Platelet dysfunction contributes to bleeding complications in patients with probable leptospirosis

Area of Science:

• Hematology
• Infectious Diseases
• Pathophysiology

Background:

• Severe leptospirosis often causes hemorrhagic diathesis with unknown pathogenesis.
• Thrombocytopenia is common but insufficient to explain spontaneous bleeding.
• Hypothesis: Hemorrhagic complications involve platelet dysfunction and increased VWF binding to platelets, affecting platelet clearance.

Purpose of the Study:

• Investigate platelet activation, reactivity, and VWF binding in leptospirosis patients with bleeding.
• Determine the role of VWF-platelet interactions in hemorrhagic complications and platelet clearance.

Main Methods:

• Prospective study of 33 hospitalized leptospirosis patients and 25 controls.
• Flow cytometry used to assess platelet activation (P-selectin) and αIIbβ3 integrin activation (fibrinogen binding).
• Measured VWF binding, plasma VWF, ADAMTS13, TAT, and P-selectin levels; graded bleeding using WHO scale.

Main Results:

• Platelet activation and dysfunction observed in leptospirosis, particularly in patients with bleeding.
• Significant inverse correlation between bleeding score and TRAP-stimulated P-selectin/platelet-fibrinogen binding, independent of platelet count.
• Patients with bleeding showed higher platelet-VWF binding, inversely correlated with platelet count.

Conclusions:

• Platelet dysfunction is prevalent in leptospirosis patients with bleeding.
• Increased VWF-platelet binding likely contributes to platelet activation and clearance, exacerbating bleeding complications.