Invasive fungal disease and the immunocompromised host including allogeneic hematopoietic cell transplant recipients: Improved understanding and new strategic approach with sargramostim

Clinical aspects and recent advances in fungal diseases impacting human health

Fungal diseases are of growing clinical concern in human medicine as the result of changes in the epidemiology, diversity in clinical presentation, emergence of new pathogens, difficulties in diagnosis and increasing resistance to antifungals of current available classes. There is a need for high disease awareness among the public and healthcare physicians, improvement in diagnostic methods and the development of drugs from new therapeutic classes with an improved resistance profile. In this article, we will explore some key aspects of fungal diseases in humans and provide a general overview of this important topic.

Host-Directed Adjunctive Therapies in Immunocompromised Patients with Pneumonia

Immunocompromised (IC) hosts represent a unique patient population at risk for not only typical pathogens, but also opportunistic microorganisms. While antimicrobials remain the main treatment, new investigations have demonstrated the importance of host-response to pathogens. In this article, we highlight previously discovered and new areas of investigation for adjunctive host-response treatments for IC host pneumonia.

Diagnosis and management of invasive fungal diseases by next-generation sequencing: are we there yet?

INTRODUCTION

Invasive fungal diseases (IFDs) are a serious threat to immunocompromised patients. Routine diagnostic methods have limited performance in identifying IFDs. Next-generation sequencing (NGS), including metagenomic NGS (mNGS) and whole-genome sequencing (WGS), recently emerged as diagnostic methods that could provide more accurate and timely diagnoses and management of IFDs.

AREAS COVERED

This article describes the emergence of NGS as a diagnostic tool to address the limitations of current tests. The literature regarding its application and clinical utility in the diagnosis of IFDs is reviewed. Practical considerations, challenges, and opportunities as they relate to the development and implementation of mNGS and WGS for fungal pathogens are discussed.

EXPERT OPINION

NGS emerged over a decade ago with the potential to solve many of the challenges in diagnosing infectious diseases, including IFDs. However, published literature has yielded conflicting data about its clinical utility. The increased clinical adoption of NGS is improving our understanding of how to interpret and use its results to guide actionable decisions. Still, several gaps remain. As the cost, effort, and expertise involved in performing NGS decrease and the reporting of its results becomes standardized, NGS is poised to fill current gaps in the diagnosis of IFDs.

Treatment of Invasive Pulmonary Aspergillosis and Preventive and Empirical Therapy for Invasive Candidiasis in Adult Pulmonary and Critical Care Patients. An Official American Thoracic Society Clinical Practice Guideline

BACKGROUND

The incidence of invasive fungal infections is increasing in immune-competent and immune-compromised patients. An examination of the recent literature related to the treatment of fungal infections was performed to address two clinical questions. First, in patients with proven or probable invasive pulmonary aspergillosis, should combination therapy with a mold-active triazole plus echinocandin be administered vs. mold-active triazole monotherapy? Second, in critically ill patients at risk for invasive candidiasis who are non-neutropenic and are not transplant recipients, should systemic antifungal agents be administered either as prophylaxis or as empiric therapy?

METHODS

A multidisciplinary panel reviewed the available data concerning the two questions. The evidence was evaluated, and recommendations were generated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

A conditional recommendation was made for patients with proven or probable invasive pulmonary aspergillosis to receive either initial combination therapy with a mold-active triazole plus an echinocandin or initial mold-active triazole monotherapy based on low-quality evidence. Further, a conditional weak recommendation was made against routine administration of prophylactic or empiric antifungal agents targeting Candida species for critically ill patients without neutropenia or a history of transplant based on low-quality evidence.

CONCLUSIONS

The recommendations presented in these Guidelines are the result of an analysis of currently available evidence. Additional research and new clinical data will prompt an update in the future.

