Background The antineutrophil cytoplasmic autoantibody (ANCA) - associated vasculitis (AAV) include granulomatosis with polyangitis GPA (Wegener’s), microscopic polyangitis (MPA), allergic granulomatosis and angitis (CSS) (Churg-Strauss syndrome) and renal - limited vasculitis (RLV) . The strong association of proteinase 3 ANCA (PR3 ANCA) / myeloperoxidase ANCA (MPO ANCA) with the AAV has led to assumption that ANCAs are directly involved in the pathogenesis of these diseases . PR3-ANCAs are mainly detected in GPA, whereas MPO-ANCAs are predominantly found in MPA and CSS. In GPA, PR3-ANCA is positive at >90% .
Objectives To study the profile of ANCA in ANCA associated vasculitis (AAV).
Methods A review of ANCA tested patients at KSU clinics, Riyadh, Saudi Arabia during the period 1980-2012.
Results Out of 459 patients tested for ANCA, 330(71.9%) were positive for ANCA. Patterns were: P-ANCA in 167 (36.4 %), C-ANCA in 103 (22.4%) and Atypical in 60(13.1%). Among these 459 ANCA tested patients, Twenty three cases of ANCA associated vasculitis (AAV) were identified. The diagnoses in these 23 cases were: GPA in 16/23(69.6%), CSS in 5/23(21.7%) and MPA in 2/23(8.7%) cases. With regard to 16 GPA cases, the results showed that 14 (87.5%) were ANCA positive and 2 (12.5%) were ANCA negative. Pattern of ANCA was C- ANCA in 11 (68.75 %) and P- ANCA in 3 (18.75 %). Ten of the 16 GPA cases were analyzed for MPO and PR3 specificity. None showed specificity for MPO, while 8 (80.0%) showed PR3 specificity and 2 were without PR3 specificity.
Conclusions In all ANCA tested patients for various diagnoses, P-ANCA (36.4%) was more frequent compared to C-ANCA. However GPAwas the most common vasculitis[16/23 (69.6%)]. We found that 87.5 % of GPA cases were positive for ANCA, most of them (68.8 %) were C-ANCA positive and mostly (80.0%) showed PR3-ANCA specificity.
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Disclosure of Interest None Declared