalytic domain and C-terminal coiled-coil structures homologous to mammalian Lymphocyte Oriented Kinase (LOK) and SLK kinases and described as regulatory domains in these proteins. Gene assembly was performed using S. mansoni sequences available from genomic databases and indicated that SmSLK is composed of 18 exons and present in one copy in the S. mansoni genome. RT-PCR experiments demonstrated an alternative splicing of SmSLK in the exon 9 encoding the hinge region between kinase and coiled-coil domains of SmSLK and showed the expression of both transcript isoforms (SmSLK and SmSLK-S in which exon 9 is deleted) in all the S. mansoni parasite stages. Most of the Ste20-related proteins are active kinases known to regulate mitogen-activated protein kinase (MAPK) cascades. We demonstrated the kinase activity of SmSLK and SmSLK-S and their capacity to activate the MAPK/Jun N-terminal kinase (JNK) pathway in human embryonic kidney (HEK) cells as well as in Xenopus oocytes. Immunofluorescence studies indicated that SmSLK proteins were abundant in the tegument of adult schistosomes. Therefore, these results indicate that SmSLK is a new member of the GCK protein family that could participate in the regulation of MAPK cascade activation during host-parasite interactions.

Characterization of Schistosoma mansoni Sds homologue, a leucine-rich repeat protein that interacts with protein phosphatase type 1 and interrupts a G2/M cell-cycle checkpoint.

The suppressor of the dis2 mutant (sds22+) has been shown to be an essential regulator in cell division of fission and budding yeast where its deletion causes mitotic arrest. Its role seems to take place through the activation of PP1 (protein phosphatase type 1) in Schizosaccharomyces pombe. In the trematode Schistosoma mansoni, we have identified the Sds22 homologue (SmSds), and the PP1 (SmPP1). We showed by using a GST (glutathione S-transferase) pull-down assay that the SmSds gene product interacts with SmPP1 and that the SmSds-SmPP1 complex is present in parasite extracts. Furthermore, we observed that SmSds inhibited PP1 activity. Functional studies showed that the microinjection of SmSds into Xenopus oocytes interacted with the Xenopus PP1 and disrupted the G2/M cell-cycle checkpoint by promoting progression to GVBD (germinal vesicle breakdown). Similar results showing the appearance of GVBD were observed when oocytes were treated with anti-PP1 antibodies. Taken together, these observations suggest that SmSds can regulate the cell cycle by binding to PP1.

Growth factor receptors in helminth parasites: signalling and host-parasite relationships.

Parasitic helminths remain major pathogens of both humans and animals throughout the world. The success of helminth infections depends on the capacity of the parasite to counteract host immune responses but also to exploit host-derived signal molecules for its development. Recent progress has been made in the characterization of growth factor receptors of various nematode and flatworm parasites with the demonstration that transforming growth factor beta (TGF-beta), epidermal growth factor (EGF) and insulin receptor signalling pathways are conserved in helminth parasites and potentially implicated in the host-parasite molecular dialogue and parasite development.

Glyceroneogenesis: an unexpected metabolic pathway for glutamine in Schistosoma mansoni sporocysts.

To date, glyceroneogenesis has only been described in mammals but we demonstrate in this paper that it could exist in the invertebrate Schistosoma mansoni, the parasitic helminth transmitted by fresh water molluscs and responsible for the major human endemic disease, schistosomiasis. Glyceroneogenesis is a phosphoenolpyruvate carboxykinase (PEPCK)-dependent process by which glycerol can be produced from precursors like glutamine and therefore represents a truncated gluconeogenic pathway. We have previously demonstrated the possible central role of glutamine in mollusc-schistosome interactions. In this work, we show that glutamine effectively promotes in vitro survival and protein synthesis in sporocysts, the intramolluscan larval stages of S. mansoni, possibly through its role as an energy source. However, the demonstration that PEPCK is massively expressed in these larval forms as compared to adult parasites, together with the observation that 3-mercaptopicolinate, a specific inhibitor of PEPCK, significantly reduces the effect of glutamine on sporocyst growth, suggest that glutamine could also be used for glucose or glycerol production. Results of [14C] glutamine incorporation confirmed that neosynthesis of glucose and mainly of glycerol occurred in sporocysts and was dependent on PEPCK activity. Therefore, our results strongly indicate that glyceroneogenesis could exist in schistosomes. Several hypotheses can be proposed concerning the importance of glycerol for the adaptation of this helminth to its host osmotic and energetic environment.