Fungal Intracranial Infections (Central Nervous System-Invasive Fungal Disease) in Patients With Haematological Disorders-A Single-Centre Retrospective Study

BACKGROUND

Invasive fungal disease (IFD) is a sinister complication encountered in patients with haematological disorders. When occurring in the central nervous system (CNS), IFDs can have catastrophic outcomes.

OBJECTIVES

To study the clinical presentation, predisposing etiological factors, and prognosis of a CNS-IFD in a patient with a haematological disorder.

PATIENTS AND METHODS

This is a retrospective study focusing on the clinical profile, diagnosis, treatment strategy and outcomes of 43 patients with an underlying haematological disorder, who were diagnosed with CNS-IFD between 2018 and 2022.

RESULTS

Of the 43 patients, 18 were chemotherapy recipients, while 23 were stem cell transplant (SCT) recipients and 2 presented with CNS-IFD at diagnosis. AML/MDS (37.2%) and ALL (18.6%) were the predominant underlying diagnoses. A sudden deterioration in sensorium (53.5%) was the earliest clinical sign, while T2 hyperintensities (26.8%), vascular involvement (26.8%) and ring-enhancing lesions (16.3%) were the commonest radiological findings, with all patients exhibiting diffusion restriction in diffusion-weighted images. Microbiological evidence of infection was obtained in all patients; however, culture positivity was established in only 25 patients. Rhizopus spp (23.2%) and Aspergillus spp (20.9%) were implicated in most cases. Overall survival of the cohort was 27.9% at a median follow-up of 6 months. In patients who succumbed, the median time to death was 4 days (0-46).

CONCLUSION

CNS-IFD is associated with very poor survival in patients undergoing chemotherapy or an SCT, urging the need for prompt diagnosis and initiation of suitable antifungal therapy.

Candida albicans skin infection in diabetic patients: An updated review of pathogenesis and management

Candida species, commensal residents of human skin, are recognized as the cause of cutaneous candidiasis across various body surfaces. Individuals with weakened immune systems, particularly those with immunosuppressive conditions, are significantly more susceptible to this infection. Diabetes mellitus, a major metabolic disorder, has emerged as a critical factor inducing immunosuppression, thereby facilitating Candida colonization and subsequent skin infections. This comprehensive review examines the prevalence of different types of Candida albicans-induced cutaneous candidiasis in diabetic patients. It explores the underlying mechanisms of pathogenicity and offers insights into recommended preventive measures and treatment strategies. Diabetes notably increases vulnerability to oral and oesophageal candidiasis. Additionally, it can precipitate vulvovaginal candidiasis in females, Candida balanitis in males, and diaper candidiasis in young children with diabetes. Diabetic individuals may also experience candidal infections on their nails, hands and feet. Notably, diabetes appears to be a risk factor for intertrigo syndrome in obese individuals and periodontal disorders in denture wearers. In conclusion, the intricate relationship between diabetes and cutaneous candidiasis necessitates a comprehensive understanding to strategize effective management planning. Further investigation and interdisciplinary collaborative efforts are crucial to address this multifaceted challenge and uncover novel approaches for the treatment, management and prevention of both health conditions, including the development of safer and more effective antifungal agents.

New azole derivatives linked to indole/indoline moieties combined with FLC against drug-resistant Candida albicans

Candida albicans is the most common fungal pathogen associated with human opportunistic infections. Invasive infections caused by C. albicans are becoming increasingly serious. However, with the rising incidence of fungal infection, many fungi are resistant to commonly used drugs. Therefore, there is an urgent need for exploring new anti-fungal drugs that fungi are not resistant to. A series of novel azole derivatives linked to indole/indoline moieties were prepared, and in vitro antifungal activity evaluated. All compounds combined with FLC showed excellent activity against drug-resistant C. albicans with low toxicity. A preliminary mechanistic study indicated that S1 combined with FLC could inhibit the formation of C. albicans biofilms as well as destroy the integrity of cell-membrane structure and mitochondrial function. S1 could be considered a new fungal agent for further study.

