Cluster analysis to explore subclassification of eosinophilic granulomatosis with polyangiitis (Churg–Strauss)

Eosinophilic Granulomatosis With Polyangiitis: Dissecting the Pathophysiology

Eosinophilic Granulomatosis with Polyangiitis (EGPA) is a rare multisystemic disease classified both amongst hypereosinophilic disorders and ANCA-associated vasculitis. Vessel inflammation and eosinophilic proliferation are the hallmarks of the disease and main effectors of organ damage. Two distinct disease phenotypes have classically been described according to ANCA-status: the ANCA-negative subset with eosinophil-driven manifestation and the ANCA-positive one with vasculitic manifestations. An analogous dichotomization has also been backed by histological findings and a distinct genetic background. EGPA is typically consider a Th2-mediated disease and blood and tissue eosinophilia represent the cornerstone of diagnosis. Besides, ANCA are known for inducing endothelial injury and vascular inflammation by activating the circulating neutrophils. Thus, the pathogenesis of EGPA seems to be mediated by two coexisting mechanisms. However, the verbatim application of this strict dualism cannot always be translated into routine clinical practice. In the present review we describe the current knowledge on the eosinophilic and ANCA-mediated aspects of EGPA pathogenesis. Finally, we review the rationale of the currently proposed EGPA dichotomy and future research perspectives.

Treatment of primary systemic necrotizing vasculitides: the role of biotherapies

Treatments of systemic necrotizing vasculitides have progressed markedly over the past few decades. The first attempts to obtain better-adapted therapeutic strategies evaluated the indications of conventional drugs, and their abilities to prolong survival and prevent relapses, while decreasing the severity and number of side effects. The French Vasculitis Study Group, the European Vasculitis Study Group or the Vasculitis Clinical Research Consortium organized most of the prospective clinical trials that have contributed to optimizing targeted treatment strategies. Recent therapeutic strategies include: immunomodulating methods (e.g. plasma exchanges), products (e.g. intravenous immunoglobulins) or, more recently, new agents called biotherapies. Some of the latter, mainly anti-CD20 monoclonal antibodies, have achieved promising effects and are now being evaluated in prospective trials.