FIBCD1 Deficiency Decreases Disease Severity in a Murine Model of Invasive Pulmonary Aspergillosis.

Aspergillus fumigatus is a ubiquitous mold associated with the development of pulmonary diseases that include invasive pulmonary aspergillosis (IPA), an often fatal opportunistic infection. FIBCD1 is a transmembrane endocytic membrane receptor widely expressed on human epithelium. Although FIBCD1 was previously shown to bind chitin, modulate fungal colonization of the gut, and inhibit intestinal inflammation, the role of FIBCD1 in the context of lung fungal infection remains unknown. In this study, we observed that mortality, fungal burden, and tissue histopathology were decreased in the absence of FIBCD1 in murine IPA. Quantitative RT-PCR analyses demonstrated decreased inflammatory cytokines in the lungs of neutrophil-depleted FIBCD1-/- mice with IPA, when compared with wild-type controls. In contrast, inflammatory cytokines were increased in immune-competent FIBCD1-/- mice after fungal aspiration, suggesting that the presence of neutrophils is associated with cytokine modulation. In contrast to the clear IPA phenotype, FIBCD1-/- mice with systemic infection or bleomycin-induced lung injury exhibited similar morbidity and mortality when compared with their wild-type counterparts. Thus, our study identifies a detrimental role of FIBCD1 in IPA.

Vaccine-Induced Protection in Two Murine Models of Invasive Pulmonary Aspergillosis.

Life-threatening, invasive fungal infections (IFIs) cause over 1.5 million deaths worldwide and are a major public health concern with high mortality rates even with medical treatment. Infections with the opportunistic fungal pathogen, Aspergillus fumigatus are among the most common. Despite the growing clinical need, there are no licensed vaccines for IFIs. Here we evaluated the immunogenicity and protective efficacy of an A. fumigatus recombinant protein vaccine candidate, AF.KEX1, in experimental murine models of drug-induced immunosuppression. Immunization of healthy mice with AF.KEX1 and adjuvant induced a robust immune response. Following AF.KEX1 or sham immunization, mice were immunosuppressed by treatment with either cortisone acetate or hydrocortisone and the calcineurin inhibitor, tacrolimus. To test vaccine efficacy, immunosuppressed mice were intranasally challenged with A. fumigatus conidia (Af293) and weight and body temperature were monitored for 10 days. At study termination, organism burden in the lungs was evaluated by quantitative PCR and Gomori's methanamine silver staining. In both models of immunosuppression, AF.KEX1 vaccinated mice experienced decreased rates of mortality and significantly lower lung organism burden compared to non-vaccinated controls. The lung fungal burden was inversely correlated with the peak anti-AF.KEX1 IgG titer achieved following vaccination. These studies provide the basis for further evaluation of a novel vaccine strategy to protect individuals at risk of invasive aspergillosis due to immunosuppressive treatments.

Serum amyloid P component is an essential element of resistance against Aspergillus fumigatus.

Serum amyloid P component (SAP, also known as Pentraxin 2; APCS gene) is a component of the humoral arm of innate immunity involved in resistance to bacterial infection and regulation of tissue remodeling. Here we investigate the role of SAP in antifungal resistance. Apcs-/- mice show enhanced susceptibility to A. fumigatus infection. Murine and human SAP bound conidia, activate the complement cascade and enhance phagocytosis by neutrophils. Apcs-/- mice are defective in vivo in terms of recruitment of neutrophils and phagocytosis in the lungs. Opsonic activity of SAP is dependent on the classical pathway of complement activation. In immunosuppressed mice, SAP administration protects hosts against A. fumigatus infection and death. In the context of a study of hematopoietic stem-cell transplantation, genetic variation in the human APCS gene is associated with susceptibility to invasive pulmonary aspergillosis. Thus, SAP is a fluid phase pattern recognition molecule essential for resistance against A. fumigatus.

Early-Warning Immune Predictors for Invasive Pulmonary Aspergillosis in Severe Patients With Severe Fever With Thrombocytopenia Syndrome.

