Anti-neutrophil cytoplasmic antibodies (ANCA) in ulcerative colitis: anti-cathepsin G and a novel antibody correlate with a refractory type

Abstract

SUMMARYWe analysed the clinical significance of ANCA in patients with ulcerative colitis. On either an indirect immunofluorescence assay or an ELISA with fixed neutrophils, 71% (25/35) of the patients were positive for ANCA. However, only half of them reacted with either cathepsin G or lactoferrin. Western blot assays revealed positive bands in 40% (10/25) of the antibody-positive patients. The sizes of the bands detected were 58, 47, 44, 40, and 28 kD. No significant correlation was found between the ANCA positivity and various variables, i.e. disease activity, extent of lesion, or treatment of the disease. The anti-cathepsin G and 28-kD positivity, however, significantly correlated with a refractory type of ulcerative colitis.

Autoantibodies pANCA, GAB and PAB in inflammatory bowel disease: prevalence, characteristics and diagnostic value

“…Th ese autoantigens are thought to be located not only in the cytoplasm of the granulocyte but also inside the granulocyte nucleus (histone 1, nonhistone chromosomal protein, high mobility group) [17,[27][28][29][30][31], with exhibited sensitivity on DNA-se treatment [17,27]. In agreement with the fi ndings of some other investigators [32][33][34], we found a positive reaction with cathepsin-G in two cases of UC; however, this specifi city was not signifi cantly diff erent from the control group, where two samples also tested positive with cathepsin-G. In our study we have confi rmed the previously reported specifi city of PAB for CD [18,35] and found PAB only among the patients with CD, but with a low prevalence (30%), comparable with the prevalences (26-39%) reported by other investigators [18,[35][36][37].…”

Novel autoantigens of perinuclear anti-neutrophil cytoplasmic antibodies (P-ANCA) in ulcerative colitis: non-histone chromosomal proteins, HMG1 and HMG2

“…Thus, it appeared that an antibody against neutrophil 28-kD antigen serves as a predictive marker of refractory UC. Although the molecular size of the 28-kD protein was similar to that of cathepsin G, we proved that they were distinct from each other [9]. Here, we report the purification and identification of this protein.…”

“…Considering that previously identified P-ANCA in UC do not correlate with disease activity, duration, extent, or treatment [2,3,9], anti-HMG1/2 antibodies might become important in the serological diagnosis of refractory UC. It is also interesting that anti-HMG1/2 and anti-cathepsin G antibodies co-developed in patients with refractory UC [9]. To investigate the disease specificity of anti-HMG1/2 antibodies, screening of the antibodies by ELISA using HMG1 and HMG2 is underway.…”

“…Five of them suffered from refractory type UC. The refractory type was defined according to the previous report [9].…”

“…P-ANCA pattern is detected in 30-83% of sera from patients with ulcerative colitis (UC) [2][3][4][5][6], and some of the antigens associated with P-ANCA have been shown to be lactoferrin and cathepsin G [7,8]. In our previous study, we tested ANCA from sera of 35 UC patients [9]. Twenty-two sera were positive for P-ANCA by IIF.…”