Endemic Fungal Infections in Patients Receiving Tumour Necrosis Factor-α Inhibitor Therapy

Clinical Mycology Today: Emerging Challenges and Opportunities

The Mycoses Study Group Education and Research Consortium is a collective of clinicians, researchers, and educators with the common goal to advance awareness, diagnosis, and management of invasive fungal diseases. Clinical Mycology Today, the Mycoses Study Group Education and Research Consortium's biennial meeting, is dedicated to discussing the most pressing contemporary issues facing the field of clinical mycology, promoting clinical, translational, and basic science collaborations, and mentoring the next generation of clinical mycologists. Here, we review the current opportunities and challenges facing the field of mycology that arose from discussions at the 2022 meeting, with emphasis on novel host risk factors, emerging resistant fungal pathogens, the evolving antifungal pipeline, and critical issues affecting the advancement of mycology research.

Histoplasmosis: A systematic review to inform the World Health Organization of a fungal priority pathogens list

Histoplasmosis, a significant mycosis primarily prevalent in Africa, North and South America, with emerging reports globally, poses notable health challenges, particularly in immunocompromised individuals such as people living with HIV/AIDS and organ transplant recipients. This systematic review, aimed at informing the World Health Organization's Fungal Priority Pathogens List, critically examines literature from 2011 to 2021 using PubMed and Web of Science, focusing on the incidence, mortality, morbidity, antifungal resistance, preventability, and distribution of Histoplasma. We also found a high prevalence (22%-44%) in people living with HIV, with mortality rates ranging from 21% to 53%. Despite limited data, the prevalence of histoplasmosis seems stable, with lower estimates in Europe. Complications such as central nervous system disease, pulmonary issues, and lymphoedema due to granuloma or sclerosis are noted, though their burden remains uncertain. Antifungal susceptibility varies, particularly against fluconazole (MIC: ≥32 mg/l) and caspofungin (MICs: 4-32 mg/l), while resistance to amphotericin B (MIC: 0.125-0.16 mg/l), itraconazole (MICs: 0.004-0.125 mg/l), and voriconazole (MICs: 0.004-0.125 mg/l) remains low. This review identifies critical knowledge gaps, underlining the need for robust, globally representative surveillance systems to better understand and combat this fungal threat.

Granulomas Galore: Concomitant Granulomatous Infections in a Patient With Crohn's Disease

Tumor necrosis factor (TNF)-alpha inhibitors are effective biologics in the treatment of inflammatory bowel disease; however, they increase susceptibility to opportunistic infections. We report a case of a 74-year-old female with Crohn's disease who developed concomitant pulmonary tuberculosis (Mycobacterium tuberculosis [MTB]) and Histoplasmosis capsulatum infection while on adalimumab. Co-infection is rare in patients on TNF-alpha inhibitor therapy, and most cases have been reported in patients with human immunodeficiency virus (HIV). This was a challenging case for diagnosis and treatment due to indistinguishable presenting symptoms of both infections, similar laboratory and radiographical findings, and a clinical course complicated by drug-drug interactions and worsening of symptoms despite therapy.

Coccidioidomycosis Osteoarticular Dissemination

Valley fever or coccidioidomycosis is a pulmonary infection caused by species of Coccidioides fungi that are endemic to California and Arizona. Skeletal coccidioidomycosis accounts for about half of disseminated infections, with the vertebral spine being the preferred site of dissemination. Most cases of skeletal coccidioidomycosis progress to bone destruction or spread to adjacent structures such as joints, tendons, and other soft tissues, causing significant pain and restricting mobility. Manifestations of such cases are usually nonspecific, making diagnosis very challenging, especially in non-endemic areas. The lack of basic knowledge and research data on the mechanisms defining susceptibility to extrapulmonary infection, especially when it involves bones and joints, prompted us to survey available clinical and animal data to establish specific research questions that remain to be investigated. In this review, we explore published literature reviews, case reports, and case series on the dissemination of coccidioidomycosis to bones and/or joints. We highlight key differential features with other conditions and opportunities for mechanistic and basic research studies that can help develop novel diagnostic, prognostic, and treatment strategies.

Pulmonary Histoplasmosis: A Clinical Update

Histoplasma capsulatum, the etiological agent for histoplasmosis, is a dimorphic fungus that grows as a mold in the environment and as a yeast in human tissues. The areas of highest endemicity lie within the Mississippi and Ohio River Valleys of North America and parts of Central and South America. The most common clinical presentations include pulmonary histoplasmosis, which can resemble community-acquired pneumonia, tuberculosis, sarcoidosis, or malignancy; however, certain patients can develop mediastinal involvement or progression to disseminated disease. Understanding the epidemiology, pathology, clinical presentation, and diagnostic testing performance is pivotal for a successful diagnosis. While most immunocompetent patients with mild acute or subacute pulmonary histoplasmosis should receive therapy, all immunocompromised patients and those with chronic pulmonary disease or progressive disseminated disease should also receive therapy. Liposomal amphotericin B is the agent of choice for severe or disseminated disease, and itraconazole is recommended in milder cases or as "step-down" therapy after initial improvement with amphotericin B. In this review, we discuss the current epidemiology, pathology, diagnosis, clinical presentations, and management of pulmonary histoplasmosis.

Surveillance for Coccidioidomycosis, Histoplasmosis, and Blastomycosis - United States, 2019

PROBLEM/CONDITION

Coccidioidomycosis, histoplasmosis, and blastomycosis are underdiagnosed fungal diseases that often mimic bacterial or viral pneumonia and can cause disseminated disease and death. These diseases are caused by inhalation of fungal spores that have distinct geographic niches in the environment (e.g., soil or dust), and distribution is highly susceptible to climate changes such as expanding arid regions for coccidioidomycosis, the northward expansion of histoplasmosis, and areas like New York reporting cases of blastomycosis previously thought to be nonendemic. The national incidence of coccidioidomycosis, histoplasmosis, and blastomycosis is poorly characterized.