Pegfilgrastim on febrile neutropenia in pediatric and adolescent cancer patients: a systematic review and meta-analysis

OBJECTIVES

There is no meta-analysis about the effects of pegfilgrastim on the occurrence of febrile neutropenia (FN) in pediatric/adolescent cancer patients. The study explored the efficacy of prophylactic pegfilgrastim in preventing FN in children/adolescents with cancer.

METHODS

PubMed, Embase, and the Cochrane Library were searched for studies published before April 7, 2020. The primary outcome was the rate of FN. Effect size (ES) and odds ratio (OR) with 95% confidence intervals (CIs) were used to evaluate the outcome. The ES represented the rate of FN, and the STATA 'metaprop' command was used to synthesize the rate.

RESULTS

Eight studies were included, comprising 167 patients and 550 courses of treatment. There was no difference between pegfilgrastim and filgrastim for the rate of FN in children receiving chemotherapy (OR = 0.68, 95% CI: 0.20-2.23, P = 0.520). In patients receiving pegfilgrastim, the rate of FN was 25.6% (95% CI: 14.9%-36.3%), the rate of grade 4 FN was 38.3% (95% CI: 19.2%-59.5%), the rate of severe neutropenia (SN) was 40.5% (95% CI: 35.1%-46.1%), and the rate of treatment delays due to FN was 4.8% (95% CI: 0.8%-11.3%).

DISCUSSION

The number of studies that could be included was small; therefore, a specific type of cancer or a specific treatment could be studied. Heterogeneity was high.

CONCLUSION

There was no difference between pegfilgrastim and filgrastim for the rate of FN. The use of pegfilgrastim was still associated with rates of FN, grade 4 FN, severe neutropenia, and treatment delays due to FN in pediatric cancer patients.

The outcome and the risk factors of mucormycosis among patients with hematological diseases: a systematic and meta-analysis

Objectives

Mucorale has come into a significant pathogen over recent decades. Nonetheless, mucormycosis-related mortality rates among patients with hematological disorders remain unascertained. Thus, we conducted a meta-analysis to determine mortality rates of mucormycosis in patients with hematology-related conditions.

Methods

We scoured PubMed, Embase, and Web of Science for original papers exploring the intersection of Mucormycosis and Hematological Diseases (from 2000 to 2022). We scrutinized the overall mortality across three distinct periods, as well as differentiating between high-income and middle-income nations. We further evaluated the pooled mortality and the risk differential (RD) across several subgroups.

Results

The overall mortality rate for hematology patients with mucormycosis was 61%, within a 95% confidence interval (CI) of 0.54-0.68. A significant observation was that mortality rates were somewhat lower in high-income countries compared to middle-income countries (0.60 versus 0.64, p = 0.45). Importantly, we discovered that a combination of surgical and medical treatment significantly improved survival rates compared to medical treatment alone [mortality 0.49 versus 0.67, RD -0.19 (95%CI -0.38-0.00, I2 63.7%)]. As might be expected, disseminated mucormycosis posed a significantly higher risk of death compared to isolated mucormycosis [0.60 versus 0.57, RD death 0.16 (95%CI 0.03-0.28)]. Additionally, our analysis showed no discernible differences in survival rates between genders, between patients with and without breakthrough infection, between those who received mucor-active or mucor-inactive drugs prior to mucor infection, or between those on a multi-drug regimen and those on a single drug treatment.

Conclusion

Despite the high mortality rates associated with mucormycosis in patients with hematological disorders, those receiving both medical and surgical interventions, as well as those with isolated infection sites, exhibited improved survival outcomes. Conversely, factors such as gender, the presence of breakthrough infection, the use of mucor-active drugs before mucor infection, and multi-drug administration did not significantly influence patient outcomes.

