Eosinophilia in Wegener's granulomatosis

Significant eosinophilia is a prominent feature in Churg-Strauss syndrome b ut has only rarely been described in Wegener's granulomatosis (WG). We desc ribe two Wegener's granulomatosis patients with > 30% eosinophilia on their initial presentations, Other etiologies that could account for their eosin ophilia were excluded. Both patients had pulmonary alveolar hemorrhage, sin usitis, arthritis, high-titer cytoplasmic antineutrophil cytoplasmic antibo dies (cANCA), and proteinase-3 antibodies, but no evidence of renal disease . Herein we discuss eosinophilia, the differential diagnosis of pulmonary i nfiltrates and eosinophilia, the role of cANCA in vasculitis and autoimmune disease, compare Wegener's granulomatosis and Churg-Strauss syndrome, and review possible pathogenic mechanisms.