A new family of receptor tyrosine kinases with a venus flytrap binding domain in insects and other invertebrates activated by aminoacids.

BACKGROUND: Tyrosine kinase receptors (RTKs) comprise a large family of membrane receptors that regulate various cellular processes in cell biology of diverse organisms. We previously described an atypical RTK in the platyhelminth parasite Schistosoma mansoni, composed of an extracellular Venus flytrap module (VFT) linked through a single transmembrane domain to an intracellular tyrosine kinase domain similar to that of the insulin receptor. METHODS AND FINDINGS: Here we show that this receptor is a member of a new family of RTKs found in invertebrates, and particularly in insects. Sixteen new members of this family, named Venus Kinase Receptor (VKR), were identified in many insects. Structural and phylogenetic studies performed on VFT and TK domains showed that VKR sequences formed monophyletic groups, the VFT group being close to that of GABA(B) receptors and the TK one being close to that of insulin receptors. We show that a recombinant VKR is able to autophosphorylate on tyrosine residues, and report that it can be activated by L-arginine. This is in agreement with the high degree of conservation of the alpha amino acid binding residues found in many amino acid binding VFTs. The presence of high levels of vkr transcripts in larval forms and in female gonads indicates a putative function of VKR in reproduction and/or development. CONCLUSION: The identification of RTKs specific for parasites and insect vectors raises new perspectives for the control of human parasitic and infectious diseases.

Protein tyrosine kinases as new potential targets against human schistosomiasis.

In spite of the numerous efforts made to control their transmission, parasite schistosomes still represent a serious public health concern and a major economic problem in many developing countries. Praziquantel (PZQ) is the drug of choice for the treatment of schistosomiasis and the only one that is available for mass chemotherapy. However, its widespread use and its inefficacy on juvenile parasites raise fears that schistosomes will develop drug resistance, and make the development of alternative drugs highly desirable. Protein tyrosine kinases (PTKs) are key molecules that control cell differentiation and proliferation and they already represent important targets for molecular cancer therapy. The recent characterization in Schistosoma mansoni of several cytosolic and receptor PTKs, with properties similar but also divergent from their vertebrate counterparts, opens new perspectives for the development of novel strategies in chemotherapy of schistosomiasis, which could be based on the use of parasite-specific tyrosine phosphorylation inhibitors.

SmPKC1, a new protein kinase C identified in the platyhelminth parasite Schistosoma mansoni.

Schistosoma mansoni signal transduction pathways are promising sources of target molecules for the development of novel control strategies against this platyhelminth parasite of humans. Members of the protein kinase C (PKC) family play key roles in such pathways activated by both receptor tyrosine kinases and other receptors, controlling a variety of physiological processes. Here, we report the cloning and molecular characterization of the first PKC identified in S. mansoni. Structural analysis indicated that SmPKC1 exhibits all the features typical of the conventional PKC subfamily. The gene structure was determined in silico and found to comprise a total of 15 exons and 14 introns. This structure is highly conserved; all intron positions are also present in the human PKCbeta gene and most of the exon sizes are identical. Using PCR on genomic DNA we were able to show that putative orthologues of SmPKC1 are present in 9 Schistosoma species. SmPKC1 expression is developmentally regulated with the highest level of transcripts in miracidia, whereas SmPKC1 protein expression is higher in the sporocyst. The localization of SmPKC1 on the sporocyst ridge cyton and in schistosomula acetabular glands suggests that the enzyme plays a role in signal transduction pathways associated with larval transformation.

Schistosoma mansoni: ferredoxin-NADP(H) oxidoreductase and the metabolism of reactive oxygen species.

Mitochondrial-type ferredoxin-NADP(H) oxidoreductases (FNR) catalyze the electron transport between NADPH and substrates such as ferredoxins. Even though enzymes belonging to this family are present in several organisms, including prokaryotes, their biological function is not clearly understood. In a previous work, we reported the existence of a mitochondrial-type FNR in the trematode Schistosoma mansoni (SmFNR). This enzyme conferred tolerance to oxidative stress conditions when tested in an heterologous system. In this work, we demonstrate that the SmFNR can be imported to mitochondria in mammal cells and show that its expression is induced in parasite cultures by reactive oxygen species (ROS). The results reported herein give further support to the involvement of SmFNR in ROS metabolism.