Risk Factors, Prevalence, and Outcomes of Invasive Fungal Disease Post Hematopoietic Cell Transplantation and Cellular Therapies: A Retrospective Monocenter Real-Life Analysis

(1) Background: Autologous, allogeneic hematopoietic cell transplantation (HCT) and other cellular therapies, including CAR T cell and gene therapy, constitute a cornerstone in the management of various benign and malignant hematological disorders. Invasive fungal infections (IFD) remain a significant cause of morbidity and mortality in HCT recipients. Therefore, we investigated the prevalence and risk factors of IFD following HCT and other cellular therapies in an era of novel antifungal prophylaxis. (2) Methods: In this study, we retrospectively enrolled adult HCT recipients who were treated at our JACIE-accredited center according to standard operating procedures over the last decade (2013-2022). (3) Results: 950 patients who received cellular therapies were studied. None of the 19 CAR T cell and neither of the two gene therapy recipients developed IFD whereas 3/456 autologous HCT recipients who suffered from primary refractory/relapsed lymphomas presented with probable IFD. Overall, 11 patients who received allogeneic HCT experienced probable IFD, possible IFD was found in 31/473, and IFD was proven in 10/473. A second IFD episode was present in three patients. Four-year OS was significantly lower in proven compared to probable IFD (p = 0.041) and was independently associated with HCT-CI (p = 0.040) and chronic GVHD (p = 0.045). (4) Conclusions: In this real-world cohort, the prevalence of proven and probable IFD in an era of novel antifungal prophylaxis was found to be relatively low. However, IFDs were associated with poor outcomes for patients who received allogeneic HCT.

Recombinant GM-CSF for diseases of GM-CSF insufficiency: Correcting dysfunctional mononuclear phagocyte disorders

Introduction

Endogenous granulocyte-macrophage colony-stimulating factor (GM-CSF), identified by its ability to support differentiation of hematopoietic cells into several types of myeloid cells, is now known to support maturation and maintain the metabolic capacity of mononuclear phagocytes including monocytes, macrophages, and dendritic cells. These cells sense and attack potential pathogens, present antigens to adaptive immune cells, and recruit other immune cells. Recombinant human (rhu) GM-CSF (e.g., sargramostim [glycosylated, yeast-derived rhu GM-CSF]) has immune modulating properties and can restore the normal function of mononuclear phagocytes rendered dysfunctional by deficient or insufficient endogenous GM-CSF.

Methods

We reviewed the emerging biologic and cellular effects of GM-CSF. Experts in clinical disease areas caused by deficient or insufficient endogenous GM-CSF examined the role of GM-CSF in mononuclear phagocyte disorders including autoimmune pulmonary alveolar proteinosis (aPAP), diverse infections (including COVID-19), wound healing, and anti-cancer immune checkpoint inhibitor therapy.

Results

We discuss emerging data for GM-CSF biology including the positive effects on mitochondrial function and cell metabolism, augmentation of phagocytosis and efferocytosis, and immune cell modulation. We further address how giving exogenous rhu GM-CSF may control or treat mononuclear phagocyte dysfunction disorders caused or exacerbated by GM-CSF deficiency or insufficiency. We discuss how rhu GM-CSF may augment the anti-cancer effects of immune checkpoint inhibitor immunotherapy as well as ameliorate immune-related adverse events.

Discussion

We identify research gaps, opportunities, and the concept that rhu GM-CSF, by supporting and restoring the metabolic capacity and function of mononuclear phagocytes, can have significant therapeutic effects. rhu GM-CSF (e.g., sargramostim) might ameliorate multiple diseases of GM-CSF deficiency or insufficiency and address a high unmet medical need.

How to improve the outcomes of elderly acute myeloid leukemia patients through allogeneic hematopoietic stem cell transplantation

In recent years, with the gradual advancement of haploidentical transplantation technology, the availability of donors has increased significantly, along with the widespread use of reduced-intensity conditioning and the improvement of nursing techniques, giving more elderly acute myeloid leukemia (AML) patients the chance to receive allogeneic hematopoietic stem cell transplantation. We have summarized the classic and recently proposed pre-transplant assessment methods and assessed the various sources of donors, conditioning regimens, and post-transplant complication management based on the outcomes of large-scale clinical studies for elderly AML patients.

