Lung involvement in ANCA-associated vasculitis.

Lung involvement is one of the most common clinical features in ANCA-associated vasculitides (AAV), including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). In this review, we detail the five main presentations of pulmonary involvement in AAV: necrotizing granulomatous inflammation, tracheobronchial inflammation, pulmonary capillaritis, interstitial lung disease (ILD) and asthma with their clinical, radiological and therapeutic characteristics. The prevalence of these manifestations is variable according to the subtype of AAV, necrotizing granulomatous inflammation and tracheobronchial inflammation being defining features of GPA whereas ILD is primarily seen in patients with MPA, especially in association with ANCA directed against myeloperoxydase (MPO-ANCA), and asthma is characteristic of EGPA. Despite recent progresses in the diagnosis and management of these conditions, several questions remain and are discussed here, including local treatments for subglottic stenosis, the uncertain efficacy of plasma exchanges for alveolar hemorrhage, the potential role of antifibrotic agents in ILD associated with MPA, and the use of novel anti-IL-5 strategies in EGPA.

Limited pulmonary MPA, a new MPA entity? A rheumatologist's perspective.

Microscopic polyangiitis (MPA) frequently involves the lungs. However, as opposed to granulomatosis with polyangiitis (Wegener's), limited forms are not recognised. In recent years, cases have been reported in which the lungs were affected without other organ manifestations. For years, many have been labelled as idiopathic pulmonary fibrosis (IPF). In this review, support for the existence of a limited form of MPA affecting the lungs as well as questions and discussions concerning the similarities and differences to IPF are offered.