Primary Cutaneous Aspergillosis in a Patient with CARD9 Deficiency and Aspergillus Susceptibility of Card9 Knockout Mice

Innate immune signal transduction pathways to fungal infection: Components and regulation

Candida species are significant causes of mucosal and systemic infections in immune compromised populations, including HIV-infected individuals and cancer patients. Drug resistance and toxicity have limited the use of anti-fungal drugs. A good comprehension of the nature of the immune responses to the pathogenic fungi will aid in the developing of new approaches to the treatment of fungal diseases. In recent years, extensive research has been done to understand the host defending systems to fungal infections. In this review, we described how pattern recognition receptors senses the cognate fungal ligands and the cellular and molecular mechanisms of anti-fungal innate immune responses. Furthermore, particular focus is placed on how anti-fungal signal transduction cascades are being activated for host defense and being modulated to better treat the infections in terms of immunotherapy. Understanding the role that these pathways have in mediating host anti-fungal immunity will be crucial for future therapeutic development.

From Mendel to mycoses: Immuno-genomic warfare at the human-fungus interface

Fungi are opportunists: They particularly require a defect of immunity to cause severe or disseminated disease. While often secondary to an apparent iatrogenic cause, fungal diseases do occur in the absence of one, albeit infrequently. These rare cases may be due to an underlying genetic immunodeficiency that can present variably in age of onset, severity, or other infections, and in the absence of a family history of disease. They may also be due to anti-cytokine autoantibodies. This review provides a background on how human genetics or autoantibodies underlie cases of susceptibility to severe or disseminated fungal disease. Subsequently, the lessons learned from these inborn errors of immunity marked by fungal disease (IEI-FD) provide a framework to begin to mechanistically decipher fungal syndromes, potentially paving the way for precision therapy of the mycoses.

Role of CARD9 in Cell- and Organ-Specific Immune Responses in Various Infections

The caspase recruitment domain-containing protein 9 (CARD9) is an intracellular adaptor protein that is abundantly expressed in cells of the myeloid lineage, such as neutrophils, macrophages, and dendritic cells. CARD9 plays a critical role in host immunity against infections caused by fungi, bacteria, and viruses. A CARD9 deficiency impairs the production of inflammatory cytokines and chemokines as well as migration and infiltration, thereby increasing susceptibility to infections. However, CARD9 signaling varies depending on the pathogen causing the infection. Furthermore, different studies have reported altered CARD9-mediated signaling even with the same pathogen. Therefore, this review focuses on and elucidates the current literature on varied CARD9 signaling in response to various infectious stimuli in humans and experimental mice models.

CARD9 deficiency with allergic bronchopulmonary aspergillosis (ABPA)-like presentation: a case report

PURPOSE

We present a patient with CARD9 deficiency and allergic bronchopulmonary aspergillosis (ABPA)-like presentation.

METHODS

Following medical history taking and routine laboratory investigations, an inborn error of immunity was suspected, and the responsible variant was identified using Whole Exome Sequencing and confirmed by Sanger sequencing.

RESULTS

A 14-year-old Iranian female presented with a history of chest pain, productive cough, dyspnea, malaise, and recurrent fever. Imaging by computed tomography (CT scan), chest X-ray (CXR), bronchoscopy, transbronchial lung biopsy (TBLB), and histopathology findings led to a diagnosis of ABPA-like presentation. The genetic study showed an autosomal recessive homozygous mutation in the CARD9 gene. Clinical remission was achieved following the administration of voriconazole, which was continued as prophylaxis.

CONCLUSIONS

This is the first-time report of a patient with inherited CARD9 deficiency and ABPA-like presentation due to Aspergillus Terrus. This study paves the way to elucidate immunological mechanisms underlying CARD9 deficiency and aspergillosis.

Of Mycelium and Men: Inherent Human Susceptibility to Fungal Diseases

In medical mycology, the main context of disease is iatrogenic-based disease. However, historically, and occasionally, even today, fungal diseases affect humans with no obvious risk factors, sometimes in a spectacular fashion. The field of “inborn errors of immunity” (IEI) has deduced at least some of these previously enigmatic cases; accordingly, the discovery of single-gene disorders with penetrant clinical effects and their immunologic dissection have provided a framework with which to understand some of the key pathways mediating human susceptibility to mycoses. By extension, they have also enabled the identification of naturally occurring auto-antibodies to cytokines that phenocopy such susceptibility. This review provides a comprehensive update of IEI and autoantibodies that inherently predispose humans to various fungal diseases.

