Batf3-dependent orchestration of the robust Th1 responses and fungal control during cryptococcal infection, the role of cDC1

While type I conventional dendritic cells (cDC1s) are vital for generating adaptive immunity against intracellular pathogens and tumors, their role in defense against fungal pathogen Cryptococcus neoformans remains unclear. We investigated the role of the cDC1 subset in a fungus-restricting mouse model of cryptococcal infection. The cDC1 subset displayed a unique transcriptional signature with highly upregulated T-cell recruitment, polarization, and activation pathways compared to other DC subsets. Using Batf3-/- mice, which lack the cDC1 population, our results support that Batf3-dependent cDC1s are pivotal for the development of the effective immune response against cryptococcal infection, particularly within the lung and brain. Deficiency in Batf3 cDC1 led to diminished CD4 accumulation and decreased IFNγ production across multiple organs, supporting that cDC1s are a major driver of potent Th1 responses during cryptococcal infection. Consistently, mice lacking Batf3-cDC1 demonstrated markedly diminished fungicidal activity and weaker containment of the fungal pathogen. In conclusion, Batf3-dependent cDC1 can function as a linchpin in mounting Th1 response, ensuring effective fungal control during cryptococcal infection. Harnessing cDC1 pathways may present a promising strategy for interventions against this pathogen.IMPORTANCECryptococcus neoformans causes severe meningoencephalitis, accounting for an estimated 200,000 deaths each year. Central to mounting an effective defense against these infections is T-cell-mediated immunity, which is orchestrated by dendritic cells (DCs). The knowledge about the role of specific DC subsets in shaping anti-cryptococcal immunity is limited. Here, we demonstrate that Batf3 cDC1s are important drivers of protective Th1 CD4 T-cell responses required for clearance of cryptococcal infection. Deficiency of Batf3 cDC1 in the infected mice leads to significantly reduced Th1 response and exacerbated fungal growth to the point where depleting the remaining CD4 T cells no longer affects fungal burden. Unveiling this pivotal role of cDC1 in antifungal defense is likely to be important for the development of vaccines and therapies against life-threatening fungal pathogens.

Disseminated Cryptococcosis Is a Common Finding among Human Immunodeficiency Virus-Infected Patients with Suspected Sepsis and Is Associated with Higher Mortality Rates

Cryptococcosis is the leading cause of death among people with HIV in Sub-Saharan Africa. The lack of optimum diagnoses and medications significantly impair the management of the disease. We investigated the burden of cryptococcosis and related mortality among people with HIV and suspected sepsis in Ethiopia. We conducted a prospective study at (1) Adama Hospital Medical College and (2) Asella Referral and Teaching Hospital from September 2019 to November 2020. We enrolled adult, HIV-infected patients presenting with suspected sepsis and assessed their 28-day survival rates. We performed blood cultures and cryptococcal antigen (CrAg) testing. In total, 82 participants were enrolled with a median age of 35 years, and 61% were female. Overall, eleven (13%) had positive CrAg tests, of which five grew Cryptococcus in blood cultures. Despite high-dose fluconazole (1200 mg/d) monotherapy being given to those with positive CrAg tests, the 28-day mortality was 64% (7/11), with mortality being significantly higher than among the CrAg-negative patients (9% (6/71); p < 0.001). Cryptococcosis was the leading cause of mortality among HIV-infected sepsis patients in this Ethiopian cohort. The CrAg screening of HIV-infected patients attending an emergency department can minimize the number of missed cryptococcosis cases irrespective of the CD4 T cell count and viral load. These findings warrant the need for a bundle approach for the diagnosis of HIV-infected persons presenting with sepsis in low- and middle-income countries.

Mycotic Pseudotumor of the Breast Secondary to Cryptococcal Infection: Report of Three Rare Cases and Literature Review

Breast masses in clinical practice are often investigated primarily for neoplastic conditions. Breast fungal infections are unusual, and few cases have been reported in the literature. The differential diagnosis for a breast mass should not be limited to neoplastic conditions as there are treatment implications. The correct diagnosis is associated with reduced and unwanted cases of surgical intervention. We describe 3 cases of cryptococcal infection of the breast that clinically masqueraded as breast malignancies.

