ANCA: associated lung fibrosis.

The possible link between pulmonary fibrosis, anti-neutrophil cytoplasmic autoantibody (ANCA) positivity, and vasculitis is poorly understood. During the past 6 years, five retrospective case-control studies have been published. These studies suggest that pulmonary fibrosis (PF) is an underestimated manifestation of ANCA-associated vasculitis. Common clinical characteristics include older age (around 70 years), constant positivity of myeloperoxidase (MPO)-ANCA and the poor prognosis of the pulmonary disease. The diagnosis of PF often predates the development of vasculitis. There are no significant differences of pulmonary function parameters, bronchoalveolar lavage analysis, or high-resolution computed tomographic (HRCT) findings between ANCA-associated PF and idiopathic pulmonary fibrosis (IPF). The high mortality rate of ANCA-associated PF indicates that a search for ANCAs should be performed at diagnosis in every patient with PF because the presence of ANCAs increases the risk of development of vasculitis and should promote specific monitoring of patients with positive MPO-ANCA.