BTK Inhibitors Impair Platelet-Mediated Antifungal Activity

Area of Science:

• Immunology and hematology
• Pharmacology and drug discovery

Background:

• Bruton's tyrosine kinase (BTK) inhibitors have improved outcomes for B-cell malignancies like chronic lymphocytic leukemia (CLL).
• Opportunistic fungal infections, particularly invasive aspergillosis (IA), are increasingly reported in patients treated with BTK inhibitors.
• The role of platelets in controlling fungal infections, though previously identified, is often overlooked in clinical IA management.

Purpose of the Study:

• To investigate the impact of BTK inhibitors on platelet immune function against Aspergillus fumigatus.
• To explore whether impaired platelet function contributes to the increased risk of IA in patients receiving BTK inhibitors.

Main Methods:

• Experimental confirmation of the antifungal role of platelets.
• Assessment of platelet immune functions, including adherence to conidia, activation (P-selectin expression), and direct killing activity, following exposure to BTK inhibitors in vitro.
• Evaluation of platelet response to Aspergillus fumigatus.

Main Results:

• Platelets exhibit a direct antifungal role against Aspergillus fumigatus.
• Exposure to BTK inhibitors significantly impairs key platelet immune functions, including adherence to fungal conidia and activation.
• BTK inhibitor exposure reduces the direct fungal killing capacity of platelets.

Conclusions:

• BTK inhibitors negatively affect platelet immune functions crucial for combating fungal infections.
• The antiplatelet effects of BTK inhibitors may represent a novel contributing factor to the elevated risk of invasive aspergillosis in CLL patients.
• This study highlights the importance of considering platelet function in the context of BTK inhibitor therapy and IA risk.