Inflammatory bowel disease serology in Asia and the West

AIM:To study serological antibodies in Caucasians and Asians,in health and inflammatory bowel disease(IBD),in Australia and Hong Kong(HK).METHODS:Anti-glycan antibodies[anti-chitobioside(ACCA),anti-laminaribioside(ALCA)],and anti-mannobioside(AMCA),anti-Saccharomyces cervisiae(gASCA);and atypical perinuclear anti-neutrophil cytoplasmic antibody(pANCA)were tested in IBD patients,their unaffected relatives,and healthy controls in Australia and HK(China).Antibody status(positive or negative)and titre was compared between subjects of different geography,ethnicity and disease state.RESULTS:Ninety subjects were evaluated:21 Crohn’s disease(CD),32 ulcerative colitis(UC),29 healthy controls,and 8 IBD patient relatives.Forty eight subjects were Australian(29 Caucasian and 19 ethnic Han Chinese)and 42 were from HK(all Han Chinese).Caucasian CD patients had a significantly higher antibody prevalence of gASCA(67%vs 3%,P<0.001),ALCA(44%vs 6%,P=0.005),and AMCA(67%vs 15%,P=0.002),whereas HK CD patients had a higher prevalence of only AMCA(58%vs 25%,P=0.035),when compared with UC and healthy subjects in both countries.Caucasian CD had significantly higher gASCA prevalence(67%vs 0%,P<0.001)and titre(median59 vs 9,P=0.002)than HK CD patients.Prevalence and titres of ALCA,ACCA and AMCA did not differ between CD in the two countries.Presence of at least one antibody was higher in Caucasian than HK CD patients(100%vs 58%,P=0.045).pANCA did not differ between countries or ethnicity.CONCLUSION:Serologic CD responses differ between HK Asian and Australian Caucasian patients.Different genetic,environmental or disease pathogenic factors may account for these differences.

New serological biomarkers of inflammatory bowel disease

Serological biomarkers in inflammatory bowel disease (IBD) are a rapidly expanding list of non-invasive tests for objective assessments of disease activity, early diagnosis, prognosis evaluation and surveillance. This review summarizes both old and new biomarkers in IBD, but focuses on the development and character-ization of new serological biomarkers (identifi ed since 2007). These include fi ve new anti-glycan antibodies, anti-chitobioside IgA (ACCA), anti-laminaribioside IgG (ALCA), anti-manobioside IgG (AMCA), and antibod-ies against chemically synthesized (∑) two major oligomannose epitopes, Man α-1,3 Man α-1,2 Man (∑Man3) and Man α-1,3 Man α-1,2 Man α-1,2 Man (∑Man4). These new biomarkers serve as valuable complementary tools to existing biomarkers not only in differentiating Crohn's disease (CD), ulcerative colitis (UC), normal and other non-IBD gut diseases, but also in predicting disease involvement (ileum vs colon), IBD risk (as subclinical biomarkers), and disease course (risk of complication and surgery). Interestingly, the prevalence of the antiglycan antibodies, including anti-Saccharomyces cerevisiae antibodies (ASCA), ALCA and AMCA, was found to be associated with single nucleotide polymorphisms (SNPs) of IBD susceptible genes such as NOD2/CARD15, NOD1/CARD4, toll-likereceptors (TLR) 2 and 4, and β-defensin-1. Further-more, a gene dosage effect was observed: anti-glycan positivity became more frequent as the number of NOD2/CARD15 SNPS increased. Other new serum/ plasma IBD biomarkers reviewed include ubiquitination factor E4A (UBE4A), CXCL16 (a chemokine), resistin, and apolipoprotein A-IV. This review also discusses the most recent studies in IBD biomarker discovery by the application of new technologies such as proteomics, fourier transform near-infrared spectroscopy, and mul-tiplex enzyme-linked immunosorbent assay (ELISA)'s (with an emphasis on cytokine/chemokine profiling). Finally, the prospects of developing more clinically use-ful novel diagnostic algorithms by incorporating new technologies in serological biomarker profiling and integrating multiple biomarkers with bioinformatics analysis/modeling are also discussed.