REPORTING PERIOD

2019.

DESCRIPTION OF SYSTEM

The National Notifiable Diseases Surveillance System (NNDSS) tracks cases of coccidioidomycosis, a nationally notifiable condition reported to CDC by 26 states and the District of Columbia. Neither histoplasmosis nor blastomycosis is a nationally notifiable condition; however, histoplasmosis is voluntarily reported in 13 states and blastomycosis in five states. Health departments classify cases based on the definitions established by the Council of State and Territorial Epidemiologists.

RESULTS

In 2019, a total of 20,061 confirmed coccidioidomycosis, 1,124 confirmed and probable histoplasmosis, and 240 confirmed and probable blastomycosis cases were reported to CDC. Arizona and California reported 97% of coccidioidomycosis cases, and Minnesota and Wisconsin reported 75% of blastomycosis cases. Illinois reported the greatest percentage (26%) of histoplasmosis cases. All three diseases were more common among males, and the proportion for blastomycosis (70%) was substantially higher than for histoplasmosis (56%) or coccidioidomycosis (52%). Coccidioidomycosis incidence was approximately four times higher for non-Hispanic American Indian or Alaska Native (AI/AN) persons (17.3 per 100,000 population) and almost three times higher for Hispanic or Latino persons (11.2) compared with non-Hispanic White (White) persons (4.1). Histoplasmosis incidence was similar across racial and ethnic categories (range: 0.9-1.3). Blastomycosis incidence was approximately six times as high among AI/AN persons (4.5) and approximately twice as high among non-Hispanic Asian and Native Hawaiian or other Pacific Islander persons (1.6) compared with White persons (0.7). More than one half of histoplasmosis (54%) and blastomycosis (65%) patients were hospitalized, and 5% of histoplasmosis and 9% of blastomycosis patients died. States in which coccidioidomycosis is not known to be endemic had more cases in spring (March, April, and May) than during other seasons, whereas the number of cases peaked slightly in autumn (September, October, and November) for histoplasmosis and in winter (December, January, and February) for blastomycosis.

INTERPRETATION

Coccidioidomycosis, histoplasmosis, and blastomycosis are diseases occurring in geographical niches within the United States. These diseases cause substantial illness, with approximately 20,000 coccidioidomycosis cases reported in 2019. Although substantially fewer histoplasmosis and blastomycosis cases were reported, surveillance was much more limited and underdiagnosis was likely, as evidenced by high hospitalization and death rates. This suggests that persons with milder symptoms might not seek medical evaluation and the symptoms self-resolve or the illnesses are misdiagnosed as other, more common respiratory diseases.

PUBLIC HEALTH ACTION

Improved surveillance is necessary to better characterize coccidioidomycosis severity and to improve detection of histoplasmosis and blastomycosis. These findings might guide improvements in testing practices that enable timely diagnosis and treatment of fungal diseases. Clinicians and health care professionals should consider coccidioidomycosis, histoplasmosis, and blastomycosis in patients with community-acquired pneumonia or other acute infections of the lower respiratory tract who live in or have traveled to areas where the causative fungi are known to be present in the environment. Culturally appropriate tailored educational messages might help improve diagnosis and treatment. Public health response to these three diseases is hindered because information gathered from states' routine surveillance does not include data on populations at risk and sources of exposure. Broader surveillance that includes expansion to other states, and more detail about potential exposures and relevant host factors can describe epidemiologic trends, populations at risk, and disease prevention strategies.

Pathogenesis and virulence of Candida albicans

Candida albicans is a commensal yeast fungus of the human oral, gastrointestinal, and genital mucosal surfaces, and skin. Antibiotic-induced dysbiosis, iatrogenic immunosuppression, and/or medical interventions that impair the integrity of the mucocutaneous barrier and/or perturb protective host defense mechanisms enable C. albicans to become an opportunistic pathogen and cause debilitating mucocutaneous disease and/or life-threatening systemic infections. In this review, we synthesize our current knowledge of the tissue-specific determinants of C. albicans pathogenicity and host immune defense mechanisms.

Pulmonary histoplasmosis diagnosed in a Japanese woman after traveling to central and South America: A case report

Histoplasmosis is a fungal infection caused by Histoplasma capsulatum, and Japan is considered a non-endemic area for histoplasmosis. Most patients diagnosed with histoplasmosis in the past usually have exposure to caves and bat guano with travel history to endemic areas. Therefore, travel history and risk activities should be comprehensively assessed when suspecting histoplasmosis because this important information may be overlooked. Although few, possibilities of indigenous cases have also been suggested. Moreover, it is assumed that the number of travelers and endemic mycoses has decreased with the recent coronavirus disease 2019 epidemic. However, clinicians should carefully consider the differential diagnosis of histoplasmosis for travelers traveling to endemic areas. In this case report, we describe an immunocompetent Japanese woman who developed histoplasmosis due to a history of travel to an endemic country. Our case report suggests that clinicians should not exclude histoplasmosis from the differential diagnosis even in the absence of risk features such as activities or immunodeficiencies during travel.

