Anti-transglutaminase antibody assay of the culture medium of intestinal biopsy specimens can improve the accuracy of celiac disease diagnosis.

BACKGROUND We measured anti-transglutaminase (anti-tTG) antibody in the culture medium of intestinal biopsy specimens from patients with suspected celiac disease (CD) and evaluated the relationship between antibody production and severity of intestinal mucosal damage. METHODS We performed diagnostic testing for CD on 273 consecutive patients. In addition to routine histologic evaluation of duodenal biopsy specimens, we assayed anti-tTG antibodies in serum and in the culture medium of duodenal biopsy specimens. RESULTS CD was diagnosed in 191 of the 273 patients. Sensitivity and specificity of the serum anti-endomysium (EmA) and anti-tTG assays were 83% and 85% and 99% and 95%, respectively, and both had 88% diagnostic accuracy. EmA and anti-tTG assayed in the culture medium had 98% sensitivity, 100% specificity, and 98% diagnostic accuracy (vs serum assays; P <0.0001). Twenty-nine CD patient specimens (16%) were negative for serum anti-tTG and EmA; for 24 of these patients, anti-tTG assay of the culture medium was positive. The CD patients whose biopsy specimens were positive for serum antibodies showed the following intestinal histologies: total villous atrophy, 35%; severe villous atrophy, 25%; mild atrophy, 25%; villi with no atrophy but with increased intraepithelial lymphocytes, 15%. None of the CD patients whose specimens were negative for serum antibodies showed total or severe villous atrophy; 77% had mild villous atrophy, and 23% had no villous atrophy but had increased intraepithelial lymphocyte counts. Mild villous atrophy was also seen in specimens from approximately 15% of patients without CD. CONCLUSION Anti-tTG assay of the culture medium of biopsy specimens can improve the accuracy of CD diagnosis in patients negative for serum antibodies.