ABSTRACT
Infections caused by parasites and fungi can trigger the cytokine storm syndrome (CSS). These infections causing CSS can occur together with acquired immunodeficiencies, lymphomas, the use of immunosuppressive medications, transplant recipients, cancer, autoinflammatory, and autoimmune diseases or less frequently in healthy individuals. Histoplasma, Leishmania, Plasmodium, and Toxoplasma are the most frequent organisms associated with a CSS. It is very important to determine a previous travel history when evaluating a patient with a CSS triggered by these organisms as this may be the clue to the causal agent. Even though CSS is treated with specific therapies, an effort to find the causal organism should be carried out since the treatment of the infectious organism may stop the CSS. Diagnosing a CSS in the presence of parasitic or fungal sepsis should also lead to the study of an altered cytotoxic or hemophagocytic response in the susceptible host.
Subject(s)
Cytokine Release Syndrome , Humans , Cytokine Release Syndrome/immunology , Cytokine Release Syndrome/microbiology , Mycoses/microbiology , Mycoses/immunology , Animals , Parasitic Diseases/immunology , Parasitic Diseases/parasitology , Parasitic Diseases/complications , Cytokines/metabolismABSTRACT
Programmed death-ligand 1 interacts with fungal ribosomal Rpl20b in phagosomes and induces interleukin-10 secretion.
Subject(s)
B7-H1 Antigen , Inflammation , Mycoses , B7-H1 Antigen/immunology , B7-H1 Antigen/metabolism , Inflammation/immunology , Humans , Mycoses/immunology , Mycoses/microbiology , Animals , Mice , Ribosomal Proteins/immunologyABSTRACT
Global amphibian declines are compounded by deadly disease outbreaks caused by the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Much has been learned about the roles of amphibian skin-produced antimicrobial components and microbiomes in controlling Bd, yet almost nothing is known about the roles of skin-resident immune cells in anti-Bd defenses. Mammalian mast cells reside within and serve as key immune sentinels in barrier tissues like skin. Accordingly, we investigated the roles of Xenopus laevis frog mast cells during Bd infections. Our findings indicate that enrichment of X. laevis skin mast cells confers anti-Bd protection and ameliorates the inflammation-associated skin damage caused by Bd infection. This includes a significant reduction in infiltration of Bd-infected skin by neutrophils, promoting mucin content within cutaneous mucus glands, and preventing Bd-mediated changes to skin microbiomes. Mammalian mast cells are known for their production of the pleiotropic interleukin-4 (IL4) cytokine and our findings suggest that the X. laevis IL4 plays a key role in manifesting the effects seen following cutaneous mast cell enrichment. Together, this work underscores the importance of amphibian skin-resident immune cells in anti-Bd defenses and illuminates a novel avenue for investigating amphibian host-chytrid pathogen interactions.
Subject(s)
Batrachochytrium , Mast Cells , Skin , Xenopus laevis , Animals , Mast Cells/immunology , Mast Cells/microbiology , Mast Cells/metabolism , Xenopus laevis/microbiology , Xenopus laevis/immunology , Skin/microbiology , Skin/immunology , Mycoses/immunology , Mycoses/veterinary , Mycoses/microbiology , MicrobiotaABSTRACT
Many threats to biodiversity cannot be eliminated; for example, invasive pathogens may be ubiquitous. Chytridiomycosis is a fungal disease that has spread worldwide, driving at least 90 amphibian species to extinction, and severely affecting hundreds of others1-4. Once the disease spreads to a new environment, it is likely to become a permanent part of that ecosystem. To enable coexistence with chytridiomycosis in the field, we devised an intervention that exploits host defences and pathogen vulnerabilities. Here we show that sunlight-heated artificial refugia attract endangered frogs and enable body temperatures high enough to clear infections, and that having recovered in this way, frogs are subsequently resistant to chytridiomycosis even under cool conditions that are optimal for fungal growth. Our results provide a simple, inexpensive and widely applicable strategy to buffer frogs against chytridiomycosis in nature. The refugia are immediately useful for the endangered species we tested and will have broader utility for amphibian species with similar ecologies. Furthermore, our concept could be applied to other wildlife diseases in which differences in host and pathogen physiologies can be exploited. The refugia are made from cheap and readily available materials and therefore could be rapidly adopted by wildlife managers and the public. In summary, habitat protection alone cannot protect species that are affected by invasive diseases, but simple manipulations to microhabitat structure could spell the difference between the extinction and the persistence of endangered amphibians.
