Histoplasmosis in transplant recipients

Area of Science:

• Mycology
• Infectious Diseases
• Transplant Medicine

Background:

• Histoplasma capsulatum causes asymptomatic infections in immunocompetent individuals.
• Immunocompromised patients, especially solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients, are at high risk for severe, life-threatening Histoplasma infections.
• Post-transplant histoplasmosis (PTH) is uncommon (≤1% in SOT, rarer in HCT) and typically occurs within two years of transplantation.

Purpose of the Study:

• To review the epidemiology, clinical presentation, diagnosis, and management of post-transplant histoplasmosis.
• To highlight the challenges in diagnosing and treating this opportunistic fungal infection in transplant recipients.

Main Methods:

• Review of existing literature on post-transplant histoplasmosis.
• Analysis of clinical features, diagnostic methods, and treatment outcomes.

Main Results:

• PTH can arise from reactivation, de novo infection, or donor transmission, often presenting as disseminated disease.
• Fever is the most common symptom; clinical signs can be nonspecific, potentially mimicking sepsis.
• Histoplasma antigen assays are sensitive but may show cross-reactivity; antigen levels are valuable for prognosis and monitoring treatment response.
• Treatment duration should be at least one year, with an attributable mortality of approximately 10%.

Conclusions:

• Post-transplant histoplasmosis requires prompt recognition and prolonged treatment in at-risk populations.
• Current evidence does not support routine screening of donors and recipients for Histoplasma.
• Monitoring Histoplasma antigen levels is essential for guiding therapy and assessing patient outcomes.