International consensus on antineutrophil cytoplasm antibodies testing in eosinophilic granulomatosis with polyangiitis

An international consensus on antineutrophil cytoplasm antibodies (ANCA) testing in eosinophilic granulomatosiswith polyangiitis (EGPA) is presented.ANCA, specific formyeloperoxidase (MPO), can be detected in 30-35% of patients with EGPA. MPO-ANCA should be tested with antigen-specific immunoassays in any patient with eosinophilic asthma and clinical features suggesting EGPA, including constitutional symptoms; purpura; polyneuropathy; unexplained heart, gastrointestinal, or kidney disease; and/or pulmonary infiltrates or hemorrhage.Apositive MPO-ANCA result contributes to the diagnostic workup for EGPA. Patients with MPO-ANCA-associated EGPA have vasculitis features, such as glomerulonephritis, neuropathy, and skin manifestations, more frequently than patients with ANCA-negative EGPA. However, the presence of MPO-ANCA is neither sensitive nor specific enough to identifywhether a patient should be subclassified as having "vasculitic"or "eosinophilic"EGPA. At present, ANCA status cannot guide treatment decisions, that is,whether cyclophosphamide, rituximab, ormepolizumab should be added to conventional glucocorticoid treatment. In EGPA, monitoring of ANCA is only useful when MPO-ANCA was tested positive at disease onset.