Subject(s)
Anura , Chytridiomycota , Disease Resistance , Endangered Species , Mycoses , Refugium , Animals , Anura/immunology , Anura/microbiology , Anura/physiology , Body Temperature/immunology , Body Temperature/physiology , Body Temperature/radiation effects , Chytridiomycota/immunology , Chytridiomycota/pathogenicity , Chytridiomycota/physiology , Disease Resistance/immunology , Disease Resistance/physiology , Disease Resistance/radiation effects , Ecosystem , Mycoses/veterinary , Mycoses/microbiology , Mycoses/immunology , Sunlight , Animals, Wild/immunology , Animals, Wild/microbiology , Animals, Wild/physiology , Introduced SpeciesABSTRACT
Fungal infections are incurring high risks in a range from superficial mucosal discomforts (such as oropharyngeal candidiasis and vulvovaginal candidiasis) to disseminated life-threatening diseases (such as invasive pulmonary aspergillosis and cryptococcal meningitis) and becoming a global health problem in especially immunodeficient population. The major obstacle to conquer fungal harassment lies in the presence of increasing resistance to conventional antifungal agents used in newly clinically isolated strains. Although recombinant cytokines and mono-/poly-clonal antibodies are added into antifungal armamentarium, more effective antimycotic drugs are exceedingly demanded. It is comforting that the development of fungal vaccines and adjuvants opens up a window to brighten the prospective way in the diagnosis, prevention and treatment of fungal assaults. In this review, we focus on the progression of several major fungal vaccines devised for the control of Candida spp., Aspergillus spp., Cryptococcus spp., Coccidioides spp., Paracoccidioides spp., Blastomyces spp., Histoplasma spp., Pneumocystis spp. as well as the adjuvants adopted. We then expound the interaction between fungal vaccines/adjuvants and host innate (macrophages, dendritic cells, neutrophils), humoral (IgG, IgM and IgA) and cellular (Th1, Th2, Th17 and Tc17) immune responses which generally experience immune recognition of pattern recognition receptors, activation of immune cells, and clearance of invaded fungi. Furthermore, we anticipate an in-depth understanding of immunomodulatory properties of univalent and multivalent vaccines against diverse opportunistic fungi, providing helpful information in the design of novel fungal vaccines and adjuvants.
Subject(s)
Adjuvants, Immunologic , Fungal Vaccines , Mycoses , Fungal Vaccines/immunology , Humans , Mycoses/prevention & control , Mycoses/immunology , Animals , Fungi/immunologyABSTRACT
Allergic fungal rhinosinusitis (AFRS) is a subtype of chronic rhinosinusitis, characterized by excessive immune responses to environmental molds or fungi. The diagnosis and classification of AFRS into systemic and local types remain clinically challenging due to overlapping characteristics. This study investigated the prevalence of AFRS, its manifestation and associated factors in systemic and local AFRS. A total of 200 patients diagnosed with fungal rhinosinusitis underwent both skin provocation tests (SPT) and nasal provocation tests (NPT) to confirm AFRS and classify systemic and local types. Patients were considered to have AFRS if either the SPT or NPT was positive. Among these, patients with systemic AFRS were those who had a SPT positive. Local AFRS was when patients had a negative SPT and a positive NPT. Medical history, serum total IgE level, nasal endoscopy examinations, and CT scans were also recorded. Most patients were female (65.8%), with a mean age of 55.6 years (SDâ =â 14.4). Based on the SPT and NPT results, 31% of patients (n = 62) were diagnosed with AFRS. Among these, 54.8% (n = 34) had systemic AFRS, while 45.2% (n = 28) had local AFRS. Patients with AFRS exhibited significantly higher levels of total IgE, eosinophils, and more pronounced signs and symptoms compared to those without AFRS. However, no statistically significant differences were observed between patients with systemic AFRS and those with local AFRS. AFRS was prevalent in our study. Among patients with AFRS, both systemic AFRS and local AFRS were also prevalent. While allergic indicators and clinical presentations can aid in AFRS diagnosis, minimal distinctions were observed between systemic and local AFRS. A comprehensive assessment incorporating both local and systemic allergic responses through provocation tests, such as a combination of skin and nasal tests, is imperative for optimizing AFRS diagnosis and management.
