ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES (ANCA) AND INFLAMMATORY BOWEL DISEASES IN CHINESE

Inflammatory bowel diseases are uncommon in the Chinese, bur the incid ence is rising. Their differentiation from infective colitis is often not clear-cut and diagnosing inflammatory bowel diseases can be diffic ult in Asia. We have studied Chinese patients with ulcerative colitis (N = 19) and Crohn's disease (N = 12) for anti-neutrophil cytoplasmic antibodies (ANCA) by indirect immunofluorescence (IIF) and enzyme-link ed immunosorbent assays (ELISA). Patients with enteric fever (N = 29) and irritable bowel syndrome (N = 24) were recruited as controls. Seve nty-three percent of ulcerative colitis patients exhibited either p-AN CA (31%) or c-ANCA (42%) by IIF. Twenty-Jive percent of Crohn's diseas e patients were found to be p-ANCA positive. However, these ANCA were nonreactive to anti-ct granule, antiproteinase 3, antimyeloperoxidase, or antilactoferrin. All positive patients had extensive colitis. Sera collected from patients suffering from enteric fever and irritable bo wel syndrome were negative for ANCA by IIF and ELISA. We concluded tha t the detection of ANCA is helpful in diagnosing inflammatory bowel di seases. Further attempts to characterize these autoantibodies are need ed.