Aspergillus-related disease was confirmed to be associated with immune disorders in patients, severe patients with severe fever with thrombocytopenia syndrome (SFTS) infected by novel phlebovirus were confirmed to have severe immune damage including cellular immunosuppression and cytokine storms. Secondary invasive pulmonary aspergillosis (IPA) in severe SFTS patients can increase fatality rate. This study investigated early-warning predictive factors of secondary IPA in severe SFTS patients. Receiver operating characteristic analysis was used to assess the value of immune parameters to predict IPA in SFTS patients. The cut-off values of CD4+ and CD8+ T-cell counts to predict IPA were 68 and 111 cells/mm3, with sensitivities of 82.6% and 72%, and specificities of 56.7% and 83.3%, respectively. Cut-off values of IL-6, TNF-α, IL-8, and IL-10 to predict IPA incidence in critically ill SFTS patients were 99 pg/mL, 63 pg/mL, 120 pg/mL, and 111 pg/mL, with sensitivities of 90.0%, 86.7%, 83.3% and 90.0% and specificities of 80.4%, 71.7%, 82.6% and 65.2%, respectively. Lower CD4+ and CD8+ T-cells counts, higher levels of IL-6, TNF-α, IL-8 and IL-10, higher incidence of pancreatic and renal damage, early antibacterial therapy of carbapenems, and intensive care unit admission were risk factors of IPA in SFTS patients. Multivariate logistic regression analysis indicated counts of CD4+ T-cells <68 cells/mm3 combined with CD8+ T-cells <111 cells/mm3 (odds ratio [OR] 0.218, 95% confidence interval [CI] 0.059-0.803, p=0.022), IL-6 >99 pg/ml combined with IL-10 >111 pg/ml (OR 17.614, 95% CI 2.319-133.769, p=0.006), and brain natriuretic peptide level >500 pg/ml (OR 13.681, 95% CI 1.994-93.871, p=0.008) were independent risk factors for IPA in SFTS patients. The mortality in the IPA group was significantly higher than in the non-IPA group (p=0.001). Early antifungal treatment of IPA patients was significantly associated with improved survival (log-rank, p=0.022). Early diagnosis of IPA and antifungal treatment can improve the prognosis of SFTS patients. Besides, we speculate SFTS may be as a host factor for IPA.

Genetic Variation in PFKFB3 Impairs Antifungal Immunometabolic Responses and Predisposes to Invasive Pulmonary Aspergillosis.

Activation of immune cells in response to fungal infection involves the reprogramming of their cellular metabolism to support antimicrobial effector functions. Although metabolic pathways such as glycolysis are known to represent critical regulatory nodes in antifungal immunity, it remains undetermined whether these are differentially regulated at the interindividual level. In this study, we identify a key role for 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) in the immunometabolic responses to Aspergillus fumigatus. A genetic association study performed in 439 recipients of allogeneic hematopoietic stem cell transplantation (HSCT) and corresponding donors revealed that the donor, but not recipient, rs646564 variant in the PFKFB3 gene increased the risk of invasive pulmonary aspergillosis (IPA) after transplantation. The risk genotype impaired the expression of PFKFB3 by human macrophages in response to fungal infection, which was correlated with a defective activation of glycolysis and the ensuing antifungal effector functions. In patients with IPA, the risk genotype was associated with lower concentrations of cytokines in the bronchoalveolar lavage fluid samples. Collectively, these findings demonstrate the important contribution of genetic variation in PFKFB3 to the risk of IPA in patients undergoing HSCT and support its inclusion in prognostic tools to predict the risk of fungal infection in this clinical setting. IMPORTANCE The fungal pathogen Aspergillus fumigatus can cause severe and life-threatening forms of infection in immunocompromised patients. Activation of glycolysis is essential for innate immune cells to mount effective antifungal responses. In this study, we report the contribution of genetic variation in the key glycolytic activator 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) to the risk of invasive pulmonary aspergillosis (IPA) after allogeneic hematopoietic stem cell transplantation. The PFKFB3 genotype associated with increased risk of infection was correlated with an impairment of the antifungal effector functions of macrophages in vitro and in patients with IPA. This work highlights the clinical relevance of genetic variation in PFKFB3 to the risk of IPA and supports its integration in risk stratification and preemptive measures for patients at high risk of IPA.