Reintroduction of immunosuppressive medications in pediatric rheumatology patients with histoplasmosis: a case series

BACKGROUND

Children with rheumatic diseases (cRD) receiving immunosuppressive medications (IM) are at a higher risk for acquiring potentially lethal pathogens, including Histoplasma capsulatum (histoplasmosis), a fungal infection that can lead to prolonged hospitalization, organ damage, and death. Withholding IM during serious infections is recommended yet poses risk of rheumatic disease flares. Conversely, reinitiating IM increases risk for infection recurrence. Tumor necrosis factor alpha inhibitor (TNFai) biologic therapy carries the highest risk for histoplasmosis infection after epidemiological exposure, so other IM are preferred during active histoplasmosis infection. There is limited guidance as to when and how IM can be reinitiated in cRD with histoplasmosis. This case series chronicles resumption of IM, including non-TNFai biologics, disease-modifying anti-rheumatic drugs (DMARDs), and corticosteroids, following histoplasmosis among cRD.

CASE PRESENTATION

We examine clinical characteristics and outcomes of 9 patients with disseminated or pulmonary histoplasmosis and underlying rheumatic disease [juvenile idiopathic arthritis (JIA), childhood-onset systemic lupus erythematosus (cSLE), and mixed connective tissue disease (MCTD)] after reintroduction of IM. All DMARDs and biologics were halted at histoplasmosis diagnosis, except hydroxychloroquine (HCQ), and patients began antifungals. Following IM discontinuation, all patients required systemic or intra-articular steroids during histoplasmosis treatment, with 4/9 showing Cushingoid features. Four patients began new IM regimens [2 abatacept (ABA), 1 HCQ, and 1 methotrexate (MTX)] while still positive for histoplasmosis, with 3/4 (ABA, MTX, HCQ) later clearing their histoplasmosis and 1 (ABA) showing decreasing antigenemia. Collectively, 8/9 patients initiated or continued DMARDs and/or non-TNFai biologic use (5 ABA, 1 tocilizumab, 1 ustekinumab, 3 MTX, 4 HCQ, 1 leflunomide). No fatalities, exacerbations, or recurrences of histoplasmosis occurred during follow-up (median 33 months).

CONCLUSIONS

In our cohort of cRD, histoplasmosis course following reintroduction of non-TNFai IM was favorable, but additional studies are needed to evaluate optimal IM management during acute histoplasmosis and recovery. In this case series, non-TNFai biologic, DMARD, and steroid treatments did not appear to cause histoplasmosis recurrence. Adverse events from corticosteroid use were common. Further research is needed to implement guidelines for optimal use of non-TNFai (like ABA), DMARDs, and corticosteroids in cRD following histoplasmosis presentation.

Blastomycosis

Blastomycosis is the fungal disease caused by thermally dimorphic fungi in the genus Blastomyces, with B dermatitidis complex causing most cases. It is considered hyperendemic in areas adjacent to the Great Lakes and along the St. Lawrence, Mississippi, and Ohio rivers, but definitive geographic distribution of blastomycoses remains obscure. Clinical presentation is variable. Disseminated blastomycosis with extrapulmonary manifestations is more common in immunosuppressed individuals. Culture positivity is required for definitive diagnosis, but compatible histology is often sufficient for presumptive diagnosis and initiation of treatment. Treatment should be provided to all symptomatic cases to prevent progression or recurrence.

Clinical Manifestations and Outcomes in Immunocompetent and Immunocompromised Patients With Blastomycosis

BACKGROUND

Blastomyces is a dimorphic fungus that infects persons with or without underlying immunocompromise. To date, no study has compared the clinical features and outcomes of blastomycosis between immunocompromised and immunocompetent persons.

METHODS

A retrospective study of adult patients with proven blastomycosis from 2004-2016 was conducted at the University of Wisconsin. Epidemiology, clinical features, and outcomes were analyzed among solid-organ transplantation (SOT) recipients, persons with non-SOT immunocompromise (non-SOT IC), and persons with no immunocompromise (NIC).

RESULTS

A total of 106 cases met the inclusion criteria including 74 NIC, 19 SOT, and 13 non-SOT IC (malignancy, HIV/AIDS, idiopathic CD4+ lymphopenia). The majority of patients (61.3%) had at least 1 epidemiologic risk factor for acquisition of Blastomyces. Pneumonia was the most common manifestation in all groups; however, immunocompromised patients had higher rates of acute pulmonary disease (P = .03), more severe infection (P = .007), respiratory failure (P = .010), and increased mortality (P = .02). Receipt of SOT primarily accounted for increased severity, respiratory failure, and mortality in immunosuppressed patients. SOT recipients had an 18-fold higher annual incidence of blastomycosis than the general population. The rate of disseminated blastomycosis was similar among NIC, SOT, and non-SOT IC. Relapse rates were low (5.3-7.7%).

CONCLUSIONS

Immunosuppression had implications regarding the acuity, severity, and respiratory failure. The rate of dissemination was similar across the immunologic spectrum, which is in sharp contrast to other endemic fungi. This suggests that pathogen-related factors have a greater influence on dissemination for blastomycosis than immune defense.

Candida Glabrata Lymphadenitis Following Infliximab Therapy for Inflammatory Bowel Disease in a Patient With Chronic Granulomatous Disease: Case Report and Literature Review

Chronic granulomatous disease (CGD) is an inborn error of immunity caused by inactivating genetic mutations in any one of the components of the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. Phagocytic cell reactive oxygen species generation is impaired in the absence of a functional NADPH oxidase complex. As a result, patients with CGD are at high risk of developing deep-seated infections with certain bacteria and fungi. Additionally, aberrant inflammation and granuloma formation may occur in multiple organs including the bowels, with inflammatory bowel disease seen as a common inflammatory complication of CGD. Traditionally, TNF-α inhibitors are considered effective biological therapies for moderate-to-severe inflammatory bowel disease. While limited case series and reports of patients with CGD have shown improvement in fistula healing with use of TNF-α inhibitors, several patients have developed severe, even fatal, infections with CGD-related pathogens while on TNF-inhibitor therapy. In this case report, we describe an adolescent male with X-linked CGD and steroid-refractory colitis with perirectal fistula and abscesses, who was initiated on treatment with infliximab, a TNF-α inhibitor. Following his first two infliximab doses, the patient developed a Candida glabrata lymphadenitis and associated ulcerating oropharyngeal lesions, requiring hospitalization and therapy with amphotericin B for resolution. We compare our patient's case to prior reports of infliximab use in CGD-related inflammatory bowel disease.