Characterization of an immunogenic cellulase secreted by Cryptococcus pathogens

Members of the C. neoformans/C. gattiii species complex are an important cause of serious humans infections, including meningoencephalitis. We describe here a 45 kDa extracellular cellulase purified from culture supernatants of C. neoformans var. neoformans. The N-terminal sequence obtained from the purified protein was used to isolate a clone containing the full-length coding sequence from a C. neoformans var. neoformans (strain B-3501A) cDNA library. Bioinformatics analysis indicated that this gene is present, with variable homology, in all sequenced genomes of the C. neoformans/C. gattii species complex. The cDNA clone was used to produce a recombinant 45 kDa protein in E. coli that displayed the ability to convert carboxymethyl cellulose and was therefore designated as NG-Case (standing for Neoformans Gattii Cellulase). To explore its potential use as a vaccine candidate, the recombinant protein was used to immunize mice and was found capable of inducing T helper type 1 responses and delayed-type hypersensitivity reactions, but not immune protection against a highly virulent C. neoformans var grubii strain. These data may be useful to better understand the mechanisms underlying the ability C. neoformans/C. gattii to colonize plant habitats and to interact with the human host during infection.

Clinical characteristics and evaluation of the incidence of cryptococcosis in Finland 2004-2018

BACKGROUND

Cryptococcosis is one of the major causes of mortality among HIV patients worldwide. Though most often associated with late stage HIV infection/AIDS, a significant number of cases occur in other immunocompromised patients such as solid organ transplant recipients and patients with hematological malignancies. Immunocompromised patients are a heterogeneous group and their number increases constantly. Since little is known about the incidence and the clinical features of cryptococcosis in Northern Europe, our aim was to investigate the clinical characteristics of cryptococcosis patients in Finland.

METHODS

We retrospectively reviewed the laboratory confirmed cryptococcosis cases in Finland during 2004-2018. Only those who were treated for cryptococcosis were included in the study. Initial laboratory findings and medical records were also collected.

RESULTS

A total of 22 patients with cryptococcosis were included in our study. The annual incidence of cryptococcosis was 0.03 cases per 100,000 population. Ten patients were HIV-positive and 12 out of 22 were HIV-negative. Hematological malignancy was the most common underlying condition among HIV-negative patients.

CONCLUSIONS

To our knowledge, this is the first study of the clinical presentation and incidence of cryptococcosis in Finland. We demonstrate that invasive cryptococcal infection occurs not only in HIV/AIDS patients or otherwise immunocompromised patients but also in immunocompetent individuals. Even though cryptococcosis is extremely rare in Finland, its recognition is important since the prognosis depends on rapid diagnostics and early antifungal therapy.

Coexistent pulmonary cryptococcal infection and pulmonary sarcoidosis: a case report and literature review

Cryptococcus is an encapsulated, yeast-like fungus commonly responsible for infections in individuals with impaired T cell-mediated immune responses, including those with acquired immune deficiency syndrome or taking immunosuppressive agents such as steroids or cyclosporine. However, pulmonary fungal infection is rare in patients with untreated sarcoidosis. We report a case of coexistent pulmonary cryptococcal infection in a 43-year-old man with pulmonary sarcoidosis in North-western China. The patient was diagnosed with sarcoidosis via right anterior mediastinal lymph node biopsy and lung biopsy by bronchoscopy. He was treated with oral prednisone 25 mg/day and achieved complete remission of all symptoms. However, repeat chest computed tomography examination revealed enlarged nodules in the left lower lobe, but decreased bilateral diffuse small nodules in the lungs. Computed tomography-guided percutaneous lung puncture biopsy revealed cryptococcal infection. This case highlights the need to consider fungal infection in patients with sarcoidosis at initial presentation, irrespective of their use of immunosuppressive medication.

