Determination of IgG and IgA antibodies against native gliadin is not helpful for the diagnosis of coeliac disease in children up to 2 years old.

ABSTRACT

OBJECTIVE: Assays for antibodies against native gliadin (anti-nGli) are still often assumed to perform better in the diagnosis of coeliac disease in young children than tests for antibodies to deamidated gliadin (anti-dGli), tissue transglutaminase (anti-tTG), and endomysium (EmA). We compared the performance of assays for anti-nGli, anti-dGli, anti-tTG, and EmA in this age group. METHODS: We investigated retrospectively 184 children (42 with coeliac disease under normal diet and 142 controls) up to 2 years of age. Immunoglobulin (Ig) A- and IgG-anti-dGli, IgA- and IgG-anti-nGli, IgA- and IgG-anti-tTG, and IgA-EmA were measured in serum. Areas under receiver operating characteristics curves, sensitivities, specificities, positive and negative predictive values, positive and negative likelihood ratios, as well as diagnostic odds ratios were calculated. RESULTS: From all of the tests investigated, only assays for IgG-anti-dGli, IgA-anti-tTG, and IgA-EmA had high specificity (≥ 0.96) connected with high sensitivity (≥ 0.86), with high positive predictive values (≥ 0.52 and ≥ 0.69 at pretest probabilities of 0.05 and 0.1, respectively) and negative predictive values (≥ 0.99 and ≥ 0.98 at pretest probabilities of 0.05 and 0.1, respectively). These assays also showed high positive likelihood ratio (≥ 24) at low negative likelihood ratio (≤ 0.15) and high diagnostic odds ratios (≥ 136). CONCLUSIONS: Our results do not support the use of assays of anti-nGli to diagnose coeliac disease in young children. IgA-anti-tTG, IgA-EmA, and IgG-anti-dGli perform better than anti-nGli.