Invasive pulmonary aspergillosis associated with viral pneumonitis.

The occurrence of invasive pulmonary aspergillosis (IPA) in critically ill patients with viral pneumonitis has increasingly been reported in recent years. Influenza-associated pulmonary aspergillosis (IAPA) and COVID-19-associated pulmonary aspergillosis (CAPA) are the two most common forms of this fungal infection. These diseases cause high mortality in patients, most of whom were previously immunocompetent. The pathogenesis of IAPA and CAPA is still not fully understood, but involves viral, fungal and host factors. In this article, we discuss several aspects regarding IAPA and CAPA, including their possible pathogenesis, the use of immunotherapy, and future challenges.

Invasive pulmonary aspergillosis associated with COVID-19 in a kidney transplant recipient.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might increase the risk of invasive pulmonary aspergillosis (IPA). Although several case reports and small series have been reported in the general population, scarce information is available regarding coronavirus disease 2019 (COVID-19)-associated IPA in the setting of solid organ transplantation. We describe a case of a kidney transplant recipient with severe COVID-19 that was subsequently diagnosed with probable IPA on the basis of the repeated isolation of Aspergillus fumigatus in sputum cultures, repeatedly increased serum (1 â†’ 3)-ß-d-glucan levels, and enlarging cavitary nodules in the CT scan. The evolution was favorable after initiation of isavuconazole and nebulized liposomal amphotericin B combination therapy and the withdrawal of immunosuppression.

Influenza Suppresses Neutrophil Recruitment to the Lung and Exacerbates Secondary Invasive Pulmonary Aspergillosis.

Aspergillus fumigatus is an environmental fungus that can cause invasive pulmonary aspergillosis when spores are inhaled into the respiratory tract and invade airway or lung tissue. Influenza is a common respiratory virus that can cause severe respiratory disease, and postinfluenza invasive pulmonary aspergillosis, which is becoming a well-recognized clinical problem, typically occurs in critically ill patients. Mice challenged with influenza A PR/8/34 H1N1 and subsequently challenged with A. fumigatus had increased fungal burden, viral burden, inflammation, and mortality compared with single infected mice. Neutrophil recruitment in the lung of superinfected mice was decreased; however, mice were not neutropenic, and there was no difference in absolute blood neutrophils between groups. Additionally, CXCL1 and CXCL2 were decreased in lungs of superinfected mice compared with controls. IFN levels were increased in mice that received influenza, and deletion of STAT1 resulted in decreased fungal burden, increased airway and lung neutrophils, and increased CXCL1 compared with wild-type mice, whereas deletion of STAT2 did not change fungal burden or airway neutrophilia compared with wild-type mice. These data demonstrate a mechanism by which influenza A-induced STAT1 signaling inhibits neutrophil recruitment and increases susceptibility to postinfluenza invasive pulmonary aspergillosis.

Three-Dimensional Light Sheet Fluorescence Microscopy of Lungs To Dissect Local Host Immune-Aspergillus fumigatus Interactions.