CircRNA-1806 Decreases T Cell Apoptosis and Prolongs Survival of Mice After Cryptococcal Infection by Sponging miRNA-126

CircRNAs are a recently well-known regulator that mediates a variety of biological processes. Cryptococcus neoformans is an environmental fungal pathogen that can cause fatal cryptococcal meningitis in immunocompromised individuals. However, the involvement of circRNA in cryptococcal infection remains unclear. In this study, high-throughput microarray was performed to identify the circRNA expression profile in cryptococcal meningitis patients. Circ_0001806 was significantly decreased in cryptococcal meningitis individuals. Then the effects of circ_0001806 and its interaction with miRNAs were explored in vivo and in vitro. The knock-down of circ_0001806 led to higher fungal infection and shorter survival in an experimental murine cryptococcosis model. Transcriptome analysis showed that decreased circ_0001806 regulated pathways related to the host antimicrobe response in T cells. Furthermore, in vitro experiments showed that circ_0001806 positively modulates ADM level, decreasing cell apoptosis and G1S arrest in T cells. Finally, we found circ_0001806 exerted its effects by sponging miRNA-126 in T cells. Taken together, our results reveal the role of circRNA-1806/miRNA-126 in the regulation of cell cycle and apoptosis in cryptococcal infection and can provide a new insights of the pathogenesis of cryptococcal infection.

Colonic cryptococcosis as a rare presentation in HIV infection: a case report and review of the literature

Colonic cryptococcal infection is unusual in people living with HIV (PLWH) and even more so without concomitant neurological compromise. Published case reports describe diarrhea and other intestinal manifestations that are often confused with systemic tuberculosis infection. We describe an Peruvian woman living with HIV on antiretroviral therapy who presented hypotensive with a 6-month history of fever and epigastric pain, in addition to episodes of sporadic diarrhea. Due to the suspicion of systemic tuberculosis, antituberculosis treatment was started. Days later, without clinical improvement, colonoscopy revealed ulcers in the transverse colon. Histopathological examination of biopsied tissue was compatible with Cryptococcus spp. She received antifungal therapy with amphotericin B and fluconazole. Despite the treatment, the patient died six days later from multiple organ failure.

The conundrum of clinical trials and standard of care in sub-Saharan Africa - the research nurse perspective

BACKGROUND

Nurses form a very important part of the health workforce in sub-Saharan Africa. Research nurses are critical to the implementation of clinical trials. The duties and responsibilities of a research nurse are complex and continue to evolve as new practices and guidelines are formulated.

AIMS

In this paper, we have highlighted the major contributions of research nurses in HIV clinical trials in sub-Saharan Africa from the unique perspective of Ugandan nurses.

METHODS

The requirements and challenges of two multi-site, randomised cryptococcal meningitis clinical trials in Uganda were assessed from the perspective of research nurses conducting complex research in resource-limited settings.

RESULTS

Over the course of 8 years, approximately 1739 participants were screened and 934 people were enrolled into the two trials. The nurses found that patient education and engagement were among the most important predictors of success in minimising loss to follow-up.

CONCLUSIONS

Research nurses played a key role in communicating clinical research goals to patients, obtaining informed consent, minimising loss to follow-up, and ensuring that research practices are translated and implemented into standard of care. However, there remains a need to integrate the same level of care provided in clinical research studies to non-study patients.

Subtle Cryptococcal Immune Reconstitution Inflammatory Syndrome

Patients with HIV and opportunistic infections (OIs), such as tuberculosis and cryptococcosis, have been recognised to have immune reconstitution inflammatory syndrome (IRIS) following initiation of highly active antiretroviral therapy (HAART). The initiation of HAART boosts CD4 T cells, which result in exacerbations of OIs. We have identified deterioration of neural lesion in imaging after the initiation of HAART in a patient with HIV/cryptococcal infection, although patient's clinical conditions have not deteriorated. It is evident that IRIS is in subtlety. This has been possible because of prompt treatment with antifungal drugs for the cryptococcal infection, followed by early initiation of HAART.

Cryptococcal infection in lung transplant recipients: A 5-year retrospective review at an Australian transplant center

Cryptococcosis is a common invasive fungal infection (IFI) in solid organ transplant (SOT) recipients. Little is known about cryptococcosis in lung transplant (LTx) recipients despite having one of the highest risks of infection. The aim of this study was to describe demographic and clinical features of cryptococcal infection in LTx recipients. We performed a retrospective, observational study of cryptococcal infection in LTx recipients at The Alfred Hospital in Melbourne, Australia, from 2012 to 2017. A total of 11 cases were identified. Seven patients (64%) were male and the median age was 54.7 years (range 34-69 years). Diagnosis occurred at a median of 233 days (range 1-3650 days) post-transplant. Nine patients (82%) had isolated pulmonary infection of whom 7 (78%) were asymptomatic. All were treated with oral antifungal therapy and 1 required surgical resection of infected lung. Two patients (18%) had disseminated infection; 1 with pulmonary and central nervous system (CNS) infection and 1 with isolated CNS infection. Both patients presented with headache and brain imaging demonstrated cerebral edema, myelinosis, and leptomeningeal enhancement. One of these patients died. This study highlights the fact that cryptococcal infection should remain a consideration in asymptomatic LTx recipients, especially in the presence of non-specific nodules on chest imaging, and that the presence of headache in these patients requires urgent investigation for CNS infection.

