Celiac disease in Tunisia: serological screening in healthy blood donors.

BACKGROUND: Recent epidemiological studies in Europe and in USA using antigliadin antibodies and antiendomysium antibodies for initial screening have shown that the overall prevalence of celiac disease (CD) is about 1:200 (0.5%). AIM: To screen for CD in healthy blood donors in Tunisia. PATIENTS AND METHODS: Sera from 2500 healthy blood donors (median age: 21 years, 70% men and 30% women) were screened for IgG-antigliadin antibodies and IgA-antigliadin antibodies with an enzyme-linked immunosorbent assay. All sera with positive antigliadin antibodies were tested for antiendomysium antibodies using human umbilical cord cryosections as substrate. RESULTS: Seven healthy blood donors (median age: 21 years; four men, three women) have antiendomysium antibodies. The prevalence of antiendomysium antibodies in healthy blood donors in Tunisia is 1:355 (0.28%). CONCLUSIONS: On the basis of a high specificity of the antiendomysium antibodies, it is likely that the seven blood donors identified in this study have CD. These data suggest that CD is frequent in Tunisia.

Tissue transglutaminase antibodies in celiac disease, comparison of an enzyme linked immunosorbent assay and a dot blot assay.

AIMS: The purpose of our study is to determine the sensitivity, specificity and predictive values of an enzyme linked immunosorbent assay (ELISA) and a dot blot assay for the detection of IgA class anti-tissue transglutaminase antibodies (IgA-AtTGA) and to compare these results with those of IgA class anti-endomysium antibodies (IgA-AEA), IgA class anti-reticulin antibodies (IgA-ARA) and IgA class anti-gliadin antibodies (IgA-AGA). PATIENTS: Serum samples from 143 patients (97 children, 46 adults) with untreated celiac disease (CD) confirmed by intestinal biopsy and 74 disease controls (64 children, 10 adults) were studied. Methods. - The anti-tissue transglutaminase antibodies were detected by dot blot assay and an ELISA using guinea pig tissue transglutaminase (gp-tTG) as antigen. The anti-endomysium antibodies were detected by an indirect immunofluorescence technique on cryostat sections of human umbilical cord. The anti-reticulin antibodies were also investigated by indirect immunofluorescence on cryostat sections of kidney, liver and stomach of rat. The anti-gliadin antibodies were determined by an ELISA. RESULTS: The sensitivity of an ELISA for the detection of anti-tissue transglutaminase antibodies was 86% in children and 87% in adults and the sensitivity of dot blot assay was 57% in children and 54% in adults. The specificity of an ELISA and dot blot for the detection for anti-tissue transglutaminase antibodies was, respectively, 96% and 88% lower than that of anti-endomysium antibodies (100%). The sensitivity of anti-gliadin antibodies was 97% in children and 91% in adults and their specificity was 85%. The sensitivity of anti-reticulin antibodies was 94% in children and 87% in adults. Their specificity was 100%. CONCLUSIONS: The sensitivity and specificity of an ELISA for the detection of anti-tissue transglutaminase antibodies were better than that of dot blot assay. However, this dot blot assay could screen four celiac patients who have not had anti-tissue transglutaminase antibodies by an ELISA. The sensitivity of anti-endomysium antibodies was better than that of anti-tissue transglutaminase antibodies, anti-reticulin antibodies and anti-gliadin antibodies but in children aged less than 2 years, the sensitivity of anti-gliadin antibodies was better than that of anti-tissue transglutaminase antibodies.