Subject(s)
Rhinitis, Allergic , Sinusitis , Skin Tests , Humans , Female , Male , Sinusitis/immunology , Sinusitis/microbiology , Sinusitis/complications , Sinusitis/epidemiology , Sinusitis/diagnosis , Middle Aged , Rhinitis, Allergic/immunology , Rhinitis, Allergic/epidemiology , Rhinitis, Allergic/complications , Rhinitis, Allergic/diagnosis , Adult , Aged , Nasal Provocation Tests , Immunoglobulin E/blood , Prevalence , Mycoses/immunology , Mycoses/epidemiology , Mycoses/diagnosis , Mycoses/complications , Allergic Fungal SinusitisABSTRACT
PURPOSE OF THE REVIEW: Fungal sensitizations have been associated with hypersensitivity reactions with variable levels of evidence available to link types of fungi with human disease. We conducted systematic reviews of the literature to identify the strength of evidence linking lesser-studied fungi for which there are commercially available extracts to identify populations in which they were useful in clinical practice. RECENT FINDINGS: Excluding five fungi for which hundreds of articles were identified, there are 54 articles on the remaining fungi with clinical data. For 12 of the fungi, the prevalence of fungal sensitization varies in different hypersensitivity disorders due to factors related to geographic areas, age, and other underlying medical conditions. There were no studies linking seven genera to human disease. Most of the commercially available fungal extracts are uncommonly associated with hypersensitivity reactions in humans. Specific extracts may be useful in particular disease states such as allergic fungal sinusitis or allergic bronchopulmonary mycosis, or when routine testing fails to identify a cause of uncontrolled disease, such as in asthma.
Subject(s)
Fungi , Hypersensitivity , Humans , Fungi/immunology , Hypersensitivity/immunology , Antigens, Fungal/immunology , Allergens/immunology , Mycoses/immunologyABSTRACT
Recent case reports and epidemiological data suggest that fungal infections represent an underappreciated complication among people with severe COVID-19. However, the frequency of fungal colonization in patients with COVID-19 and associations with specific immune responses in the airways remain incompletely defined. We previously generated a single-cell RNA-sequencing data set characterizing the upper respiratory microenvironment during COVID-19 and mapped the relationship between disease severity and the local behavior of nasal epithelial cells and infiltrating immune cells. Our previous study, in agreement with findings from related human cohorts, demonstrated that a profound deficiency in host immunity, particularly in type I and type III interferon signaling in the upper respiratory tract, is associated with rapid progression to severe disease and worse clinical outcomes. We have now performed further analysis of this cohort and identified a subset of participants with severe COVID-19 and concurrent detection of Candida species-derived transcripts within samples collected from the nasopharynx and trachea. Here, we present the clinical characteristics of these individuals. Using matched single-cell transcriptomic profiles of these individuals' respiratory mucosa, we identify epithelial immune signatures suggestive of IL17 stimulation and anti-fungal immunity. Further, we observe a significant expression of anti-fungal inflammatory cascades in the nasal and tracheal epithelium of all participants who went on to develop severe COVID-19, even among participants without detectable genetic material from fungal pathogens. Together, our data suggest that IL17 stimulation-in part driven by Candida colonization-and blunted interferon signaling represent a common feature of severe COVID-19 infection. IMPORTANCE: In this paper, we present an analysis suggesting that symptomatic and asymptomatic fungal coinfections can impact patient disease progression during COVID-19 hospitalization. By looking into the presence of other pathogens and their effect on the host immune response during COVID-19 hospitalizations, we aim to offer insight into an underestimated scenario, furthering our current knowledge of determinants of severity that could be considered for future diagnostic and intervention strategies.
