The fluorescent immunosorbent test for IgG gliadin antibodies and the leucocyte migration inhibition test in coeliac disease; comparison of diagnostic value.

The diagnostic value of the fluorescent immunosorbent test for IgG gliadin antibodies (FIST) has been investigated in comparison with the LIF test--the competence of the gluten subfractions B2 and B3 in releasing lymphokines from peripheral lymphocytes in vitro--in 96 patients with coeliac disease (CD) under various dietary conditions. In untreated children with CD during their first 2 years of life, the FIST showed 100% sensitivity with 95% specificity, whilst the LIF test showed only 70% sensitivity and 73% specificity. Therefore it can be concluded that the FIST as a screening test is superior to the LIF. In older children with a proved recurrence of the mucosal abnormality after reintroduction of a normal diet, only 44% showed increased IgG gliadin antibody titres whereas 70% proved to be positive in the LIF test. Under a controlled gluten challenge all six patients reacted with a distinct increase in gliadin antibody titres whereas the LIF test changed from positive to negative and vice versa without following any clear principle. These results emphasize the inadequacy of the LIF test as a diagnostic method, both in untreated CD and under controlled gluten challenge.