Gastrointestinal Histoplasmosis as an Obstructing Ileocecal Mass

Histoplasmosis is a self-limiting and asymptomatic disease in immunocompetent individuals. Patients in an immunocompromised state are susceptible to disseminated disease. We present a case of a 60-year-old male with a history of psoriatic and rheumatoid arthritis treated with a tumor necrosis factor inhibitor (adalimumab), who presented with abdominal pain and was found to have gastrointestinal histoplasmosis as an obstructing ileocecal mass. Although gastrointestinal involvement is common in disseminating disease, symptomatic involvement is rare. This case presentation has implications in rheumatological patients on biologic medications.

Granulomatous lung disease: clinical aspects

INTRODUCTION

Granulomatous lung diseases (GLD) are heterogeneous group of diseases that can be broadly categorized as infectious or noninfectious. This distinction is extremely important, as the misdiagnosis of a GLD can have serious consequences. In this manuscript, we describe the clinical manifestations, histopathology, and diagnostic approach to GLD. We propose an algorithm to distinguish infectious from noninfectious GLD.

AREAS COVERED

We have searched PubMed and Medline database from 1950 to December 2019, using multiple keywords as described below. Major GLDs covered include those caused by mycobacteria and fungi, sarcoidosis, hypersensitivity pneumonitis, and vasculidities.

EXPERT OPINION

The cause of infectious GLD is usually identified through microbiological culture and molecular techniques. Most noninfectious GLD are diagnosed by clinical and laboratory criteria, often with exclusion of infectious pathogens. Further understanding of the immunopathogenesis of the granulomatous response may allow improved diagnosis and treatment of GLD.

Fungal infection risks associated with the use of cytokine antagonists and immune checkpoint inhibitors

IMPACT STATEMENT

The risk of opportunistic infections due to fungi is relatively less well addressed in patients receiving biologic agents, compared with other opportunistic bacterial and viral infections. There is a lack of consensus guideline on the screening, prophylaxis, and management of fungal infection in patients anticipated to receive or actively receiving biologic therapy. In addition, invasive mycosis in immunocompromised patients is associated with high mortality and morbidity. This review highlighted the risk of fungal infection in patients receiving cytokine antagonists and immune checkpoint inhibitors, two big categories of biologic agents that are widely used in the treatment of various autoimmune and malignant conditions, often in combination with other immunomodulatory or immunosuppressive agents but also as standalone therapy. The adverse outcomes of opportunistic fungal infection in these patients can be reduced by heightened awareness, active case finding, and prompt treatment.

First report of paracoccidioidomycosis reactivation as a complication of immunosuppressive therapy for acute severe colitis in a caving enthusiast

Treatment for ulcerative colitis often requires the administration of immunosuppressive therapy. Shortly after rescue therapy with infliximab for acute severe colitis, a patient who was also taking corticosteroids, azathioprine and adalimumab became rapidly unwell with atypical pneumonia, which did not respond to conventional antimicrobials. Re-examining the travel history revealed a prior caving trip to Costa Rica. Dimorphic fungal serology was thus tested and a diagnosis of paracoccidioidomycosis was made. After a lengthy intensive care unit admission, the patient made a recovery after the administration of appropriate antifungal therapy and was discharged home on long-term oral antifungals.

Fungal Infections Potentiated by Biologics

Biologic therapies including monoclonal antibodies, tyrosine kinase inhibitors, and other agents represent a notable expansion in the pharmacotherapy armamentarium in treatment of a variety of diseases. Many of these therapies possess direct or indirect immunosuppressive and immunomodulatory effects, which have been associated with bacterial, viral, and fungal opportunistic infections. Careful screening of baseline risk factors before initiation, targeted preventive measures, and vigilant monitoring while on active biologic therapy mitigate these risks as use of biologics becomes more commonplace. This review compiles reported evidence of fungal infections associated with these agents with a focus on the tumor necrosis factor-α inhibitor class.

HIV-Associated Histoplasmosis: Current Perspectives

Histoplasmosis is an endemic mycosis caused by Histoplasma capsulatum. Infection develops by inhalation of microconidia from environmental sites inhabited by birds and bats. Disseminated disease is the usual presentation due to impaired cellular immunity. Common clinical manifestations include fever, fatigue, malaise, anorexia, weight loss, and respiratory symptoms. Histoplasma antigen detection is the most sensitive method for diagnosis. The sensitivity of the MVista^® Quantitative Histoplasma antigen enzyme immunoassay is 95-100% in urine, over 90% in serum and bronchoalveolar lavage (BAL) antigen and 78% in cerebral spinal fluid (CSF). A proven diagnosis can be established by culture or pathology with sensitivities between 70% and 80%. The sensitivity of antibody detection by immunodiffusion or complement fixation was between 60% and 70%. Diagnosis using molecular methods has not been adequately validated for implementation and FDA cleared assays are unavailable. Liposomal amphotericin B should be used for 1-2 weeks followed by itraconazole for at least one year until CD4 counts are above 150 cells/mm3, HIV viral load is below 400 copies/mL and Histoplasma urine antigen is negative. Serum itraconazole level should be monitored to avoid drug toxicity. Antigen should be measured periodically to establish that treatment is effective and to assist in identifying relapse. The incidence of immune reconstitution inflammatory syndrome is low but it must be considered in patients who are thought to be failing antifungal treatment as it does not respond to changing antifungal agents but rather to initiation of corticosteroid therapy. In this review, we discuss pathogenesis, clinical manifestations, diagnosis and treatment based on personal experience and relevant publications.

