In situ evidence of pulmonary endothelial activation in patients with granulomatosis with polyangiitis and systemic sclerosis.

Introduction: The aim of this study was to investigate the in situ pulmonary endothelial activation in lung lesions of granulomatosis with polyangiitis (GPA) and systemic sclerosis (SScl).

Methods: We examined the endothelial expression of ICAM-1, VCAM-1, and E-selectin using immunohistochemistry on formalin-fixed, paraffin-embedded sections of lung lesions of GPA, interstitial lung disease associated with SScl and controls.

Results: A significantly enhanced expression of ICAM-1 and E-selectin was observed in GPA and SScl pulmonary endothelium compared to controls. VCAM-1 was more pronouncedly expressed in GPA compared to SScl.

Conclusion: These observations are an evidence of in situ pulmonary vascular endothelial activation in lesions of GPA and SScl, adding information to the pathogenic knowledge of both diseases.