ANCA-associated vasculitis in children.

Abstract

Childhood-onset anti-neutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAVs) are a group of systemic autoimmune disorders characterized by inflammatory cells infiltration, necrosis of small-medium blood vessels and autoantibodies to the neutrophil proteins leukocyte proteinase 3 (PR3-ANCA) or myeloperoxidase (MPO-ANCA). Primary AAVs in children are rare with a higher female preponderance, a peak age at onset in the second decade and median age at diagnosis 12–14 years [1]. They are classified into [2] granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (EGPA) and renal-limited AAVs (Fig. 1). GPA, the estimated incidence of which in Europe is less than 1 per 2 million population/year, is more common than MPA and EGPA but recently literature demonstrated that MPA was more frequent than GPA in children [3]. ... AAVs may be primary or secondary. Several factors may have a role: ... Patients present general symptoms such as weight loss, poor feeding and fever preceding systemic manifestations. Localized forms affecting single organs may lead to delayed diagnoses. There is an overlap in clinical features of GPA and MPA since both may present a high incidence of gastrointestinal manifestations (chronic nausea, diarrhea, abdominal pain), muco-cutaneous manifestations (oral and genital ulcers, palpable purpura, petechial rash, livedo, subcutaneous nodules) and musculoskeletal manifestations (arthralgia, myalgia, arthritis). MPA can be distinguished from GPA clinically by the lack of granulomatous manifestations and serologically by its more frequent association with MPO-ANCA. Both EGPA and GPA are characterized by granulomatous inflammation and necrotizing vasculitis involving small- and medium-sized vessels, but EGPA is distinguished from GPA by eosinophilia and asthma.