Advances in Understanding Human Genetic Variations That Influence Innate Immunity to Fungi

Fungi are ubiquitous. Yet, despite our frequent exposure to commensal fungi of the normal mammalian microbiota and environmental fungi, serious, systemic fungal infections are rare in the general population. Few, if any, fungi are obligate pathogens that rely on infection of mammalian hosts to complete their lifecycle; however, many fungal species are able to cause disease under select conditions. The distinction between fungal saprophyte, commensal, and pathogen is artificial and heavily determined by the ability of an individual host's immune system to limit infection. Dramatic examples of commensal fungi acting as opportunistic pathogens are seen in hosts that are immune compromised due to congenital or acquired immune deficiency. Genetic variants that lead to immunological susceptibility to fungi have long been sought and recognized. Decreased myeloperoxidase activity in neutrophils was first reported as a mechanism for susceptibility to Candida infection in 1969. The ability to detect genetic variants and mutations that lead to rare or subtle susceptibilities has improved with techniques such as single nucleotide polymorphism (SNP) microarrays, whole exome sequencing (WES), and whole genome sequencing (WGS). Still, these approaches have been limited by logistical considerations and cost, and they have been applied primarily to Mendelian impairments in anti-fungal responses. For example, loss-of-function mutations in CARD9 were discovered by studying an extended family with a history of fungal infection. While discovery of such mutations furthers the understanding of human antifungal immunity, major Mendelian susceptibility loci are unlikely to explain genetic disparities in the rate or severity of fungal infection on the population level. Recent work using unbiased techniques has revealed, for example, polygenic mechanisms contributing to candidiasis. Understanding the genetic underpinnings of susceptibility to fungal infections will be a powerful tool in the age of personalized medicine. Future application of this knowledge may enable targeted health interventions for susceptible individuals, and guide clinical decision making based on a patient's individual susceptibility profile.

Fungal infections following treatment with monoclonal antibodies and other immunomodulatory therapies

Tumor necrosis factor (TNF) is a proinflammatory cytokine involved in a wide range of important physiologic processes and has a pathologic role in some diseases. TNF antagonists (infliximab, adalimumab, etanercept) are effective in treating inflammatory conditions. Antilymphocyte biological agents (rituximab, alemtuzumab), integrin antagonists (natalizumab, etrolizumab and vedolizumab), interleukin (IL)-17A blockers (secukinumab, ixekizumab) and IL-2 antagonists (daclizumab, basiliximab) are widely used after transplantation and for gastroenterological, rheumatological, dermatological, neurological and hematological disorders. Given the putative role of these host defense elements against bacterial, viral and fungal agents, the risk of infection during a treatment with these antagonists is a concern. Fungal infections, both opportunistic and endemic, have been associated with these biological therapies, but the causative relationship is unclear, especially among patients with poor control of their underlying disease or who are undergoing steroid therapy. Potential recipients of these drugs should be screened for latent endemic fungal infections. Cotrimoxazole prophylaxis could be useful for preventing Pneumocystis jirovecii infection in patients over 65 years of age who are taking TNF antagonists, antilymphocyte biological agents or who have lymphopenia and are undergoing concomitant steroid therapy. As with other immunosuppressant drugs, TNF antagonists and antilymphocyte antibodies should be discontinued for patients with active infectious disease.

How Environmental Fungi Cause a Range of Clinical Outcomes in Susceptible Hosts

Environmental fungi are globally ubiquitous and human exposure is near universal. However, relatively few fungal species are capable of infecting humans, and among fungi, few exposure events lead to severe systemic infections. Systemic infections have mortality rates of up to 90%, cost the US healthcare system $7.2 billion annually, and are typically associated with immunocompromised patients. Despite this reputation, exposure to environmental fungi results in a range of outcomes, from asymptomatic latent infections to severe systemic infection. Here we discuss different exposure outcomes for five major fungal pathogens: Aspergillus, Blastomyces, Coccidioides, Cryptococcus, and Histoplasma species. These fungi include a mold, a budding yeast, and thermal dimorphic fungi. All of these species must adapt to dramatically changing environments over the course of disease. These dynamic environments include the human lung, which is the first exposure site for these organisms. Fungi must defend themselves against host immune cells while germinating and growing, which risks further exposing microbe-associated molecular patterns to the host. We discuss immune evasion strategies during early infection, from disruption of host immune cells to major changes in fungal cell morphology.

Central Nervous System Infection with Histoplasma capsulatum

Histoplasmosis is an endemic fungal infection that may affect both immune compromised and non-immune compromised individuals. It is now recognized that the geographic range of this organism is larger than previously understood, placing more people at risk. Infection with Histoplasma capsulatum may occur after inhalation of conidia that are aerosolized from the filamentous form of the organism in the environment. Clinical syndromes typically associated with histoplasmosis include acute or chronic pneumonia, chronic cavitary pulmonary infection, or mediastinal fibrosis or lymphadenitis. Disseminated infection can also occur, in which multiple organ systems are affected. In up to 10% of cases, infection of the central nervous system (CNS) with histoplasmosis may occur with or without disseminated infection. In this review, we discuss challenges related to the diagnosis of CNS histoplasmosis and appropriate treatment strategies that can lead to successful outcomes.

