Celiac antibodies in children with type 1 diabetes - A diagnostic validation study.

Introduction: Autoimmune diseases, such as celiac disease (CD) and diabetes mellitus type 1, tend to co-occur within the same patient. The prevalence of CD in diabetic children is higher than in the general population, and is estimated to be 0.6-16.4%. The diagnosis of CD is based on histopathological examination and serological testing, however, these methods are still imperfect and new diagnostic algorithms should be considered.Aim: The aim of the study was to assess the diagnostic value of serological tests detecting antibodies against deamidated gliadin peptide, endomysium, tissue transglutaminase, neo-epitope tissue transglutaminase and to identify HLA-related genetic predisposition to CD in patients with type 1 diabetes mellitus (DM1).Methods: Autoantibodies were measured in the sera of 392 children suffering from DM1 aged 1-19years old (mean 11.764.14years old). Additionally, PCR-based assessment of HLA DQ2/DQ8 genotyping was performed.Results: A positive result of at least one serological test was obtained from 81 children (20.66%). The sensitivity and specificity were 76.47% and 91.67% for anti-DGP IgA, 70.59% and 58.33% for IgG anti-DGP, respectively. A positive predictive value was 100% for the anti-TG IgA at cutoff levels of 5 and 10 times higher than upper limit of reference values. HLA DQ2 and/or DQ8 were found in 97.6% of examined children.Conclusions: Tests based on anti-TG IgA are more accurate for detecting CD in children with type 1 diabetes than anti-DGP IgA. A high percentage of diabetic children carry HLA alleles predisposing to CD, which indicates that genetic screening in this group of patients is not obligated.