Primary Cutaneous Aspergillosis Due to Aspergillus fumigatus in an Immunocompetent Patient with Diabetes Mellitus After Tattooing: A Case Report and Review of Literature

Background

Aspergillosis is an uncommon fungal infection in which primary cutaneous sites are very rare, and most cases occur in patients with immunocompromised status. Although primary cutaneous aspergillosis is usually encountered in immunocompromised patients, it also occurs in immunocompetent individuals.

Case Presentation

We report a case of primary cutaneous aspergillosis in a 46-year-old immunocompetent woman with diabetes mellitus after tattooing. She presented with erythematous papules, papulopustules and a plaque on the right lower limb of more than two years duration which had failed to respond to antihistamine treatment. Histological examination of a skin biopsy sample showed oval spores in the corneous layer, a slightly thickened epidermis, and infiltrating lymphocytes and neutrophils around the blood vessels in the superficial dermis. Aspergillus fumigatus was isolated and identified in cultures. Clinical and biological examinations did not reveal any systemic localization of aspergillosis, ruling out a hypothesis of blood dissemination. Lesions resolved completely after systemic antifungal treatment with itraconazole.

Conclusion

Clinical lesions of primary cutaneous aspergillosis are nonspecific and usually present as a variety of lesions, including macules, papules, nodules, plaques, purpura, blood blisters, and pustules. The nonspecific features and variety of lesions can lead to misdiagnosis and delayed treatment. Direct microscopy, microbiological culture, and histopathological examination are helpful for diagnosing primary cutaneous aspergillosis. Moreover, the physicians should be aware of the possibility of Aspergillus infection in tattooed cases.

Inborn Errors of Immunity Causing Pediatric Susceptibility to Fungal Diseases

Inborn errors of immunity are a heterogeneous group of genetically determined disorders that compromise the immune system, predisposing patients to infections, autoinflammatory/autoimmunity syndromes, atopy/allergies, lymphoproliferative disorders, and/or malignancies. An emerging manifestation is susceptibility to fungal disease, caused by yeasts or moulds, in a superficial or invasive fashion. In this review, we describe recent advances in the field of inborn errors of immunity associated with increased susceptibility to fungal disease.

CARD9 in host immunity to fungal, bacterial, viral, and parasitic infections: An update

Microbial infection, caused by fungi, bacteria, viruses, and parasites, significantly contributes to the global death burden and health costs. The innate and adaptive immune systems orchestrate a multifaceted signaling response to invading pathogens as the human antimicrobial system. In this process, caspase recruitment domain-containing protein 9 (CARD9) emerges as a critical intermediary adaptor molecule to participate in regulating a series of antimicrobial immune reactions. Previous publications have confirmed that CARD9 plays a crucial role in fungal, bacterial, viral, and parasitic infections. In this study, we aim to provide an update on the recent clinical and basic studies where the mechanism and function of CARD9 have been further studied and understood. In addition, we summarize the latest treatment and prevention strategies based on CARD9 and discuss the current perspectives and future direction of CARD9.

The role of the CBM complex in allergic inflammation and disease

The caspase activation and recruitment domain-coiled-coil (CARD-CC) family of proteins-CARD9, CARD10, CARD11, and CARD14-is collectively expressed across nearly all tissues of the body and is a crucial mediator of immunologic signaling as part of the CARD-B-cell lymphoma/leukemia 10-mucosa-associated lymphoid tissue lymphoma translocation protein 1 (CBM) complex. Dysfunction or dysregulation of CBM proteins has been linked to numerous clinical manifestations known as "CBM-opathies." The CBM-opathy spectrum encompasses diseases ranging from mucocutaneous fungal infections and psoriasis to combined immunodeficiency and lymphoproliferative diseases; however, there is accumulating evidence that the CARD-CC family members also contribute to the pathogenesis and progression of allergic inflammation and allergic diseases. Here, we review the 4 CARD-CC paralogs, as well as B-cell lymphoma/leukemia 10 and mucosa-associated lymphoid tissue lymphoma translocation protein 1, and their individual and collective roles in the pathogenesis and progression of allergic inflammation and 4 major allergic diseases (allergic asthma, atopic dermatitis, food allergy, and allergic rhinitis).