Evaluation of Candidiasis in Upper-Aerodigestive Squamous Cell Carcinoma Patients—A Clinico-Mycological Aspect

Candida is a commensal yeast. It can be infective when the host’s defense mechanism is weakened, as in the case of squamous cell carcinoma patients. We aimed to evaluate the prevalence and clinical mycological manifestation of candidiasis in 150 cancer cases comprised of preoperative and post-operative (with or without radiotherapy) upper aerodigestive squamous cell carcinoma. A total of 150 patients suffering from squamous cell carcinoma of the Upper Aero-Digestive Tract (UADT) were divided into preoperative (n = 48), post-operative without radiotherapy (n = 29) and post-operative with radiotherapy (n = 73). Samples were collected using cotton swabs and cultured. Candida species were identified according to color pigmentation on Candida Differential Agar (CDA) plate. The clinico-mycological association of patients was evaluated by the chi-square test, and 98 out of 150 patients showed the presence of various Candida species. The major species isolated was Candida albicans (53%), followed by Candida tropicalis (16%). There was a significant statistical difference between patients who showed mycological associations and patients who did not have any such association (p = 0.0008). The prevalence of oral candidiasis was found to be 65.33% among total cases of upper aero-digestive squamous cell carcinoma. Chronic erythematous cases of candidiasis were mainly seen in preoperative squamous cell carcinoma cases, whereas the acute erythematous type of candidiasis was mainly seen in post-operative cases who received radiotherapy. The clinicomycological assessment can help to correlate the signs and symptoms with the presence of candidiasis in upper aerodigestive squamous cell carcinoma patients. Meticulous testing and examination can help in the early detection of candidiasis. Future studies are needed to develop advance scientific preventive strategies for high-risk cases.

Distribution of Yeast Species and Risk Factors of Oral Colonization after Oral-Care Education among the Residents of Nursing Homes

Most yeasts causing infections in humans are part of commensal microflora and etiological agents of different infections when hosts become susceptible, usually due to becoming immunocompromised. The colonization of potentially pathogenic microbes in the oral cavity is increased by poor oral hygiene. This follow-up survey was conducted approximately two months after providing information on proper oral care at 10 nursing homes in Taiwan. Among the 117 of 165 residents colonized by yeasts, 67 were colonized by more than one yeast species. A total of 231 isolates comprising eight fungal genera and 25 species were identified. Candida albicans (44.6%) was the dominant species, followed by Candida glabrata (17.7%), Candida parapsilosis (8.7%), Candida tropicalis (7.8%), and Candida pararugosa (7.3%). Residents having a yeast colony-forming unit >10 (OR, 8.897; 95% CI 2.972−26.634; p < 0.001) or using a wheelchair (OR, 4.682; 95% CI 1.599−13.705; p = 0.005) were more likely to be colonized by multiple species. By comparing before and after oral-care education, dry mouth (OR, 3.199; 95% CI 1.448−7.068; p = 0.011) and having heart disease (OR, 2.681; 95% CI 1.068−6.732; p = 0.036) emerged as two independent risk factors for increased density of colonizing yeast.

LncRNA: A Potential Target for Host-Directed Therapy of Candida Infection

Despite various drugs work against Candida, candidiasis represents clinical management challenges worldwide due to the rising incidence and recurrence rate, as well as epidemics, of new drug-resistant pathogens. Recent insights into interactions between Candida and hosts contribute to exploring novel therapeutic strategies, termed host-directed therapies (HDTs). HDTs are viable adjuncts with good efficacy for the existing standard antifungal regimens. However, HDTs induce other response unintendedly, thus requiring molecular targets with highly specificity. Long noncoding RNAs (lncRNAs) with highly specific expression patterns could affect biological processes, including the immune response. Herein, this review will summarize recent advances of HDTs based on the Candida–host interaction. Especially, the findings and application strategies of lncRNAs related to the host response are emphasized. We propose it is feasible to target lncRNAs to modulate the host defense during Candida infection, which provides a new perspective in identifying options of HDTs for candidiasis.