Aspergillus fumigatus is an opportunistic fungal pathogen that can cause life-threatening invasive lung infections in immunodeficient patients. The cellular and molecular processes of infection during onset, establishment, and progression of A. fumigatus infections are highly complex and depend on both fungal attributes and the immune status of the host. Therefore, preclinical animal models are of paramount importance to investigate and gain better insight into the infection process. Yet, despite their extensive use, commonly employed murine models of invasive pulmonary aspergillosis are not well understood due to analytical limitations. Here, we present quantitative light sheet fluorescence microscopy (LSFM) to describe fungal growth and the local immune response in whole lungs at cellular resolution within its anatomical context. We analyzed three very common murine models of pulmonary aspergillosis based on immunosuppression with corticosteroids, chemotherapy-induced leukopenia, or myeloablative irradiation. LSFM uncovered distinct architectures of fungal growth and degrees of tissue invasion in each model. Furthermore, LSFM revealed the spatial distribution, interaction, and activation of two key immune cell populations in antifungal defense: alveolar macrophages and polymorphonuclear neutrophils. Interestingly, the patterns of fungal growth correlated with the detected effects of the immunosuppressive regimens on the local immune cell populations. Moreover, LSFM demonstrates that the commonly used intranasal route of spore administration did not result in complete intra-alveolar deposition, as about 80% of fungal growth occurred outside the alveolar space. Hence, characterization by LSFM is more rigorous than by previously used methods employing murine models of invasive pulmonary aspergillosis and pinpoints their strengths and limitations.IMPORTANCE The use of animal models of infection is essential to advance our understanding of the complex host-pathogen interactions that take place during Aspergillus fumigatus lung infections. As in the case of humans, mice need to suffer an immune imbalance in order to become susceptible to invasive pulmonary aspergillosis (IPA), the most serious infection caused by A. fumigatus There are several immunosuppressive regimens that are routinely used to investigate fungal growth and/or immune responses in murine models of invasive pulmonary aspergillosis. However, the precise consequences of the use of each immunosuppressive model for the local immune populations and for fungal growth are not completely understood. Here, to pin down the scenarios involving commonly used IPA models, we employed light sheet fluorescence microscopy (LSFM) to analyze whole lungs at cellular resolution. Our results will be valuable to optimize and refine animal models to maximize their use in future research.

IL-27 Negatively Controls Antifungal Activity in a Model of Invasive Pulmonary Aspergillosis.

Invasive pulmonary aspergillosis is a life-threatening disease, particularly in immunocompromised patients, despite currently available therapy. IL-27 is an important regulatory cytokine in infection and immunity. However, its role in the pathogenesis of invasive pulmonary aspergillosis remains unknown. Here we found that Aspergillus fumigatus pulmonary infection induced an elevated production of IL-27 in the lung. As compared with wild-type (WT) mice, IL-27R (IL-27 receptor)-deficient mice developed less severe infection when challenged with A. fumigatus conidia, as evidenced by the decreased fungal colonization and pathology of lungs and the increased survival. IL-27R deficiency led to significantly higher production of IFN-γ in the lung after A. fumigatus infection, and the increased resistance to invasive pulmonary A. fumigatus infection in IL-27R-deficient mice was ablated by neutralizing IFN-γ. Importantly, neutralization of IL-27 could protect WT mice against invasive pulmonary A. fumigatus infection. Our data therefore suggest an important role of IL-27 in impairing anti-A. fumigatus host immunity, which may have translational implications in treating clinical cases of invasive pulmonary aspergillosis.

Infectious Complications in Patients Who Received High-Volume Plasma Exchange Prior to Liver Transplant: A Case Report.

Acute liver failure is a rare but life-threatening medical emergency. Despite advancements in medical management, mortality rates of acute liver failure remain high. Currently, liver transplant is the only definitive therapeutic option available. High-volume plasma exchange has been shown to increase transplant-free survival in patients with acute liver failure before liver transplant. However, the occurrence of infectious complications in patients who receive this treatment has not been well studied. We report 2 cases of severe opportunistic infections occurring within 30 days of transplant in patients who underwent high-volume plasma exchange before liver transplant.

Severe pulmonary infections complicating nivolumab treatment for lung cancer: a report of two cases.