Central Nervous System Infection with Other Endemic Mycoses: Rare Manifestation of Blastomycosis, Paracoccidioidomycosis, Talaromycosis, and Sporotrichosis

The central nervous system (CNS) is not a major organ involved with infections caused by the endemic mycoses, with the possible exception of meningitis caused by Coccidioides species. When CNS infection does occur, the manifestations vary among the different endemic mycoses; mass-like lesions or diffuse meningeal involvement can occur, and isolated chronic meningitis, as well as widely disseminated acute infection that includes the CNS, are described. This review includes CNS infection caused by Blastomyces dermatitidis, Paracoccidioides brasiliensis, Talaromyces marneffei, and the Sporothrix species complex. The latter is not geographically restricted, in contrast to the classic endemic mycoses, but it is similar in that it is a dimorphic fungus. CNS infection with B. dermatitidis can present as isolated chronic meningitis or a space-occupying lesion usually in immunocompetent hosts, or as one manifestation of widespread disseminated infection in patients who are immunosuppressed. P. brasiliensis more frequently causes mass-like intracerebral lesions than meningitis, and most often CNS disease is part of disseminated infection found primarily in older patients with the chronic form of paracoccidioidomycosis. T. marneffei is the least likely of the endemic mycoses to cause CNS infection. Almost all reported cases have been in patients with advanced HIV infection and almost all have had widespread disseminated infection. Sporotrichosis is known to cause isolated chronic meningitis, primarily in immunocompetent individuals who do not have Sporothrix involvement of other organs. In contrast, CNS infection in patients with advanced HIV infection occurs as part of widespread disseminated infection.

Risks associated with use of TNF inhibitors in children with rheumatic diseases

Introduction: Tumor necrosis factor alpha (TNF-α) is a pro-inflammatory cytokine involved in the pathogenesis of many inflammatory diseases. Several drugs blocking TNF-α are employed in clinical practice in pediatrics. Given their action on the immune system, TNF-α inhibitors have raised concerns on their safety profile since their introduction. A broad spectrum of side effects related to TNF inhibition has been reported: immunogenicity, infectious diseases, malignancies, and others. Areas covered: In order to assess the risk related to the use of anti-TNF-α agents in children with rheumatic diseases we analyzed data obtained from retrospective and prospective safety studies, case reports and case series, and controlled trials. Expert commentary: Anti-TNF-α agents have shown a remarkably good safety profile in the pediatric population so far. However, there are lots of questions to be answered and maintaining active surveillance on these drugs is necessary in order to not overlook any possible unexpected adverse effects.

Pulmonary paracoccidioidomycosis: a case report of reactivation in a patient receiving biological therapy

Paracoccidioidomycosis is an endemic disease in Latin America that is rarely associated with immunosuppression and biological therapy. Herein, we report for the first time a case of pulmonary paracoccidioidomycosis reactivation after infliximab treatment. A 47-year-old man from Brazil received infliximab to treat psoriatic spondyloarthropathy and presented with cough, dyspnea, weight loss, and fever. Chest computed tomography revealed a pulmonary nodule and biopsy confirmed paracoccidioidomycosis. Treatment with sulfamethoxazole and trimethoprim was initiated for fungal infection and infliximab was reintroduced two months later. Considering his clinical improvement and favorable radiologic evolution, antifungal therapy was discontinued after 29 months.

Case Report: Histoplasmosis: First Autochthonous Case from Israel

We present an autochthonous Histoplasma infection in Israel. The patient presented with hoarseness and weight loss. Pathology findings and molecular tests confirmed the diagnosis, and the patient responded to antifungal therapy. Because the patient had an atypical presentation of histoplasmosis, it is likely that other more typical cases have gone unreported. To our knowledge, no other cases have been previously reported from Israel or the Middle East region.

Cave diving for a diagnosis: Disseminated histoplasmosis in the immunocompromised

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Tumor necrosis factor (TNF) inhibitors are associated with risks of invasive infections.

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Disseminated histoplasmosis can be easily mistaken for a pneumonia.

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Confounding comorbidities and travel-associated risk factors may delay diagnoses.

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Liposomal amphotericin b, may or may not have altered the course of this patient’s illness.

Tumor necrosis factor (TNF) inhibitors are widely used in the treatment of inflammatory conditions and are associated with risks of invasive infections. We present a diagnostically challenging patient with unique comorbidities and travel history. A 53-year-old man with a history of polysubstance abuse and psoriasis on adalimumab presented to our hospital directly from the airport with fever, dyspnea, and cough. He had been living in Costa Rica and engaged in many outdoor activities. Within 6 h and a limited history, he was intubated; vasopressors and antimicrobials were promptly administered. An extensive infectious disease investigation was undertaken, considering potential travel-related exposures and his immunosuppressive state. However, multi-organ failure with worsening disseminated intravascular coagulation ensued, and within four days of admission, the patient passed away. Five days after his death, the urine Histoplasma antigen resulted positive. Disseminated histoplasmosis should be suspected in a patient on anti-TNF therapy, with a severe febrile illness and pneumonia refractory to antibacterial therapy. A high index of suspicion is necessary to make the diagnosis and initiate prompt treatment.

Central Nervous System Infections Associated with Immunosuppressive Therapy for Rheumatic Disease

Patients on immunosuppressive therapy for rheumatic diseases are at increased risk of infection. Although infections of the central nervous system (CNS) are less common compared with other sites, patients on broadly immunosuppressive and biologic immunomodulatory agents may be susceptible to more severe, disseminated forms of infection, including of the CNS. Certain key principles regarding infection risk apply across immunosuppressive therapies, including increased risk with higher doses and longer duration of therapy and with combination therapy. Providers should be aware of the CNS infection risk related to immunosuppressant use to help guide best practices for screening and prophylaxis.

