DIAGNOSTIC-ACCURACY OF SEROLOGICAL ASSAYS IN PEDIATRIC INFLAMMATORY BOWEL-DISEASE

Background & Aims:Accurate serological assays are desirable for the di agnosis of inflammatory bowel disease (IBD) types in the pediatric age group. The aim of this study was to test the diagnostic accuracy of m odified assays for perinuclear (p) antineutrophil cytoplasmic antibodi es (ANCAs) and anti-Saccharomyces cerevisiae antibodies (ASCAs) in pat ients with pediatric ulcerative colitis (UC) and Crohn's disease (CD) and in those without IBD. Methods: With observers blinded to patients' diagnoses, serum specimens were analyzed for immunoglobulin (Ig) A an d IgG ASCAs and ANCAs by enzyme-linked immunosorbent assay. The perinu clear location of ANCAs visualized by indirect immunofluorescence was confirmed by its disappearance after administration of deoxyribonuclea se. Results: IgA and IgG ASCA titers were significantly greater and hi ghly specific for CD (95% for either, 100% if both positive). pANCA wa s 92% specific for UC and absent in all non-IBD controls. The majority of patients with CD positive for pANCA had a UC-like presentation. Di sease location, duration, activity, complications, and treatment with immunosuppressive drugs did not have an impact on the ASCA or pANCA as say results, After resection, UC patients remained pANCA positive, in contrast to patients with CD, in whom ASCA titers decreased toward nor mal values postoperatively, Conclusions: ASCA and pANCA assays are hig hly disease specific for CD and UC, respectively. These serological te sts can assist clinicians in diagnosing and categorizing patients with IBD and may be useful in making therapeutic decisions.