The acute vasculitis of Wegener's granulomatosis in renal biopsies.

The kidney biopsy specimens from five patients with Wegener's Granulomatosis were reviewed in an attempt to characterize the early histological lesion when vasculitis was present. The vascular lesions were found mainly in interlobular-sized arteries. The acute vascular lesions were sparse and focal, mainly localized to the intimal area, and with fibrinoid material and platelets constituting the early infiltrate. The electron microscopy and scanning electron microscopy of the involved areas further emphasized the presence of platelets in the early lesion, and accentuated endothelial alterations occurring along with the intimal infiltrate. Morphologic evidence of immune complex presence was not found.