Disseminated Cryptococcosis Due to Anti-Granulocyte-Macrophage Colony-Stimulating Factor Autoantibodies in the Absence of Pulmonary Alveolar Proteinosis

INTRODUCTION

Autoantibodies to granulocyte-macrophage colony-stimulating factor (GM-CSF) can cause acquired pulmonary alveolar proteinosis (PAP). Cases of acquired PAP susceptible to typical respiratory pathogens and opportunistic infections have been reported. Anti-GM-CSF autoantibodies have been reported in a few patients with cryptococcal meningitis. This study evaluated the presence of neutralizing anti-GM-CSF autoantibodies in patients without known congenital or acquired immunodeficiency with severe pulmonary or extrapulmonary cryptococcal infection but without PAP.

METHODS

We took a clinical history and performed an immunologic evaluation and screening of anti-cytokine autoantibodies in patients with cryptococcal meningitis. The impact of autoantibodies to GM-CSF on immune function was assessed by intracellular staining of GM-CSF-induced STAT5 phosphorylation and MIP-1α production in normal peripheral blood mononuclear cells incubated with plasma from patients or normal control subjects.

RESULTS

Neutralizing anti-GM-CSF autoantibodies were identified in four patients with disseminated cryptococcosis, none of whom exhibited PAP. Plasma from patients blocked GM-CSF signaling and inhibited STAT5 phosphorylation and production of MIP-1α. One patient died of disseminated cryptococcosis involving the central nervous system, which was associated with defective GM-CSF activity.

CONCLUSIONS

Anti-GM-CSF autoantibodies increase susceptibility to cryptococcal infection in adults without PAP. Cryptococcal central nervous system infection associated with anti-GM-CSF autoantibodies could result in neurological sequelae or be life-threatening. Therefore, timely detection of neutralizing anti-GM-CSF autoantibodies and development of an effective therapy are necessary to prevent deterioration of cryptococcal infection in these patients.

Case Report of Cryptococcus Albidus Peritonitis in a Peritoneal Dialysis Patient and a Review of the Literature

Cryptococcus albidus is a saprophytic yeast linked to just 26 reports of human infection in the world literature. Here, we report the first case of C. albidus peritonitis, in a patient with end-stage renal disease and hepatitis C-associated cirrhosis who is on peritoneal dialysis. The patient was treated successfully with a week-long course of amphotericin B. Non-neoformans cryptococcal infections present a clinical challenge, because they are difficult to diagnose and lack established guidelines for treatment. We present a review of the literature on C. albidus infections and their treatment.

Cryptococcus infection in a non-HIV patient: a case report

Cryptococcal infections are fungal infections most commonly seen in immunocompromised patients. Chronic high-dose steroid may precipitate such an immunocompromised state and thus create susceptibility to fungal infections. Cryptococcus neoformans is a saprophyte usually found in soil contaminated with pigeon droppings. Suspicion to diagnose begins with clinical symptoms that can be non-specific such as fevers, cough, and headaches. We present a case of steroid-induced cryptococcal infection in a non-HIV-infected person.

Cytodiagnosis of coexistent cryptococcal and mycobacterial lymphadenitis in a case of AIDS

Multiple infections are a common feature of acquired immunodeficiency syndrome (AIDS), but coexistent infections at the same site are rare. In this report, we describe a 35-year-old human immunodeficiency virus infected male with coexistent cryptococcal and mycobacterial lymphadenitis. He presented with generalised lymphadenopathy. Fine needle aspiration cytology of enlarged cervical lymph node, aided by special stains, revealed coexistent cryptococcal and mycobacterial infection. Coexistent infections pose diagnostic problems in AIDS patients and are likely to be missed. Special stains are valuable for accurate diagnosis of coexistent infections.