Subject(s)
COVID-19 , Coinfection , Epithelial Cells , Interferon Type I , Interleukin-17 , SARS-CoV-2 , Humans , Interleukin-17/metabolism , Interleukin-17/genetics , Interleukin-17/immunology , COVID-19/immunology , Coinfection/immunology , Coinfection/microbiology , Coinfection/virology , Interferon Type I/metabolism , Interferon Type I/immunology , Male , SARS-CoV-2/immunology , Middle Aged , Female , Epithelial Cells/immunology , Epithelial Cells/microbiology , Adult , Nasal Mucosa/immunology , Nasal Mucosa/microbiology , Aged , Nasopharynx/microbiology , Candidiasis/immunology , Candidiasis/microbiology , Mycoses/immunologyABSTRACT
Patients with burn injury and inhalation injury are highly susceptible to infectious complications, including opportunistic pathogens, due to the loss of skin cover and mucosal damage of respiratory tract as well as the disruption of homeostasis. This case report, a 34-year-old man suffered critical burns, provides the first literature description of triple-impact immunoparalysis (critical burns, inhalation injury, and SARS-CoV-2 infection), leading to a lethal multifocal infection caused by several fungi including very rare environmental representatives Metschnikowia pulcherrima and Wickerhamomyces anomalus. The co-infection by these common environmental yeasts in a human is unique and has not yet been described in the literature. Importantly, our patient developed refractory septic shock and died despite targeted antifungal therapy including the most potent current antifungal agent-isavuconazole. It can be assumed that besides immunoparalysis, effectiveness of therapy by isavuconazole was impaired by the large distribution volume in this case. As this is a common situation in intensive care patients, routine monitoring of plasmatic concentration of isavuconazole can be helpful in personalization of the treatment and dose optimization. Whatmore, many fungal species often remain underdiagnosed during infectious complications, which could be prevented by implementation of new methods, such as next-generation sequencing, into clinical practice.
Subject(s)
Antifungal Agents , COVID-19 , Humans , Adult , Male , Antifungal Agents/therapeutic use , COVID-19/immunology , COVID-19/complications , Coinfection/microbiology , Coinfection/drug therapy , Coinfection/immunology , Burns/complications , Burns/microbiology , Sepsis/drug therapy , Sepsis/microbiology , Sepsis/immunology , Fatal Outcome , SARS-CoV-2/immunology , Nitriles/therapeutic use , Mycoses/drug therapy , Mycoses/microbiology , Mycoses/immunology , Mycoses/diagnosis , Pyridines/therapeutic use , Triazoles/therapeutic use , Saccharomycetales/genetics , Saccharomycetales/drug effects , Saccharomycetales/immunologyABSTRACT
Anti-interferon-γ autoantibody (AIGA) syndrome may be the basis of disseminated Talaromyces marneffei infection in human immunodeficiency virus (HIV)-negative adults. However, the pathogenesis of Th1 cell immunity in T. marneffei infection with AIGA syndrome is unknown. A multicenter study of HIV-negative individuals with T. marneffei infection was conducted between September 2018 and September 2020 in Guangdong and Guangxi, China. Patients were divided into AIGA-positive (AP) and AIGA-negative (AN) groups according to the AIGA titer and neutralizing activity. The relationship between AIGA syndrome and Th1 immune deficiency was investigated by using AP patient serum and purification of AIGA. Fifty-five HIV-negative adults with disseminated T. marneffei infection who were otherwise healthy were included. The prevalence of AIGA positivity was 83.6%. Based on their AIGA status, 46 and 9 patients were assigned to the AP and AN groups, respectively. The levels of Th1 cells, IFN-γ, and T-bet were higher in T. marneffei-infected patients than in healthy controls. However, the levels of CD4+ T-cell STAT-1 phosphorylation (pSTAT1) and Th1 cells were lower in the AP group than in the AN group. Both the serum of patients with AIGA syndrome and the AIGA purified from the serum of patients with AIGA syndrome could reduce CD4+ T-cell pSTAT1, Th1 cell differentiation and T-bet mRNA, and protein expression. The Th1 cell immune response plays a pivotal role in defense against T. marneffei infection in HIV-negative patients. Inhibition of the Th1 cell immune response may be an important pathological effect of AIGA syndrome.IMPORTANCEThe pathogenesis of Th1 cell immunity in Talaromyces marneffei infection with anti-interferon-γ autoantibody (AIGA) syndrome is unknown. This is an interesting study addressing an important knowledge gap regarding the pathogenesis of T. marneffei in non-HIV positive patients; in particular patients with AIGA. The finding of the Th1 cell immune response plays a pivotal role in defense against T. marneffei infection in HIV-negative patients, and inhibition of the Th1 cell immune response may be an important pathological effect of AIGA syndrome, which presented in this research could help bridge the current knowledge gap.
