394 Age of Diagnosis Influences Serologic Responses in Children with Crohn Disease: A Possible Clue to Etiology?

Abstract

Direct all correspondence to: James Markowitz, MD, Schneider Children's Hospital, 269-01 76 Ave, New Hyde Park, NY 11040, Phone: 718-470-3430, Fax: 718-962-2908 Crohn disease (CD) is often associated with antibodies to microbial antigens. Differences in immune response may offer clues to the pathogenesis of the disease.AIM-To examine the influence of age at diagnosis on serologic response in children with CD.METHODS-Data were drawn from 3 North American multicenter pediatric IBD research consortia. At or shortly after diagnosis, pANCA, ASCA IgA, ASCA IgG, anti-ompC and antiCBir1 were assayed. Results were compared as a function of age at CD diagnosis (0-7 years vs 8-15 years).RESULTS-705 children (79 <8 yr of age at diagnosis, 626 ≥8yr) were studied. Small bowel CD was less frequent in the younger group (48.7% vs 72.6%; p<0.0001) while colonic involvement was comparable (91.0% vs 86.5%). ASCA IgA and IgG were seen in <20% of those 0-7 yr compared to nearly 40% of those 8-15 yr (p<0.001), while anti-CBir1 was more frequent in the younger children (66% vs 54%, p<0.05). Anti-CBir1 detected a significant number of children in both age groups who otherwise were serologically negative. Both age at diagnosis and site of CD involvement were independently associated with expression of ASCA and anti-CBir1.CONCLUSIONS-Compared to children 8-15 yr of age at diagnosis, those 0-7 yr are more likely to express anti-CBir1 but only half as likely to express ASCA. These age-associated differences in antimicrobial seropositivity suggest that there may be different, and as yet unrecognized, genetic, immunologic and/or microbial factors leading to CD in the youngest children.

Classical Serological Markers in Pediatric Inflammatory Bowel Disease in Brazil

“…On the other hand, Markowitz et al founded ASCA IgA and IgG in their patients less than 20% of those 0-7 years compared to nearly 40% of those 8-15 years (P<0.001). By contrast, older age at diagnosis and small bowel CD independently increased the risk of ASCA IgA and IgG expression (27) .…”

“…The other aspects we should take into consideration for these differences in the results ranges include an individual serological response to various microbial and autoantigens that can develop in IBD, the loss of mucosal immune tolerance, an increased mucosa permeability, influenced by several distinct genetic determinants and or environmental exposure across various geographic regions, age at diagnosis and the time of the sample at diagnosis or during the follow-up of the disease (12,26,27) .…”

“…Our study founded the accuracy of ASCA IgG and ASCA IgA testing for the detection of CD the sensitivity of 34.7% and 32.7%, the specificity of 100% and 89.6%, and negative predictive value of 60% and 56.6% respectively. In pediatric IBD, sensitivity/ specificity of ASCA in CD range between 35% to 76% and 88% to 95%, respectively (12,14,(24)(25)(26)(27) .…”