Clinical Utility of Anti-Tissue Transglutaminase Antibodies for Diagnosis and Monitoring of Coeliac Disease in Children and Adolescents.

UNLABELLED

Identification of tissue transglutaminase (tTG) as a major target antigen of IgA anti-endomysial antibodies and detection of auto-antibodies against tTG in the serum pointed out a new direction in the serologic diagnosis of coeliac disease. Clinical utility of determination of anti-tTGIgA antibodies, with recombinant human tTG used as antigen, was evaluated for the diagnosis of coeliac disease and monitoring the adherence to the diet in children and adolescents.

PATIENTS

The study was performed in 169 patients aged 2-24 years, including 42 children (26 girls, 16 boys, mean age 8.01 ± 5.69, range 2-18) with newly diagnosed coeliac disease (CD) (group I), 60 patients (39 females, 21 males, mean age 15.68 ± 4.74, range 5-24) with CD recognized at least 3 years before entering the study, non-compliants with gluten-free diet (group II) and 67 children (34 girls, 33 boys, mean age 6,28± 4.48, range 2-16) suspected of malabsorption, in whom diagnosis of CD had been excluded.

METHODS

Serum samples were taken from all patients and tested for total IgA, anti-endomysial IgA (IgAEmA) or IgG autoantibodies (IgGEmA), only in cases with IgA deficiency, by indirect immunofluorescence method and anti-tTGIgA antibodies by ELISA.

RESULTS

[Table: see text] Strong significant associations between anti-tTGIgA present in the serum and IgAEmA (Kendall τ 0.7748, p<0.0001) and good correlation between the levels of anti-tTGIgA and IgAEmA (r=0,488, p=0.001) were found in group I. We have not shown the relationship between the presence of both types of antibodies in patients of group II (Kendall τ 0.2102, p=0.0937). However, a good significant correlation between the levels of these parameters was observed (r=0,813, p<0,0001). Anti-tTGIgA concentration was nificantly higher in patients of group I compared to group II (38.35 U/ml v. 23.13 U/ml, p=0,0356). The sensitivity of anti- tTGIgA test in group I was 88.1%, in group II - 91.7% while specificity reached 97%.

CONCLUSIONS

Determination of anti-tTGIgA shows high sensitivity (88.1%) and specificity (97%) for the detection of coeliac disease. This test can be used alternatively with the immunofluorescent IgAEmA in diagnosis of coeliac disease, and also as a marker of compliance with gluten-free diet. However, both IgAEmA and anti-tTGIgA tests do not reach 100% sensitivity and specificity for diagnosis and nitoring of celiac disease. Therefore small intestinal biopsy is still recommended as a ? gold standard?.