CATALASE AND ALPHA-ENOLASE - 2 NOVEL GRANULOCYTE AUTOANTIGENS IN INFLAMMATORY BOWEL-DISEASE (IBD)

In IBD, the target antigens of anti-neutrophil cytoplasmic autoantibod ies (ANCA) have not been fully identified, which limits the analysis o f the diagnostic significance as well as of the possible pathophysiolo gical role of these antibodies. In this study, we identify the target antigens of ANCA in large groups of patients with ulcerative colitis ( UC) and Crohn's disease (CD). Apart from antibodies against lactoferri n and bactericidal/permeability-increasing protein (BPI), which have b een reported before, antibodies against two novel granulocyte antigens were identified: antibodies against a 57/56-kD doublet were found in 38% of samples from UC patients and in 26% of samples from CD patients , whereas antibodies against a 47-kD protein were found in 10% of samp les from UC patients and in 18% of samples from CD patients. Partial p urification and amino acid sequence analysis identified the 57-kD prot ein as catalase and the 47-kD protein as alpha-enolase. This study is the first to report catalase and alpha-enolase as granulocyte antigens for autoantibodies in IBD.