Subject(s)
Autoantibodies , Interferon-gamma , Mycoses , Talaromyces , Th1 Cells , Humans , Talaromyces/immunology , Th1 Cells/immunology , Interferon-gamma/immunology , Autoantibodies/immunology , Autoantibodies/blood , Male , Adult , Female , China , Mycoses/immunology , Mycoses/microbiology , Middle Aged , T-Box Domain Proteins/genetics , T-Box Domain Proteins/immunology , STAT1 Transcription Factor/immunology , STAT1 Transcription Factor/geneticsABSTRACT
BACKGROUND: Autoantibodies against interleukin-12 (anti-interleukin-12) are often identified in patients with thymoma, but opportunistic infections develop in only some of these patients. Interleukin-12 (with subunits p40 and p35) shares a common subunit with interleukin-23 (subunits p40 and p19). In a patient with disseminated Burkholderia gladioli infection, the identification of both anti-interleukin-23 and anti-interleukin-12 prompted further investigation. METHODS: Among the patients (most of whom had thymoma) who were known to have anti-interleukin-12, we screened for autoantibodies against interleukin-23 (anti-interleukin-23). To validate the potential role of anti-interleukin-23 with respect to opportunistic infection, we tested a second cohort of patients with thymoma as well as patients without either thymoma or known anti-interleukin-12 who had unusual infections. RESULTS: Among 30 patients with anti-interleukin-12 who had severe mycobacterial, bacterial, or fungal infections, 15 (50%) also had autoantibodies that neutralized interleukin-23. The potency of such neutralization was correlated with the severity of these infections. The neutralizing activity of anti-interleukin-12 alone was not associated with infection. In the validation cohort of 91 patients with thymoma, the presence of anti-interleukin-23 was associated with infection status in 74 patients (81%). Overall, neutralizing anti-interleukin-23 was detected in 30 of 116 patients (26%) with thymoma and in 30 of 36 patients (83%) with disseminated, cerebral, or pulmonary infections. Anti-interleukin-23 was present in 6 of 32 patients (19%) with severe intracellular infections and in 2 of 16 patients (12%) with unusual intracranial infections, including Cladophialophora bantiana and Mycobacterium avium complex. CONCLUSIONS: Among patients with a variety of mycobacterial, bacterial, or fungal infections, the presence of neutralizing anti-interleukin-23 was associated with severe, persistent opportunistic infections. (Funded by the National Institute of Allergy and Infectious Diseases and others.).
Subject(s)
Autoantibodies , Immunologic Deficiency Syndromes , Interleukin-23 , Opportunistic Infections , Adult , Humans , Autoantibodies/immunology , Immunologic Deficiency Syndromes/immunology , Interleukin-12/antagonists & inhibitors , Interleukin-12/immunology , Interleukin-23/antagonists & inhibitors , Interleukin-23/immunology , Mycoses/immunology , Opportunistic Infections/immunology , Thymoma/immunology , Thymus Neoplasms/immunology , Antibodies, Neutralizing/immunology , Bacterial Infections/immunologyABSTRACT
INTRODUCTION: Diverse pathogens (viral, bacterial, fungal) have been associated with Alzheimer's disease (AD) and related traits in various studies. This suggests that compromised immunity, rather than specific microbes, may play a role in AD by increasing an individual's vulnerability to various infections, which could contribute to neurodegeneration. If true, then vaccines that have heterologous effects on immunity, extending beyond protection against the targeted disease, may hold a potential for AD prevention. METHODS: We evaluated the associations of common adult infections (herpes simplex, zoster (shingles), pneumonia, and recurrent mycoses), and vaccinations against shingles and pneumonia, with the risks of AD and other dementias in a pseudorandomized sample of the Health and Retirement Study (HRS). RESULTS: Shingles, pneumonia and mycoses, diagnosed between ages 65 and 75, were all associated with significantly increased risk of AD later in life, by 16 %-42 %. Pneumococcal and shingles vaccines administered between ages 65-75 were both associated with a significantly lower risk of AD, by 15 %-21 %. These effects became less pronounced when AD was combined with other dementias. DISCUSSION: Our findings suggest that both the pneumococcal polysaccharide vaccine and the live attenuated zoster vaccine can offer significant protection against AD. It remains to be determined if non-live shingles vaccine has a similar beneficial effect on AD. This study also found significant associations of various infections with the risk of AD, but not with the risks of other dementias. This indicates that vulnerability to infections may play a more significant role in AD than in other types of dementia, which warrants further investigation.
