Legionellosis and biologic therapies

Area of Science:

• Immunology
• Infectious Diseases
• Rheumatology

Background:

• Biologic therapies are crucial for managing inflammatory diseases.
• These treatments are associated with an increased risk of infections, including granulomatous and intracellular pathogens like Legionella.
• Understanding this risk is vital for patient safety.

Purpose of the Study:

• To investigate the association between biologic therapies and Legionella pneumonia.
• To identify specific biologic agents and patient characteristics linked to this infection.
• To inform clinical awareness and management strategies.

Main Methods:

• A comprehensive review of existing literature was conducted.
• Cases of Legionella pneumonia in patients using biologic therapies were identified and analyzed.
• Data on patient demographics, underlying diseases, specific biologic agents, and concomitant medications were collected.

Main Results:

• 105 cases of Legionella pneumonia were identified in patients on biologic therapies.
• Infliximab (65.3%) and adalimumab (23.5%) were the most frequently implicated biologic agents.
• Patients often had rheumatologic or inflammatory bowel diseases and were frequently treated with concomitant immunosuppressants, particularly steroids. The overall mortality rate was 19%.

Conclusions:

• Legionella pneumonia is a significant potential complication of biologic therapy, especially with infliximab and adalimumab.
• Concomitant use of immunosuppressive drugs, particularly during the initial 6 months of treatment, increases risk.
• Physicians must maintain high awareness for early diagnosis and prompt treatment to reduce severe outcomes.