BACKGROUND: Immunotherapy represents a recent milestone in the treatment of lung cancer, particularly with the rapidly expanding development of monoclonal antibodies targeting checkpoint inhibitors in the programmed cell death-1 (PD-1) pathway, such as nivolumab and pembrolizumab. Classical auto-immune side effects of these treatments, often called immune-related adverse events (irAEs), can affect multiple organs, including the lungs in which potentially life-threatening pneumonitis may require rapid treatment with high doses of corticosteroids. Nevertheless, the occurrence of severe infections in cancer patients treated with nivolumab, outside the context of immunosuppressive therapy, is a complication that has rarely been reported in the literature. CLINICAL CASES: We report two cases of severe pulmonary infection with unusual microbes, Mycobacterium tuberculosis and Aspergillus fumigatus, in patients treated with nivolumab for non-small cell lung cancer. CONCLUSION: Ruling out pulmonary infections may require extensive investigation, as these may have an atypical presentation due to immunomodulation. Furthermore, treating the patient with corticosteroids for immune-related pneumonia could lead to a fatal outcome in this context. This report highlights the importance of excluding the presence of opportunistic infections and tuberculosis before considering immune-related pulmonary toxicity with or without a history of prior corticosteroid use. These cases also emphasize the potential value of tuberculosis screening in patients treated with PD-1 checkpoint inhibitors.

Understanding the immunology of asthma: Pathophysiology, biomarkers, and treatments for asthma endotypes.

Asthma is a common disease in paediatrics and adults with a significant morbidity, mortality, and financial burden worldwide. Asthma is now recognized as a heterogeneous disease and emerging clinical and laboratory research has elucidated understanding of asthma's underlying immunology. The future of asthma is classifying asthma by endotype through connecting discernible characteristics with immunological mechanisms. This comprehensive review of the immunology of asthma details the currently known pathophysiology and clinical practice biomarkers in addition to forefront biologic and targeted therapies for all of the asthma endotypes. By understanding the immunology of asthma, practitioners will be able to diagnose patients by asthma endotype and provide personalized, biomarker-driven treatments to effectively control patients' asthma.

Neutrophil extracellular traps impair fungal clearance in a mouse model of invasive pulmonary aspergillosis.

Neutrophil extracellular traps (NETs) are formed by polymorphonuclear neutrophils (PMN) and contribute to the innate host defense by binding and killing bacterial and fungal pathogens. Because NET formation depends on histone hypercitrullination by peptidylarginine deiminase 4 (PAD4), we used PAD4 gene deficient (Pad4-/-) mice in a mouse model of invasive pulmonary aspergillosis (IPA) to address the contribution of NETs to the innate host defense in vivo. After the induction (24 h) of IPA by i.t. infection with Aspergillus fumigatus conidia, Pad4-/- mice revealed lower fungal burden in the lungs, accompanied by less acute lung injury, TNFα and citH3 compared to wildtype controls. These findings suggest that release of NETs contributes to tissue damage and limits control of fungal outgrowth. Thus inhibition of NETosis might be a useful strategy to maintain neutrophil function and avoid lung damage in patients suffering from IPA, especially in those suffering from preexisting pulmonary disease.

[Pulmonary Aspergillosis in immunocompetent patient]. / Aspergillose pulmonaire chez le patient immunocompétent.

Aspergillus is a group of molds which is found everywhere worldwide, exposition of human being is common. Most of immunocompetent people do not develop disease caused by Aspergillus. However, diseases in different forms may occur in certain conditions in immunocompetent patient. These diseases include hypersensitivity reactions, like allergic broncho-pulmonary aspergillosis, or infectious process like chronic pulmonary aspergillosis or invasive pulmonary aspergillosis. This article reviewed the clinical features of these diseases and the current available diagnostic techniques.

Aspergillus englobe un groupe de champignons ubiquitaires auquels l'être humain est quotidiennement exposé. Il est rarement pathogène chez le patient immunocompétent, cependant il peut être responsable de différentes formes de maladies dans certaines conditions. Ces pathologies comprennent des réactions d'hypersensibilité, comme l'aspergillose bronchopulmonaire allergique, ou des processus infectieux comme l'aspergillose pulmonaire chronique et l'aspergillose pulmonaire invasive aiguë. Cet article aborde les situations cliniques lors desquelles ces pathologies doivent être suspectées, tout en décrivant les caractéristiques de ces dernières et les moyens diagnostiques à disposition.