Subject(s)
Alzheimer Disease , Humans , Alzheimer Disease/immunology , Alzheimer Disease/prevention & control , Aged , Male , Female , Herpes Zoster/prevention & control , Herpes Zoster/immunology , Herpes Zoster Vaccine/immunology , Pneumonia/prevention & control , Pneumonia/immunology , Pneumonia/microbiology , Mycoses/prevention & control , Mycoses/immunology , Aged, 80 and over , Pneumococcal Vaccines/immunology , Risk FactorsABSTRACT
Fungi are the cause of more than a billion infections in humans every year, although their interactions with the host are still neglected compared to bacteria. Major systemic fungal infections are very unusual in the healthy population, due to the long history of coevolution with the human host. Humans are routinely exposed to environmental fungi and can host a commensal mycobiota, which is increasingly considered as a key player in health and disease. Here, we review the current knowledge on host-fungi coevolution and the factors that regulate their interaction. On one hand, fungi have learned to survive and inhabit the host organisms as a natural ecosystem, on the other hand, the host immune system finely tunes the response toward fungi. In turn, recognition of fungi as commensals or pathogens regulates the host immune balance in health and disease. In the human gut ecosystem, yeasts provide a fingerprint of the transient microbiota. Their status as passengers or colonizers is related to the integrity of the gut barrier and the risk of multiple disorders. Thus, the study of this less known component of the microbiota could unravel the rules of the transition from passengers to colonizers and invaders, as well as their dependence on the innate component of the host's immune response. This article is categorized under: Infectious Diseases > Environmental Factors Immune System Diseases > Environmental Factors Infectious Diseases > Molecular and Cellular Physiology.
Subject(s)
Host-Pathogen Interactions , Humans , Host-Pathogen Interactions/immunology , Mycoses/immunology , Mycoses/microbiology , Yeasts , Gastrointestinal Microbiome/immunology , Gastrointestinal Microbiome/physiology , Fungi/pathogenicity , Fungi/immunology , Fungi/physiology , Animals , Biological EvolutionABSTRACT
PURPOSE OF REVIEW: The burden of invasive fungal infection is increasing worldwide, largely due to a growing population at-risk. Most serious human fungal pathogens enter the host via the respiratory tract. Early identification and treatment of invasive fungal respiratory infections (IFRIs) in the immunocompromised host saves lives. However, their accurate diagnosis is a difficult challenge for clinicians and mortality remains high. RECENT FINDINGS: This article reviews IFRIs, focussing on host susceptibility factors, clinical presentation, and mycological diagnosis. Several new diagnostic tools are coming of age including molecular diagnostics and point-of-care antigen tests. As diagnosis of IFRI relies heavily on invasive procedures like bronchoalveolar lavage and lung biopsy, several novel noninvasive diagnostic techniques are in development, such as metagenomics, 'volatilomics' and advanced imaging technologies. SUMMARY: Where IFRI cannot be proven, clinicians must employ a 'weights-of-evidence' approach to evaluate host factors, clinical and mycological data. Implementation studies are needed to understand how new diagnostic tools can be best applied within clinical pathways. Differentiating invasive infection from colonization and identifying antifungal resistance remain key challenges. As our diagnostic arsenal expands, centralized clinical mycology laboratories and efforts to ensure access to new diagnostics in low-resource settings will become increasingly important.
