A New Therapy Against a Global Fungal Threat

Scientists at The Lundquist Institute and UCLA have reported encouraging findings that could help address one of the world's most dangerous emerging fungal pathogens: Candida auris. In a newly published study in Frontiers in Immunology, researchers demonstrated that treatment with granulocyte-macrophage colony-stimulating factor (GM-CSF) significantly improved survival and enhanced antifungal immunity in immunosuppressed mice suffering from systemic C. auris infection.

Since its discovery in 2009, Candida auris has become a major healthcare concern due to its ability to cause hospital outbreaks, persist on surfaces, resist multiple antifungal drugs, and cause life-threatening bloodstream infections in vulnerable patients. Mortality rates associated with invasive C. auris infections remain alarmingly high, particularly among immunocompromised individuals.

Why New Approaches Are Needed

Current antifungal therapies face increasing challenges because many C. auris isolates are resistant to commonly used antifungal drug classes. While new antifungal agents are under development, the growing threat of drug resistance has prompted researchers to explore therapies that strengthen the patient's own immune defenses.

GM-CSF is an FDA-approved immune-stimulating cytokine already used clinically to boost white blood cell recovery after chemotherapy and bone marrow transplantation. The research team hypothesized that GM-CSF could enhance the immune system's ability to fight C. auris, particularly in patients with weakened immune defenses.

Key Findings from the Study

Using a clinically relevant immunosuppressed mouse model of disseminated C. auris infection, the investigators evaluated GM-CSF alone and in combination with a low dose of the antifungal drug micafungin.

The results were striking:

• GM-CSF monotherapy increased survival from 0% in untreated mice to approximately 32%.

• Combination therapy with GM-CSF and micafungin increased survival to nearly 56%.

• GM-CSF treatment significantly reduced fungal burden in the kidneys, heart, and brain, the major organs targeted by systemic infection.

• Histological analyses showed fewer fungal lesions and less tissue damage in treated animals.

These findings suggest that stimulating host immunity can substantially improve outcomes even in the setting of severe multidrug-resistant fungal infection.

How GM-CSF Strengthens Antifungal Immunity

The study revealed several mechanisms underlying the protective effects of GM-CSF.

Researchers found that GM-CSF:

• Increased the number of immune cells involved in antifungal defense, including neutrophils and macrophages.

• Enhanced fungal uptake and clearance by these immune cells.

• Boosted production of reactive oxygen species (ROS), an important antimicrobial mechanism.

• Increased neutrophil extracellular trap (NET) formation, helping immune cells capture and kill fungal pathogens.

• Reduced fungal-induced damage to immune cells themselves, allowing them to remain effective longer during infection.

Together, these effects resulted in a stronger and more coordinated immune response against C. auris.

Potential Clinical Impact

Although the study was conducted in mice, the findings carry important translational implications. Because GM-CSF is already approved for human use in other clinical settings, its repurposing as an adjunctive therapy for invasive fungal infections could potentially accelerate clinical development.

Host-directed immunotherapies are becoming increasingly attractive as antimicrobial resistance continues to rise worldwide. Rather than targeting the pathogen directly, these approaches empower the immune system to combat infection more effectively.

For immunocompromised patients—including transplant recipients, cancer patients receiving chemotherapy, and individuals with severe immune dysfunction—such strategies may offer an important complement to conventional antifungal treatment.

Looking Ahead

While additional studies are needed to evaluate safety, optimal dosing, and efficacy against multiple C. auris strains, the current work provides strong proof-of-concept support for GM-CSF as an adjunctive immunotherapy.

The authors conclude that GM-CSF has the potential to become part of a multi-pronged strategy against multidrug-resistant fungal infections, helping overcome some of the limitations of current antifungal drugs. Future clinical trials will be required to determine whether these promising results can be translated into benefits for patients.

Citation

Mattos EC, Das Gupta K, Quintanilla D, Hautau H, Ibrahim AS, and Singh S. Adjunctive GM-CSF therapy enhances host defense against systemic Candida auris infection in immunosuppressed mice. Frontiers in Immunology. Published January 19, 2026. DOI: 10.3389/fimmu.2025.1731315. [Frontiers...essed mice]

Keywords: Candida auris, GM-CSF, Immunotherapy, Antifungal Immunity, Drug Resistance, Neutrophils, Macrophages, Infectious Diseases, Fungal Pathogens.