Vasculitis associated with anti-neutrophil cytoplasm antibodies (ANCA) is a group of rare and severe autoimmune diseases, encompassing several entities: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (PMA), and eosinophilic granulomatosis with polyangiitis (GEPA). When untreated, these diseases are fatal in a matter of months. Currently, thanks to the use of corticosteroids and immunosuppressants, this high mortality has greatly decreased and these are now chronic diseases. On the other hand, these patients are at high risk of morbidity, linked to both relapses (occurring in at least 50% of patients) and side effects of treatments. It is therefore essential to be able to define which patients are at risk of relapse and justify long-term immunosuppressive treatment to avoid recurrence of the disease, and conversely which patients have a low risk of relapse and in whom immunosuppressive treatments can be discontinued to limit the risk of side effects. However, so far no predictor or biomarker can accurately assess this risk of relapse.
As rare disease, vasculitis affects a small number of patients, the cohorts available in the literature are few and the pathophysiological mechanisms remain to be elucidated. The collection of standardized data within a patientheque as part of a multi-year follow-up will facilitate the study of the characteristics of these diseases. This may, in particular, address the main objective of identifying predictors of relapse, as well as secondary objectives for predictive factors of mortality, infectious, cardiovascular or neoplastic complications that affect the prognosis of vasculitis in order to establish a more appropriate management of the patients concerned.