Antineutrophil antibodies in inflammatory bowel disease recognize different antigens.

Anti-neutrophil cytoplasmic antibodies (ANCA) were observed in 31 out of 68 sera (45%) from Ulcerative Colitis (UC) patients and in 13 out of 38 Crohn's Disease (CD) sera (34%). The presence of ANCA was not related to disease activity, nor to the localization of the disease manifestations. By Western Blotting ANCA showed reactivity with either lactoferrin, polypeptides occurring as a doublet of 66/67 kD MW, or polypeptides occurring as a doublet of 63/54 kD MW.