PREVALENCE AND CHARACTERIZATION OF PERINUCLEAR ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES (P-ANCA) DIRECTED AGAINST HMG1 AND HMG2 IN ULCERATIVE-COLITIS (UC)

In a previous study, we reported that the high mobility group (HMG) no n-histone chromosomal proteins HMG1 and HMG2 were novel target antigen s of P-ANCA. In this study, we determined the immunodiagnostic value o f anti-HMG1/HMG2 antibodies in patients with UC. Sixty sera from patie nts with UC were tested for reactivity with HMG1 and HMG2 by means of ELISA. Anti-HMG1 antibody was detected in 32% of patients (40% of P-AN CA(+) patients). Anti-HMG2 antibody was detected in 33% (40% of P-ANCA (+) patients). Thirty-five percent of sera were positive for antibody to either HMG1 or HMG2 (43% of P-ANCA(+) patients). P-ANCA(+) patients expressed anti-HMG1/HMG2 antibodies with significantly greater freque ncy compared with P-ANCA(-) patients. Furthermore, the anti-HMG1/HMG2 antibodies were significantly related to disease activity in UC. Sixte en of the 18 UC patients, who had high titres of anti-HMG1 or -HMG2 an tibody during the active phase, showed lower titres in the inactive ph ase. Anti-HMG1/HMG2 antibodies appear to be useful as a marker for dis ease in UC.