Ten decadal advances in fungal biology leading towards human well-being

Fungi are an understudied resource possessing huge potential for developing products that can greatly improve human well-being. In the current paper, we highlight some important discoveries and developments in applied mycology and interdisciplinary Life Science research. These examples concern recently introduced drugs for the treatment of infections and neurological diseases; application of -OMICS techniques and genetic tools in medical mycology and the regulation of mycotoxin production; as well as some highlights of mushroom cultivaton in Asia. Examples for new diagnostic tools in medical mycology and the exploitation of new candidates for therapeutic drugs, are also given. In addition, two entries illustrating the latest developments in the use of fungi for biodegradation and fungal biomaterial production are provided. Some other areas where there have been and/or will be significant developments are also included. It is our hope that this paper will help realise the importance of fungi as a potential industrial resource and see the next two decades bring forward many new fungal and fungus-derived products.

CARD9 deficiency predisposing chromoblastomycosis: A case report and comparative transcriptome study

CARD9 mutations are known to predispose patients to phaeohyphomycosis caused by different dematiaceous fungal species. In this study, we report for the first time a patient of chromoblastomycosis caused by Phialophora expanda, who harbored CARD9 mutation. Through a series of in vivo and in vitro studies, especially a comparative transcriptome study, we compared this case with our former patient suffering from phaeohyphomycosis caused by Phialophora americana. We showed that P. expanda is prone to forming sclerotic bodies both in vitro and in Card9 knockout mice, and has a stronger immunogenicity than P. americana. These data preliminary demonstrated that besides host defense, fungal specificity also contributed to the clinical phenotype in CARD9 deficient patients with dematiaceous fungal infections.

A Fun-Guide to Innate Immune Responses to Fungal Infections

Immunocompromised individuals are at high risk of developing severe fungal infections with high mortality rates, while fungal pathogens pose little risk to most healthy people. Poor therapeutic outcomes and growing antifungal resistance pose further challenges for treatments. Identifying specific immunomodulatory mechanisms exploited by fungal pathogens is critical for our understanding of fungal diseases and development of new therapies. A gap currently exists between the large body of literature concerning the innate immune response to fungal infections and the potential manipulation of host immune responses to aid clearance of infection. This review considers the innate immune mechanisms the host deploys to prevent fungal infection and how these mechanisms fail in immunocompromised hosts. Three clinically relevant fungal pathogens (Candida albicans, Cryptococcus spp. and Aspergillus spp.) will be explored. This review will also examine potential mechanisms of targeting the host therapeutically to improve outcomes of fungal infection.

CARD9 Signaling, Inflammation, and Diseases

Caspase-recruitment domain 9 (CARD9) protein is expressed in many cells especially in immune cells, and is critically involved in the function of the innate and adaptive immune systems through extensive interactions between CARD9 and other signaling molecules including NF-κB and MAPK. CARD9-mediated signaling plays a central role in regulating inflammatory responses and oxidative stress through the productions of important cytokines and chemokines. Abnormalities of CARD9 and CARD9 signaling or CARD9 mutations or polymorphism are associated with a variety of pathological conditions including infections, inflammation, and autoimmune disorders. This review focuses on the function of CARD9 and CARD9-mediated signaling pathways, as well as interactions with other important signaling molecules in different cell types and the relations to specific disease conditions including inflammatory diseases, infections, tumorigenesis, and cardiovascular pathologies.

Chronic Pulmonary Aspergillosis: Disease Severity Using Image Analysis and Correlation with Systemic Proinflammation and Predictors of Clinical Outcome