Radionuclide Imaging of Invasive Fungal Disease in Immunocompromised Hosts

Invasive fungal disease (IFD) leads to increased mortality, morbidity, and costs of treatment in patients with immunosuppressive conditions. The definitive diagnosis of IFD relies on the isolation of the causative fungal agents through microscopy, culture, or nucleic acid testing in tissue samples obtained from the sites of the disease. Biopsy is not always feasible or safe to be undertaken in immunocompromised hosts at risk of IFD. Noninvasive diagnostic techniques are, therefore, needed for the diagnosis and treatment response assessment of IFD. The available techniques that identify fungal-specific antigens in biological samples for diagnosing IFD have variable sensitivity and specificity. They also have limited utility in response assessment. Imaging has, therefore, been applied for the noninvasive detection of IFD. Morphologic imaging with computed tomography (CT) and magnetic resonance imaging (MRI) is the most applied technique. These techniques are neither sufficiently sensitive nor specific for the early diagnosis of IFD. Morphologic changes evaluated by CT and MRI occur later in the disease course and during recovery after successful treatment. These modalities may, therefore, not be ideal for early diagnosis and early response to therapy determination. Radionuclide imaging allows for targeting the host response to pathogenic fungi or specific structures of the pathogen itself. This makes radionuclide imaging techniques suitable for the early diagnosis and treatment response assessment of IFD. In this review, we aimed to discuss the interplay of host immunity, immunosuppression, and the occurrence of IFD. We also discuss the currently available radionuclide probes that have been evaluated in preclinical and clinical studies for their ability to detect IFD.

Sargramostim (rhu GM-CSF) as Cancer Therapy (Systematic Review) and An Immunomodulator. A Drug Before Its Time?

BACKGROUND

Sargramostim [recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF)] was approved by US FDA in 1991 to accelerate bone marrow recovery in diverse settings of bone marrow failure and is designated on the list of FDA Essential Medicines, Medical Countermeasures, and Critical Inputs. Other important biological activities including accelerating tissue repair and modulating host immunity to infection and cancer via the innate and adaptive immune systems are reported in pre-clinical models but incompletely studied in humans.

OBJECTIVE

Assess safety and efficacy of sargramostim in cancer and other diverse experimental and clinical settings.

METHODS AND RESULTS

We systematically reviewed PubMed, Cochrane and TRIP databases for clinical data on sargramostim in cancer. In a variety of settings, sargramostim after exposure to bone marrow-suppressing agents accelerated hematologic recovery resulting in fewer infections, less therapy-related toxicity and sometimes improved survival. As an immune modulator, sargramostim also enhanced anti-cancer responses in solid cancers when combined with conventional therapies, for example with immune checkpoint inhibitors and monoclonal antibodies.

CONCLUSIONS

Sargramostim accelerates hematologic recovery in diverse clinical settings and enhances anti-cancer responses with a favorable safety profile. Uses other than in hematologic recovery are less-well studied; more data are needed on immune-enhancing benefits. We envision significantly expanded use of sargramostim in varied immune settings. Sargramostim has the potential to reverse the immune suppression associated with sepsis, trauma, acute respiratory distress syndrome (ARDS) and COVID-19. Further, sargramostim therapy has been promising in the adjuvant setting with vaccines and for anti-microbial-resistant infections and treating autoimmune pulmonary alveolar proteinosis and gastrointestinal, peripheral arterial and neuro-inflammatory diseases. It also may be useful as an adjuvant in anti-cancer immunotherapy.