p-ANCA as a diagnostic marker in ulcerative colitis.

P-ANCA that do not react with myeloperoxidase (MPO) have been claimed to serve as a useful diagnostic marker in the differential diagnosis of inflammatory bowel disease (IBD). Therefore, in this study we determined the frequency of MPO-negative-p-ANCA in patients with inflammatory bowel disease and correlated the presence with intestinal and extra-intestinal disease manifestation. In 44 out of 65 (68%) sera from patients with ulcerative colitis (UC) but in only 14 of 66 (21%) with Crohn's disease (CD) MPO-negative-p-ANCA were detected whereby colonic involvement and extraintestinal manifestations seemed to be important.