Is High Tissue Transglutaminase Antibody Titers Enough to Diagnose Celiac Disease in Children?


Background. The current standard method for diagnosis of celiac disease (CD) is an adequate small-bowel biopsy (usually obtained through upper gastrointestinal tract endoscopy) showing characteristic histopathological changes, followed by a therapeutic response to a gluten free diet. Commercially available IgA tissue trassglutaminase antibody (TTG) screening tests have been developed with variable sensitivities and specificities. The use of high titer cutoff values than currently recommended should improve the specificity of the test and its positive predictive value.
Objectives. To evaluate the significance of high TTG titers in the diagnosis of CD.
Methods. One hundred sixteen patients with signs and symptoms suggestive of CD had undergone TTG testings (IgA &IgG class) and small-bowel biopsies while 50 healthy volunteers without family history of CD, were sent for TTG testings only. Ten patients excluded from the study because their TTG values and small-bowel biopsies were negative.
Results. Ninety eight of 106 zpatients demonstrated positive biopsy results. Seventy two of 106 patients had IgA TTG levels of >100U/ml, with 70 of 72 exhibiting positive biopsy Results. Twenty two of 28 patients with IgA TTG values >18-100U/ml exhibited positive biopsy results. Six patients with negative IgA TTG levels of ≤18 U/ml had positive biopsies and positive IgG TTG levels (>18 U/ml).Two volunteers had positive IgA TTG levels (>18U/ml).The sensitivity and specificity of IgA TTG were 94.3% and 96% respectively while the sensitivity of duodenal biopsy was 92.6%(8 symptomatic patients had negative small-bowel biopsy while their IgA TTG values were positive).
Conclusions. Symptomatic patients with high titer TTG levels >100 U/ml can be treated as CD without small-bowel biopsy and a negative biopsy does not exclude CD.
Key words. Celiac Disease; Tissue Transglutaminase Antibody; Small-Bowel Biopsy.
Abbreviations. CD, Celiac Disease; TTG, Tissue Transglutaminase Antibody.