Original Contribution
The American Journal of Gastroenterology (2004) 99, 2186–2194; doi:10.1111/j.1572-0241.2004.40486.x
A Prospective Comparative Study of ASCA and pANCA in Chinese and Caucasian IBD Patients
Ian Craig Lawrance MD, PhD1, Kevin Murray BSc, (Hons), MSc1, Anne Hall BAppl Sc, Post Grad Dip Bio Sci1, Joseph J Y Sung MD, PhD1 and Rupert Leong MD1
1Department of Gastroenterology, University Department of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, WA, Australia; Statistical Consulting Group, School of Mathematics and Statistics (M019), University of Western Australia, Australia; Department of Immunology, Fremantle Hospital, WA, Australia; Department of Medicine and Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China; and Department of Gastroenterology, Faculty of Medicine, University of New South Wales, Bankstown-Lidcombe Hospital, Sydney, NSW, Australia
Correspondence: Ian Craig Lawrance, The School of Medicine and Pharmacology, University of Western Australia, T Block, Fremantle Hospital, Alma Street, Fremantle, 6059, WA, Australia
Received 25 May 2004; Revised 0000; Accepted 9 June 2004.
Abstract
BACKGROUND
Inflammatory bowel disease manifests throughout all ethnic groups. Antisaccharomyces cerevisiae (ASCA) and antineutrophil cytoplasmic antibodies (pANCA) can aid in the differentiation between Crohn's disease (CD) and ulcerative colitis (UC), but their sensitivity may vary between races.
OBJECTIVES
This study compared the sensitivity, specificity, and positive and negative predictive values (PPV, NPV) of pANCA and ASCA between Chinese and Caucasian IBD populations and identified disease subtype associations.
RESULTS
Three hundred patients were prospectively recruited from Caucasian and Chinese populations (CD, n = 50, UC, n = 50, controls, n = 50 each). pANCA detection was greater in Caucasian than Chinese UC patients (p= 0.046). ASCA IgG detection was similar, but IgA was lower in Chinese CD patients (p < 0.001). Differentiation between UC and CD (+ve pANCA/-ve ASCA) demonstrated a PPV of 92% in isolated colonic disease. Logistic regression in CD identified positive pANCA had a lower association with ileal (OR = 6.8, p= 0.0067) and complicated disease (OR = 5.5, p= 0.015). Caucasian CD patients with positive ASCA IgA/IgG had a greater association with ileal (OR = 6.7, p= 0.022) or complicated disease (OR = 9.4, p= 0.0073) and in Chinese CD patients positive ASCA IgA/IgG was associated with isolated ileal disease (OR = 16.8, p= 0.032). Linear regression demonstrated that higher ASCA titers predicted complicated CD and isolated ileal disease.
CONCLUSIONS
This study identified that pANCA is more sensitive in Caucasian than Chinese UC and that ASCA IgA has a low yield in Chinese CD. pANCA and ASCA are useful for differentiating between UC and CD in both populations, and ASCA IgG and IgA titers have potential use in determining the risk of developing complicated CD.