Microbiological Laboratory Testing in the Diagnosis of Fungal Infections in Pulmonary and Critical Care Practice. An Official American Thoracic Society Clinical Practice Guideline.

Background: Fungal infections are of increasing incidence and importance in immunocompromised and immunocompetent patients. Timely diagnosis relies on appropriate use of laboratory testing in susceptible patients.Methods: The relevant literature related to diagnosis of invasive pulmonary aspergillosis, invasive candidiasis, and the common endemic mycoses was systematically reviewed. Meta-analysis was performed when appropriate. Recommendations were developed using the Grading of Recommendations Assessment, Development, and Evaluation approach.Results: This guideline includes specific recommendations on the use of galactomannan testing in serum and BAL and for the diagnosis of invasive pulmonary aspergillosis, the role of PCR in the diagnosis of invasive pulmonary aspergillosis, the role of ß-d-glucan assays in the diagnosis of invasive candidiasis, and the application of serology and antigen testing in the diagnosis of the endemic mycoses.Conclusions: Rapid, accurate diagnosis of fungal infections relies on appropriate application of laboratory testing, including antigen testing, serological testing, and PCR-based assays.

The Metabolic Cytokine Adiponectin Inhibits Inflammatory Lung Pathology in Invasive Aspergillosis.

Systemic immunity and metabolism are coregulated by soluble factors, including the insulin-regulating adipose tissue cytokine adiponectin. How these factors impact detrimental inflammatory responses during fungal infection remains unknown. In this study, we observed that mortality, fungal burden, and tissue histopathology were increased in adiponectin-deficient mice in a neutropenic model of invasive aspergillosis. Lung RNA sequencing, quantitative RT-PCR, and subsequent pathway analysis demonstrated activation of inflammatory cytokine pathways with upstream regulation by IL-1 and TNF in adiponectin-deficient mice with decreased/inhibited anti-inflammatory genes/pathways, suggesting broad cytokine-mediated pathology along with ineffective fungal clearance. Quantitative RT-PCR analysis confirmed increased transcription of IL-1a, IL-6, IL-12b, IL-17A/F, and TNF in adiponectin-deficient mice at early time points postinfection, with a specific increase in intracellular TNF in alveolar macrophages. Although eosinophil recruitment and activation were increased in adiponectin-deficient mice, mortality was delayed, but not decreased, in mice deficient in both adiponectin and eosinophils. Interestingly, neutrophil depletion was required for increased inflammation in adiponectin-deficient mice in response to swollen/fixed conidia, suggesting that immune suppression enhances detrimental inflammation, whereas invasive fungal growth is dispensable. Our results suggest that adiponectin inhibits excessive lung inflammation in invasive aspergillosis. Our study has therefore identified the adiponectin pathway as a potential source for novel therapeutics in immune-compromised patients with detrimental immunity to invasive fungal infection.

Invasive pulmonary aspergillosis due to Aspergillus lentulus in an adult patient: A case report and literature review.

Aspergillus fumigatus is the commonest cause of pulmonary aspergillosis; however, a recently developed molecular genetic technique identified A. lentulus as a sibling species. Most of the isolates were found in solid organ recipients, often associated with a fatal outcome. Moreover, there is concern that A. lentulus has low susceptibility to multiple antifungal agents. Herein, we report an adult immunocompromised patient with proven invasive pulmonary aspergillosis (IPA) caused by A. lentulus, which was identified through molecular genetic analysis. The patient was diagnosed with IPA by bronchoscopy 3 weeks after initiating systemic corticosteroid therapy for anti-neutrophil cytoplasmic antibody-associated vasculitis. The clinical course of IPA due to A. lentulus showed improvement after treatment with the antifungal agent voriconazole. In summary, we report an adult immunocompromised patient without a history of transplantation who was diagnosed with IPA due to A. lentulus successfully treated with voriconazole, and we also report the findings of a literature review on IPA caused by A. lentulus.