Adult-onset Henoch-Schonlein purpura with positive c-ANCA (anti-proteinase 3): Case report and review of literature

摘要

Anti-neutrophil cytoplasmic antibodies (ANCA) have two common patterns detected by indirect immunofluorescence test (IIF test). The cytoplasmic pattern (c-ANCA) that is strongly associated with antibodies against proteinase-3 (PR3) and the perinuclear pattern (p-ANCA) that is mostly directed against myeloperoxidase (MPO). Anti-proteinase 3 and anti-MPO are characteristic for pauci-immune small vessel vasculitis like Wegener's granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome and idio-pathic crescentic glomerulonephritis. In Wegener's granulomatosis (WG), the combination of c-ANCA with anti-PR3 antibodies has a sensitivity of 58% and a specificity of 99%. On the other hand, the presence of c-ANCA (anti-PR3) in immune-complex-mediated vasculitis such as Henoch-Schonlein purpura (HSP) is very unusual. We report a case of biopsy proven HSP associated with IgG c-ANCA (anti-PR3).