Background: Serum anti-actin IgA antibodies (AAA) were identified in patients with celiac disease (CD), and a close correlation emerged between the presence of AAA and mucosa damage, but test for AAA found in celiacs have a wide range of sensitivity and specificity values.
Aim: To compare 1) the sensitivity and specificity of untreated, calcium-chelated and heated sera from 102 celiacs, 52 sick patients and 103 healthy controls in the determination of AAA, and 2) the reliability of AAA with anti-transglutaminase antibodies (anti-tTG) in diagnosing celiac disease and in predicting intestinal damage. The intestinal derived AAA was isolated by using the phage-display library technique.
Results: Treated sera was significantly more sensitive than untreated (p=0.0001), and showed a significant correlation between AAA and the three degrees (3a, 3b, 3c) of intestinal damage (p=0.01). Sensitivity and specificity values of anti-tTG assay were higher than the AAA assay, and anti-tTG serum-concentration was only significantly correlated with more severe (3b and 3c) intestinal damage degrees. AAA isolated by phage display showed similar results of serum AAA in immunofluorescence assay.
Conclusions: Notwithstanding correlation between AAA and celiac disease, AAA assay, also after treatments, has little to offer in screening for CD compared to the well-established anti-transglutaminase assay.