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. There was no correlation to therapy, activity, sex, age, extent and duration of disease. Moreover, the sera did not exhibit significant reactivity in ELISAs testing for Cathepsin G-, Lactoferrin-, Myeloperoxidase-, Elastase- or Proteinase 3- specificity.