Abstract
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) [1]. 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 [2]. 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% [3]. 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. References Kallenberg CG, Heeringa P, Stegeman CA: Mechanisms of disease: pathogenesis and treatment of ANCA-associated vasculitis. Nat Clin Pract Rheumatol 2006, 2:661–670. van der Woude FJ, Rasmussen N, Lobatto S et al. Autoantibodies against neutrophils and monocytes: tool for diagnosis and marker of disease activity in Wegener’s granulomatosis. Lancet 1985; 1:425-429. Specks U, Wheatley CL, McDonald TJ et al. Anticytoplasmic autoantibodies in the diagnosis and follow up of Wegener’s granulomatosis. Mayo Clin Proc 1989; 64: 28–36. Disclosure of Interest None Declared