Subject(s)
Immunocompromised Host , Invasive Fungal Infections , Respiratory Tract Infections , Humans , Biopsy , Invasive Fungal Infections/diagnosis , Invasive Fungal Infections/immunology , Invasive Fungal Infections/microbiology , Mycoses/diagnosis , Mycoses/immunology , Mycoses/microbiology , Respiratory Tract Infections/diagnosis , Respiratory Tract Infections/immunology , Respiratory Tract Infections/microbiology , Bronchoalveolar Lavage , Bronchoalveolar Lavage Fluid/microbiology , Lung/microbiology , Lung/pathologyABSTRACT
The non-pathogenic TH17 subset of helper T cells clears fungal infections, whereas pathogenic TH17 cells cause inflammation and tissue damage; however, the mechanisms controlling these distinct responses remain unclear. Here we found that fungi sensing by the C-type lectin dectin-1 in human dendritic cells (DCs) directed the polarization of non-pathogenic TH17 cells. Dectin-1 signaling triggered transient and intermediate expression of interferon (IFN)-ß in DCs, which was mediated by the opposed activities of transcription factors IRF1 and IRF5. IFN-ß-induced signaling led to integrin αvß8 expression directly and to the release of the active form of the cytokine transforming growth factor (TGF)-ß indirectly. Uncontrolled IFN-ß responses as a result of IRF1 deficiency induced high expression of the IFN-stimulated gene BST2 in DCs and restrained TGF-ß activation. Active TGF-ß was required for polarization of non-pathogenic TH17 cells, whereas pathogenic TH17 cells developed in the absence of active TGF-ß. Thus, dectin-1-mediated modulation of type I IFN responses allowed TGF-ß activation and non-pathogenic TH17 cell development during fungal infections in humans.
Subject(s)
Dendritic Cells , Interferon Type I , Mycoses , Humans , Cytokines/metabolism , Dendritic Cells/metabolism , Interferon Type I/metabolism , Lectins, C-Type/genetics , Lectins, C-Type/metabolism , Th17 Cells/metabolism , Transforming Growth Factor beta/metabolism , Mycoses/immunologyABSTRACT
Fungal peritonitis is an inflammatory condition of the peritoneum which occurs secondary to peritoneal dialysis. Most cases of peritonitis are caused by microbial invasion into the peritoneal cavity, resulting in high morbidity and mortality. Unlike bacterial peritonitis, little is known on fungal peritonitis. Card9, an adapter protein, plays a critical role in anti-fungal immunity. In this study, by using zymosan-induced peritonitis and C. albicans-induced peritonitis mouse model, we demonstrated that fungal peritonitis was exacerbated in Card9-/- mice, compared with WT mice. Next, we found the autophagy activation of peritonealmacrophages was impaired in Card9-/- peritonitis mice. The autophagy agonist, MG132, ameliorated peritonitis in Card9-/- mice. The result of microarray analysis indicates Malt1 was significantly decreased in Card9-/- peritonitis mice. Furthermore, we demonstrated that Malt1 interacts with P62 and mediates the function of P62 to clear ubiquitinated proteins. After overexpression of Malt1, impaired autophagy activation caused by Card9 deficient was significantly rescued. Together, our results indicate that Card9 protects fungal peritonitis by regulating Malt1-mediated autophagy in macrophages. Our research provides a new idea for the pathogenesis of fungal peritonitis, which is of great significance for the clinical treatment of fungal peritonitis.
Subject(s)
CARD Signaling Adaptor Proteins , Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein , Mycoses/immunology , Peritonitis , Adaptor Proteins, Signal Transducing/metabolism , Animals , Autophagy , CARD Signaling Adaptor Proteins/genetics , CARD Signaling Adaptor Proteins/metabolism , Macrophages/metabolism , Mice , Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein/genetics , Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein/metabolism , Peritonitis/immunology , ZymosanABSTRACT
Eosinophils are innate immune cells typically associated with allergic and parasitic diseases. However, in recent years, eosinophils have also been ascribed a role in keeping homeostasis and in fighting several infectious diseases. Indeed, these cells circulate as mature cells in the blood and can be quickly recruited to the infected tissue. Moreover, eosinophils have all the necessary cellular equipment such as pattern recognition receptors (PRRs), pro-inflammatory cytokines, anti-bacterial proteins, and DNA traps to fight pathogens and promote an efficient immune response. This review summarizes some of the updated information on the role of eosinophils' direct and indirect mediated interactions with pathogens.
