Tissue transglutaminase levels above 100 U/mL and celiac disease:A prospective study

摘要： AIM:To investigate whether a tissue-transglutaminase antibody(tTGA) level ≥ 100 U/mL is sufficient for the diagnosis of celiac disease(CD).METHODS:Children suspected of having CD were prospectively included in our study between March 2009 and September 2011.All patients with immune globulin A deficiency and all patients on a gluten-free diet were excluded from the study.Anti-endomysium antibodies(EMA) were detected by means of immunofluorescence using sections of distal monkey esophagus(EUROIMMUN,Luebeck,Germany).Serum anti-tTGA were measured by means of enzyme-linked immunosorbent assay using human recombinant tissue transglutaminase(ELiA Celikey IgA kit Phadia AB,Uppsala,Sweden).The histological slides were graded by a single experienced pathologist using the Marsh classification as modified by Oberhuber.Marsh Ⅱ and Ⅲ lesions were considered to be diagnostic for the disease.The positive predictive values(PPVs),negative predictive values(NPVs),sensitivity and specificity of EMA and tTGA along with their 95% CI(for the cut off values > 10 and ≥ 100 U/mL) were calculated using histology as the gold standard for CD.RESULTS:A total of 183 children were included in the study.A total of 70(38.3%) were male,while 113(61.7%) were female.The age range was between 1.0 and 17.6 years,and the mean age was 6.2 years.One hundred twenty(65.6%) patients had a small intestinal biopsy diagnostic for the disease;3 patients had a Marsh Ⅱ lesion,and 117 patients had a Marsh Ⅲ lesion.Of the patients without CD,only 4 patients had a MarshⅠlesion.Of the 183 patients,136 patients were positive for EMA,of whom 20 did not have CD,yielding a PPV for EMA of 85%(95% CI:78%-90%) and a corresponding specificity of 68%(95% CI:55%-79%).The NPV and specificity for EMA were 91%(95% CI:79%-97%) and 97%(95% CI:91%-99%),respectively.Increased levels of tTGA were found in 130 patients,although only 116 patients truly had histological evidence of the disease.The PPV for tTGA was 89%(95% CI:82%-94%),and the corresponding specificity was 78%(95% CI:65%-87%).The NPV and sensitivity were 92%(95% CI:81%-98%) and 97%(95% CI:91%-99%),respectively.A tTGA level ≥ 100 U/mL was found in 87(47.5%) patients,all of whom were also positive for EMA.In all these 87 patients,epithelial lesions confirming CD were found,giving a PPV of 100%(95%CI:95%-100%).The corresponding specificity for this cutoff value was also 100%(95% CI:93%-100%).Within this group,a total of 83 patients had symptoms,at least gastrointestinal and/or growth retardation.Three patients were asymptomatic but were screened because they belonged to a group at risk for CD(diabetes mellitus type 1 or positive family history).The fourth patient who lacked CD-symptoms was detected by coincidence during an endoscopy performed for gastro-intestinal bleeding.CONCLUSION:This study confirms based on prospective data that a small intestinal biopsy is not necessary for the diagnosis of CD in symptomatic patients with tTGA ≥ 100 U/mL. ... （共5頁(yè)）