Immunological aspects of Candida and Aspergillus systemic fungal infections

Diagnostic value of serum human Galactomannan aspergillus antigen and 1,3-beta-D-glucan in immunocompromised patient suspected fungal infection

BACKGROUND

The prevalence of fungal infection (FI) in developing countries is high, but the diagnosis of FI is still challenging to determine, so it is needed evaluation of biomarkers other than microbiological culture, because the culture has low sensitivity, high cost, not available in every laboratory and needs a long time. The detection of human galactomannan Aspergillus antigen (GAL) and 1,3-beta-D-glucan (BDG) on the fungal cell wall could be the promising biomarkers for fungal infection. Neutropenia, lymphopenia and CD4T cells in the immunocompromised patients are essential factors, but these cell associations with BDG and GAL levels have not been evaluated yet. The study aimed to evaluate GAL and BDG for detecting fungal infection and their association with total leucocyte count, neutrophil, monocyte, lymphocyte and CD4T cells.

METHOD

A cross-sectional study was conducted among 86 patient with suspected FI. Fungal infection established using EORTC/MSG criteria. Serology test performed using ELISA. Leucocyte cells were measured using a haematology autoanalyser, and CD4T cells were analysed using BD FACSPresto. Statistical analysis obtained using Spearman's correlation coefficient, ROC curve analysis and 2 × 2 contingency table.

RESULTS

Serum Galactomannan and BDG had a significant correlation with CD4T cells and total lymphocyte count (p < 0.05). The cut-off OD GAL >0.3 had sensitivity 54.6%, specificity 87.5% and AUC 0.71; meanwhile, the BDG cut-off >115.78 pg/ mL had sensitivity 71.2%, specificity 52.4% and AUC 0.63 for detecting fungal infection.

CONCLUSIONS

The immunocompromised patients can undergo GAL for determining the diagnose of FI. The lower the CD4T cells and total lymphocyte count, the higher the GAL and BDG serum levels.

Fungal natural products galaxy: Biochemistry and molecular genetics toward blockbuster drugs discovery

Secondary metabolites synthesized by fungi have become a precious source of inspiration for the design of novel drugs. Indeed, fungi are prolific producers of fascinating, diverse, structurally complex, and low-molecular-mass natural products with high therapeutic leads, such as novel antimicrobial compounds, anticancer compounds, immunosuppressive agents, among others. Given that these microorganisms possess the extraordinary capacity to secrete diverse chemical scaffolds, they have been highly exploited by the giant pharma companies to generate small molecules. This has been made possible because the isolation of metabolites from fungal natural sources is feasible and surpasses the organic synthesis of compounds, which otherwise remains a significant bottleneck in the drug discovery process. Here in this comprehensive review, we have discussed recent studies on different fungi (pathogenic, non-pathogenic, commensal, and endophytic/symbiotic) from different habitats (terrestrial and marines), the specialized metabolites they biosynthesize, and the drugs derived from these specialized metabolites. Moreover, we have unveiled the logic behind the biosynthesis of vital chemical scaffolds, such as NRPS, PKS, PKS-NRPS hybrid, RiPPS, terpenoids, indole alkaloids, and their genetic mechanisms. Besides, we have provided a glimpse of the concept behind mycotoxins, virulence factor, and host immune response based on fungal infections.

Candida bloodstream infection in patients with systemic autoimmune diseases

OBJECTIVES

To describe the epidemiological, clinical and microbiological characteristics and mortality of patients with Candida bloodstream infection and systemic autoimmune diseases.

METHODS

We performed a retrospective multicenter study of candidemia in adults with systemic autoimmune diseases between 2010 and 2016.

RESULTS

Among 1040 patients with candidemia, 36 (3.5%) had a systemic autoimmune disease. The most common systemic autoimmune disease was rheumatoid arthritis (27.8%). The most common species was Candida albicans (66.7%). Twenty-two (61.1%) patients received a corticosteroid therapy and nine (25%) received an immunosuppressive therapy at the time of candidemia. The mortality rate was 27.8%.

CONCLUSIONS

Systemic autoimmune diseases are not common in patients with candidemia. The unadjusted mortality rate was comparable to other candidemia studies in the general population.

Immunity against Fungal Infections

Fungal diseases are major causes of morbidity and mortality among the immunocompromised, including HIV-infected individuals and patients with cancer. Individuals without a weakened immune system can also suffer from these infections. Not surprisingly, fungi are a major target for the immune system, rendered visible to it by expression of pathogen-associated molecular patterns/signatures. We now appreciate the roles of both innate and adaptive immunity in eliminating fungal infections, and how a disproportionate or inadequate immune response can diminish the host's capacity to eliminate fungi. This review focuses on our current understanding of the roles of innate and adaptive immunity in clearing common and emergent fungal pathogens. A clearer understanding of how the host's immune response tackles fungal infection may provide useful clues as to how we might develop new agents to treat those diseases in the future.

Optimizing Outcomes in Immunocompromised Hosts: Understanding the Role of Immunotherapy in Invasive Fungal Diseases

A major global concern is the emergence and spread of systemic life-threatening fungal infections in critically ill patients. The increase in invasive fungal infections, caused most commonly by Candida and Aspergillus species, occurs in patients with impaired defenses due to a number of reasons such as underlying disease, the use of chemotherapeutic and immunosuppressive agents, broad-spectrum antibiotics, prosthetic devices and grafts, burns, neutropenia and HIV infection. The high morbidity and mortality associated with these infections is compounded by the limited therapeutic options and the emergence of drug resistant fungi. Hence, creative approaches to bridge the significant gap in antifungal drug development needs to be explored. Here, we review the potential anti-fungal targets for patient-centered therapies and immune-enhancing strategies for the prevention and treatment of invasive fungal diseases.

New insights on the development of fungal vaccines: from immunity to recent challenges

Fungal infections are emerging as a major problem in part due to high mortality associated with systemic infections, especially in the case of immunocompromised patients. With the development of new treatments for diseases such as cancer and the acquired immune deficiency syndrome pandemic, the number of immunosuppressed patients has increased and, as a consequence, also the number of invasive fungal infections has increased. Several studies have proposed new strategies for the development of effective fungal vaccines. In addition, better understanding of how the immune system works against fungal pathogens has improved the further development of these new vaccination strategies. As a result, some fungal vaccines have advanced through clinical trials. However, there are still many challenges that prevent the clinical development of fungal vaccines that can efficiently immunise subjects at risk of developing invasive fungal infections. In this review, we will discuss these new vaccination strategies and the challenges that they present. In the future with proper investments, fungal vaccines may soon become a reality.