Subject(s)
Bacterial Infections , Eosinophils , Mycoses , Virus Diseases , Bacterial Infections/immunology , Cytokines/metabolism , Eosinophils/immunology , Humans , Immunity, Innate , Mycoses/immunology , Receptors, Pattern Recognition/metabolism , Virus Diseases/immunologyABSTRACT
Fungal diseases of fish are a significant economic problem in aquaculture. Using high-throughput expression analysis, we identified potential transcript markers in primary head kidney and secondary embryonic cells from salmonid fish after stimulation with the inactivated fungi Mucor hiemalis and Fusarium aveneacium and with purified fungal molecular patterns. The transcript levels of most of the 45 selected genes were altered in head-kidney cells after 24 h of stimulation with fungal antigens. Stimulation with the inactivated fungus M. hiemalis induced the most pronounced transcriptional changes, including the pathogen receptor-encoding genes CLEC18A and TLR22, the cytokine-encoding genes IL6 and TNF, and the gene encoding the antimicrobial peptide LEAP2. In parallel, we analyzed the total GlcNAcylation status of embryonic salmonid cells with or without stimulation with inactivated fungi. O-GlcNAcylation modulates gene expression, intracellular protein, and signal activity, but we detected no significant differences after a 3-h stimulation. A pathway analysis tool identified the "apoptosis of leukocytes" based on the expression profile 24 h after fungal stimulation. Fluorescence microscopy combined with flow cytometry revealed apoptosis in 50 % of head-kidney leukocytes after 3 h stimulation with M. hiemalis, but this level decreased by > 5% after 24 h of stimulation. The number of apoptotic cells significantly increased in all blood cells after a 3-h stimulation with fungal molecular patterns compared to unstimulated controls. This in vitro approach identified transcript-based parameters that were strongly modulated by fungal infections of salmonid fish.
Subject(s)
Acetylglucosamine/chemistry , Fusarium/immunology , Mucor/immunology , Mycoses/immunology , Oncorhynchus mykiss/microbiology , Salmon/microbiology , Animals , Antimicrobial Cationic Peptides/genetics , Apoptosis/physiology , Fish Diseases/microbiology , Gene Expression Regulation, Developmental/genetics , Head Kidney/metabolism , Interleukin-6/genetics , Lectins, C-Type/genetics , Protein Processing, Post-Translational , Toll-Like Receptor 3/genetics , Tumor Necrosis Factor-alpha/geneticsABSTRACT
Tocilizumab decreases inflammatory response in the cytokine storm which is one of the mechanisms behind the development of ARDS in COVID-19 patients. The objective of our study was to determine response of tocilizumab in patients suffering from COVID-19 by analyzing clinical parameters and inflammatory markers. A single-arm observational retrospective study was conducted from March 15, 2020 to March 15, 2021. Clinical outcomes in terms of mortality, weaning from mechanical ventilator, improvement in laboratory parameters including inflammatory cytokines, and length of hospital stay were documented. Reduction in values of inflammatory markers, and patients discharged home in stable condition were defined as an improvement after tocilizumab administration. A total of 514 patients received tocilizumab, majority of whom were critically sick 333 (64.8%). Out of the total sample 363 (70.6%) patients were discharged home in stable condition. Overall mean length of stay was 11.50 ± 8.4 days. There was significant difference in length of stay of patients who required invasive mechanical ventilation as compared to those who were kept only on supplemental oxygen (p < 0.05). Patients who were discharged home showed significant improvement in inflammatory markers and neutrophil to lymphocyte ratio as compared to those who expired (p < 0.05). A total of 21 (4.1%) patients had positive blood culture while 57 (11.1%) had positive culture of tracheal aspirate. Hence, tocilizumab is found to be a reasonable therapeutic option for worsening COVID-19 pneumonia by decreasing the need for mechanical ventilation. However, it is associated with adverse events including bacterial and fungal infections.