The association of transient IgM PR3-ANCA with an acute respiratory manifestation of AAV suggests a possible link between an infectious trigger and AAV disease activity.
C3c was found in 78 of 187 renal biopsies (41.7%) divided over 32.3% of proteinase-3 (PR3)-AAV patients and 52.3% of myeloperoxidase (MPO)-AAV patients (P = 0.006), whereas C3d was found positive in 51.1% of PR3-AAV patients and 70.4% of MPO-AAV patients (P = 0.105).
Alpha-1 anti-trypsin is the physiological inhibitor of PR3 and carriage of the defective allele PI*Z was observed as the first genetic risk factor for the development of PR3-ANCA-associated vasculitis.
ANCA-associated vasculitis(AAV) covers a group of systemic necrotising vasculitides characterised by inflammation of small vessels, sometimes with granuloma, and associated with autoantibodies to neutrophil cytoplasmic proteases (proteinase-3 or myeloperoxidase).
This study confirms that the pathogenesis of ANCA-associated vasculitis has a genetic component, shows genetic distinctions between granulomatosis with polyangiitis and microscopic polyangiitis that are associated with ANCA specificity, and suggests that the response against the autoantigen proteinase 3 is a central pathogenic feature of proteinase 3ANCA-associated vasculitis.