Bulb biopsies for diagnosing celiac disease in children: A prospective multicenter study using quantitative histomorphometry

Abstract

Objectives: Duodenal bulb specimens are recommended for the diagnostic evaluation of celiac disease (CeD). However, it remains unclear if their quality and histomorphometry measures are comparable to samples obtained from the distal duodenum. We investigated this issue, as well as the diagnostic applicability of morphometry and advanced immunohistochemistry methods, in a prospective pediatric cohort using validated morphometric readouts. Methods: One hundred ninety-four children with CeD autoantibodies underwent systematic sampling at diagnosis from bulb and distal duodenum. Morphometric evaluation included measurements of villous height (VH), crypt depth (CrD), and VH:CrD. Mucosal CD3+ and γδ+ intraepithelial lymphocytes (IEL) densities and transglutaminase-2-targeted immunoglobulin A (IgA) deposits were measured from frozen biopsies. Sixteen seronegative non-CeD children served as controls. Result: Bulb specimens were frequently of inadequate quality, with paired comparisons to distal samples feasible in only 112 patients. Mean VH and VH:CrD were lower in the bulb than in the distal duodenum (168 vs. 239 μm, p < 0.001; 0.73 vs. 1.01, p = 0.027, respectively), while CrDs and IEL densities were comparable. Twelve patients had reduced VH:CrD consistent with CeD in the bulb only. Eight seropositive children exhibited normal VH:CrD in both bulb and distal duodenal samples, but the presence of positive γδ + IELs and IgA deposits indicated incipient CeD. Overall, 96.4% of the patients and none of the controls had IgA deposits in both bulb and distal samples. Conclusions: A subgroup of patients had diagnostic lesions only in the bulb, but discretion is needed, as these specimens may be of poorer quality and different histomorphometric measurements compared to distal samples. The determination of IgA deposits is valuable at both duodenal sites. Trial Registration: This study is registered at ClinicalTrials.gov (registration number NCT02072590). The study was registered in February 2014, while patient enrollment began in January 2012. At the time of study initiation, mandatory prospective trial registration was not yet widely enforced for nonpharmaceutical, investigator-initiated clinical studies.