Clinical Manifestations and Treatment of Blastomycosis

The causal agents of blastomycosis, Blastomyces dermatitidis and Blastomyces gilchristii, belong to a group of thermally dimorphic fungi that can infect healthy and immunocompromised individuals. Following inhalation of mycelial fragments and spores into the lungs, Blastomyces spp convert into pathogenic yeast and evade host immune defenses to cause pneumonia and disseminated disease. The clinical spectrum of pulmonary blastomycosis is diverse. The diagnosis of blastomycosis requires a high degree of clinical suspicion and involves culture-based and non-culture-based fungal diagnostic tests. The site and severity of infection, and the presence of underlying immunosuppression or pregnancy, influence the selection of antifungal therapy.

Blastomycosis

Blastomycosis is an endemic fungal infection due to Blastomyces dermatitidis that most commonly causes pneumonia; but the organism can disseminate to any organ system, most commonly the skin, bones/joints, and genitourinary tract. Both immunocompetent and immunocompromised persons can be infected, but more severe disease occurs in the immunocompromised. Blastomycosis can be diagnosed by culture, direct visualization of the yeast in affected tissue, and/or antigen testing. Treatment course and duration depend on severity of illness. For mild to moderate pulmonary disease the treatment is itraconazole. For severe blastomycosis, lipid formulation amphotericin B is given, followed by step-down therapy with itraconazole.

TNF biology, pathogenic mechanisms and emerging therapeutic strategies

TNF is a pleiotropic cytokine with important functions in homeostasis and disease pathogenesis. Recent discoveries have provided insights into TNF biology that introduce new concepts for the development of therapeutics for TNF-mediated diseases. The model of TNF receptor signalling has been extended to include linear ubiquitination and the formation of distinct signalling complexes that are linked with different functional outcomes, such as inflammation, apoptosis and necroptosis. Our understanding of TNF-induced gene expression has been enriched by the discovery of epigenetic mechanisms and concepts related to cellular priming, tolerization and induction of 'short-term transcriptional memory'. Identification of distinct homeostatic or pathogenic TNF-induced signalling pathways has introduced the concept of selectively inhibiting the deleterious effects of TNF while preserving its homeostatic bioactivities for therapeutic purposes. In this Review, we present molecular mechanisms underlying the roles of TNF in homeostasis and inflammatory disease pathogenesis, and discuss novel strategies to advance therapeutic paradigms for the treatment of TNF-mediated diseases.

Atypical Cutaneous Blastomycosis in a Child With Juvenile Idiopathic Arthritis on Infliximab

Blastomyces dermatitidis is a dimorphic fungus endemic to much of North America, particularly the soils of the midwestern and southeastern United States. Human infection typically occurs through inhalation of airborne conidia, which can be followed occasionally by dissemination to the skin, bone, genitourinary system, and central nervous system. A hallmark of the pathogen is that it can cause disease in both immunocompetent and immunosuppressed populations. Blastomycosis is rare in pediatric patients, with cutaneous manifestations occurring even less frequently. Here, we report the case of a 9-year-old boy on iatrogenic immunosuppression with infliximab and methotrexate for juvenile idiopathic arthritis who presented with a nonhealing, indurated plaque of his right ear with significant superficial yellow crusting in the absence of constitutional symptoms. After failing a prolonged course of topical and oral antibiotic therapy, biopsy and tissue culture revealed Blastomyces dermatitidis infection. The area cleared after treatment with oral fluconazole and withdrawal of infliximab. To our knowledge, this is the first report of a pediatric patient developing an infection with B dermatitidis after initiation of therapy with a tumor necrosis factor-α inhibitor. This case also highlights an unusual morphology of cutaneous blastomycosis in an iatrogenically immunosuppressed child.

MyD88-dependent signaling drives host survival and early cytokine production during Histoplasma capsulatum infection

The ability of the innate immune system to trigger an adaptive T cell response is critical to resolution of infection with the fungal pathogen Histoplasma capsulatum. However, the signaling pathways and cell types involved in the recognition of and response to this respiratory pathogen remain poorly defined. Here, we show that MyD88, an adaptor protein vital to multiple innate immune pathways, is critically required for the host response to Histoplasma. MyD88-deficient (MyD88-/-) mice are unable to control the fungal burden and are more sensitive to Histoplasma infection than wild-type, Dectin-1-/-, or interleukin 1 receptor-deficient (IL-1R-/-) mice. We found that MyD88 is necessary for the production of key early inflammatory cytokines and the subsequent recruitment of inflammatory monocytes to the lung. In both our in vitro and ex vivo analyses, MyD88 was intrinsically required in dendritic cells and alveolar macrophages for initial cytokine production. Additionally, MyD88-deficient bone marrow-derived dendritic cells fail to efficiently control fungal growth when cocultured with primed splenic T cells. Surprisingly, mice that lack MyD88 only in dendritic cells and alveolar macrophages are competent for early cytokine production and normal survival, indicating the presence of compensatory and redundant MyD88 signaling in other cell types during infection. Ultimately, global MyD88 deficiency prevents proper T cell activation and gamma interferon (IFN-γ) production, which are critical for infection resolution. Collectively, this work reveals a central role for MyD88 in coordinating the innate and adaptive immune responses to infection with this ubiquitous fungal pathogen of humans.

