PERINUCLEAR ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES IN PATIENTS WITH CROHNS-DISEASE DEFINE A CLINICAL SUBGROUP

Background & Aims: Antineutrophil cytoplasmic antibodies (ANCA) have b een consistently detected in a subgroup of patients with Crohn's disea se (CD). This study was designed to determine whether serum ANCA expre ssion in patients with CD characterizes an identifiable clinical subgr oup. Methods: The study population consisted of 69 consecutive patient s with an established diagnosis of CD as determined by a combination o f characteristic clinical, radiographic, endoscopic, and histopatholog ic criteria. Sera from the patients were analyzed for the presence of ANCAs using the fixed neutrophil enzyme-linked immunosorbent assay (EL ISA) assay. Perinuclear ANCA (pANCA)-positive and cytoplasmic ANCA (cA NCA)-positive results by ELISA were confirmed by indirect immunofluore scence staining. Clinical profiles of the ANCA-positive patients with CD were compared with those of patients with CD not expressing ANCA (A NCA-negative). Results: pANCA-positive patients with CD have endoscopi cally and/or histopathologically documented left-sided colitis and sym ptoms of left-sided colonic inflammation, clinically reflected by rect al bleeding and mucus discharge, urgency, and treatment with topical a gents. One hundred percent of patients with CD expressing pANCA had '' UC-like'' features. Conclusions: In patients with CD, serum pANCA expr ession characterizes a UC-like clinical phenotype. Stratification of C D by serum pANCA provides evidence of heterogeneity within CD and sugg ests a common intestinal mucosal inflammatory process among a definabl e subgroup of patients with CD and UC expressing this marker.