Abstract
Antineutrophil cytoplasmic antibodies (ANCAs) are autoantibodies specific for antigens
located in the cytoplasmic granules of neutrophils and lysosomes of monocytes. ANCAs
are associated with a spectrum of necrotizing vasculitis that includes granulomatosis
with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with
polyangiitis. Pulmonary vasculitis and related extravascular inflammation and fibrosis
are frequent components of ANCA vasculitis. In this review, we detail the factors
that have been associated with the origin of the ANCA autoimmune response and summarize
the most relevant clinical observations, in vitro evidence, and animal studies strongly
indicating the pathogenic potential of ANCA. In addition, we describe the putative
sequence of pathogenic mechanisms driven by ANCA-induced activation of neutrophils
that result in small vessel necrotizing vasculitis and extravascular granulomatous
necrotizing inflammation.
Keywords
ANCA - granulomatosis with polyangiitis - microscopic polyangiitis - pulmonary vasculitis