Thermally Dimorphic Human Fungal Pathogens--Polyphyletic Pathogens with a Convergent Pathogenicity Trait

Fungi are adept at changing their cell shape and developmental program in response to signals in their surroundings. Here we focus on a group of evolutionarily related fungal pathogens of humans known as the thermally dimorphic fungi. These organisms grow in a hyphal form in the environment but shift their morphology drastically within a mammalian host. Temperature is one of the main host signals that initiates their conversion to the "host" form and is sufficient in the laboratory to trigger establishment of this host-adapted developmental program. Here we discuss the major human pathogens in this group, which are Blastomyces dermatiditis, Coccidioides immitis/posadasii, Histoplasma capsulatum, Paracoccidioides brasiliensis/lutzii, Sporothrix schenckii, and Talaromyces marneffei (formerly known as Penicillium marneffei). The majority of these organisms are primary pathogens, with the ability to cause disease in healthy humans who encounter them in endemic areas.

Recent advances in our understanding of the environmental, epidemiological, immunological, and clinical dimensions of coccidioidomycosis

Coccidioidomycosis is the endemic mycosis caused by the fungal pathogens Coccidioides immitis and C. posadasii. This review is a summary of the recent advances that have been made in the understanding of this pathogen, including its mycology, genetics, and niche in the environment. Updates on the epidemiology of the organism emphasize that it is a continuing, significant problem in areas of endemicity. For a variety of reasons, the number of reported coccidioidal infections has increased dramatically over the past decade. While continual improvements in the fields of organ transplantation and management of autoimmune disorders and patients with HIV have led to dilemmas with concurrent infection with coccidioidomycosis, they have also led to advances in the understanding of the human immune response to infection. There have been some advances in therapeutics with the increased use of newer azoles. Lastly, there is an overview of the ongoing search for a preventative vaccine.

Infectious and malignant complications of TNF inhibitor therapy in IBD

Tumor necrosis factor (TNF) inhibitors are being increasingly utilized in the management of inflammatory bowel disease (IBD). Although the benefits associated with TNF inhibitor therapy are undeniable, concerns have been raised about the associated risk of infectious and malignant complications. In this narrative review, we will present the evidence from studies that have evaluated the association of TNF inhibitors and both overall and specific infections and malignancy. Overall, although TNF inhibitors may increase the risk of tuberculosis, varicella, and other opportunistic infections, there is little evidence suggesting that anti-TNF agents specifically raise the overall risk of serious infections. Similarly, there is little evidence that TNF antagonists raise the risk of developing malignancy over and above the risks from concomitant therapies and the underlying disease process. However, the risk of nonmelanoma skin cancers may be increased and that is further enhanced by use of combination TNF inhibitor and thiopurine therapy. The risk of non-Hodgkin's lymphoma is statistically increased among combination therapy users. The absolute risk remains a very small but feared risk. It is difficult to fully quantify the risk of these cancers among users of TNF inhibitor therapy in the absence of concurrent thiopurine therapy. We recommend that clinicians remain mindful about the potential risks of infectious and malignant complications in their IBD patients who are using TNF inhibitors, but that further research is required to better study these risks over the long-term course of therapy.

Endemic mycoses in immunocompromised hosts

Endemic mycoses remain a significant cause of morbidity and mortality among immunocompromised patients. As the number of immunosuppressed individuals increases worldwide, the incidence of endemic mycoses is also expected to rise. In immunocompromised patients, endemic mycoses can present in atypical fashion, cause more severe and/or disseminated disease, and result in higher mortality. Despite several noteworthy advances over the past decade, significant challenges remain with regard to the prevention, diagnosis, and therapy of endemic mycoses in immunocompromised hosts. This review highlights important developments related to the epidemiology, diagnosis, treatment, and prevention of commonly encountered endemic mycoses. We also discuss emerging topics, knowledge gaps, and areas of future research.

Interferon alpha treatment of patients with impaired interferon gamma signaling

Patients with deficiency in the interferon gamma receptor (IFN-γR) are unable to respond properly to IFN-γ and develop severe infections with nontuberculous mycobacteria (NTM). IFN-γ and IFN-α are known to signal through STAT1 and activate many downstream effector genes in common. Therefore, we added IFN-α for treatment of patients with disseminated mycobacterial disease in an effort to complement their IFN-γ signaling defect. We treated four patients with IFN-γR deficiency with adjunctive IFN-α therapy in addition to best available antimicrobial therapy, with or without IFN-γ, depending on the defect. During IFN-α treatment, ex vivo induction of IFN target genes was detected. In addition, IFN-α driven gene expression in patients' cells and mycobacteria induced cytokine response were observed in vitro. Clinical responses varied in these patients. IFN-α therapy was associated with either improvement or stabilization of disease. In no case was disease exacerbated. In patients with profoundly impaired IFN-γ signaling who have refractory infections, IFN-α may have adjunctive anti-mycobacterial effects.

Clinical use of anti-TNF therapy and increased risk of infections

Biologics such as antitumor necrosis factor (anti-TNF) drugs have emerged as important agents in the treatment of many chronic inflammatory diseases, especially in cases refractory to conventional treatment modalities. However, opportunistic infections have become a major safety concern in patients on anti-TNF therapy, and physicians who utilize these agents must understand the increased risks of infection. A literature review of the published data on the risk of bacterial, viral, fungal, and parasitic infections associated with anti-TNF therapy was performed and the clinical presentation, diagnostic tests, management, and prevention of opportunistic infections in patients receiving anti-TNF therapy were reviewed. Awareness of the therapeutic potential and associated adverse events is necessary for maximizing therapeutic benefits while minimizing adverse effects from anti-TNF treatments. Patients should be adequately vaccinated when possible and closely monitored for early signs of infection. When serious infections occur, withdrawal of anti-TNF therapy may be necessary until the infection has been identified and properly treated.