Incidence and Specificity of p-ANCA in Rheumatic Diseases

Abstract

Anti-neutrophil cytoplasmic antibodies (ANCA) are an important diagnostic tool for vasculitic diseases. It is established that cANCA are a highly specific marker for Wegener’s granulomatosis and cANCA titers are useful in monitoring disease activity. The significance of pANCA is at present not fully clear: it is mainly found in renal vasculitis but also in inflammatory bowel disease. Recently, pANCA have been described in rheumatic diseases such as SLE (Ref.1) and giant cell arteriitis (Ref.2) amongst others. The target antigens of pANCA are not fully identified, although in the majority of pANCA positive renal vasculitis cases the target antigen is myeloperoxidase (MPO). Furthermore, it is unknown if ANCA play a pathogenetically relevant role in rheumatic diseases and if the presence of ANCA indicates extra-articular involvement such as vasculitis. The aim of this study was to screen a large number of rheumatic diseases in order to assess the incidence and specificity of pANCA in rheumatic diseases.