(1) Background: The presentation of chronic pulmonary aspergillosis (CPA) ranges from single granuloma to fibrosis in the affected lung. CPA can be divided into five categories according to European Respirology Society (ERS) guidance but is usually assessed by clinical physicians. Computer-based quantitative lung parenchyma analysis in CPA and its correlation with clinical manifestations, systemic inflammation, and angiogenesis have never been investigated. (2) Method: Forty-nine patients with CPA and 36 controls were prospectively enrolled. Pulmonary function tests (forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), and FEV₁/FCV) and biomarkers in the peripheral blood (the chemokines interleukin (IL)-1B, IL-6, IL-10, IL-8, CRP, ESR, MMP1, MMP7, MMP8, TNF-α, calprotectin, SDF-1α, and VEGFA) were measured before antifungal treatment. The disease severity was categorized into mild, moderate, and severe based on chest computed tomography (CT) images. The oxygen demand and overall mortality until the end of the study were recorded. Quantitative parenchyma analysis was performed using the free software 3Dslicer. (3) Results: The results of quantitative parenchyma analysis concorded with the visual severity from the chest CT, oxygen demand, FVC, and FEV₁ in the study subjects. The decrease in kurtosis and skewness of the lung density histograms on CT, increase in high attenuation area (HAA), and reduced lung volume were significantly correlated with increases in the PMN %, CRP, IL-1B, SDF-1α, MMP1, and Calprotectin in peripheral blood in the multivariable regression analysis. TNF-α and IL-1B at study entry and the CPA severity from either a visual method or computer-based evaluation were predictors of long-term mortality. (4) Conclusion: The computer-based parenchyma analysis in CPA agreed with the categorization on a visual basis and was associated with the clinical outcomes, chemokines, and systemic proinflammation profiles.

Case Report: Talaromyces marneffei Infection in a Chinese Child With a Complex Heterozygous CARD9 Mutation

Talaromyces marneffei (TM) infection is rarely seen in clinical practice, and its pathogenesis may be related to deficiency in antifungal immune function. Human caspase recruitment domain-containing protein 9 (CARD9) is a key molecule in fungal immune surveillance. There have been no previous case reports of TM infection in individuals with CARD9 gene mutations. Herein, we report the case of a 7-month-old Chinese boy who was admitted to our hospital with recurring cough and fever with a papular rash. A blood culture produced TM growth, which was confirmed by metagenomic next-generation sequencing. One of the patient’s sisters had died of TM septicaemia at 9 months of age. Whole exome sequencing revealed that the patient had a complex heterozygous CARD9 gene mutation with a c.1118G>C p.R373P variation in exon 8 and a c.610C>T p.R204C variation in exon 4. Based on the culture results, voriconazole antifungal therapy was administered. On the third day of antifungal administration, his temperature dropped to within normal range, the rash gradually subsided, and the enlargement of his lymph nodes, liver, and spleen improved. Two months after discharge, he returned to the hospital for a follow-up examination. His general condition was good, and no specific abnormalities were detected. Oral voriconazole treatment was continued. Unexplained TM infection in HIV-negative individuals warrants investigation for immune deficiencies.

Inherited CARD9 Deficiency in a Child with Invasive Disease Due to Exophiala dermatitidis and Two Older but Asymptomatic Siblings

PURPOSE

Autosomal recessive CARD9 deficiency predisposes patients to invasive fungal disease. Candida and Trichophyton species are major causes of fungal disease in these patients. Other CARD9-deficient patients display invasive diseases caused by other fungi, such as Exophiala spp. The clinical penetrance of CARD9 deficiency regarding fungal disease is surprisingly not complete until adulthood, though the age remains unclear. Moreover, the immunological features of genetically confirmed yet asymptomatic individuals with CARD9 deficiency have not been reported.

METHODS

Identification of CARD9 mutations by gene panel sequencing and characterization of the cellular phenotype by quantitative PCR, immunoblot, luciferase reporter, and cytometric bead array assays were performed.

RESULTS

Gene panel sequencing identified compound heterozygous CARD9 variants, c.1118G>C (p.R373P) and c.586A>G (p.K196E), in a 4-year-old patient with multiple cerebral lesions and systemic lymphadenopathy due to Exophiala dermatitidis. The p.R373P is a known disease-causing variant, whereas the p.K196E is a private variant. Although the patient's siblings, a 10-year-old brother and an 8-year-old sister, were also compound heterozygous, they have been asymptomatic to date. Normal CARD9 mRNA and protein expression were found in the patient's CD14⁺ monocytes. However, these cells exhibited markedly impaired pro-inflammatory cytokine production in response to fungal stimulation. Monocytes from both asymptomatic siblings displayed the same cellular phenotype.

CONCLUSIONS

CARD9 deficiency should be considered in previously healthy patients with invasive Exophiala dermatitidis disease. Asymptomatic relatives of all ages should be tested for CARD9 deficiency. Detecting cellular defects in asymptomatic individuals is useful for diagnosing CARD9 deficiency.