Anti-tissue transglutaminase antibodies not related to gluten intake

Introduction: Anti-tissue transglutaminase antibodies (tTG) have high specificity for coeliac disease (CD). However, positive anti-tTG antibodies have been described in non-coeliac patients. Aim: To assess positive anti-tTG antibodies not related to gluten intake. Patients and methods: Retrospective review and follow up conducted on patients with suspected CD (increase anti-tTG levels and gastrointestinal symptoms) but with atypical serology results, positive anti-tTG with gluten free diet and a decrease in anti-tTG levels despite gluten intake. Results: A total of 9 cases were reviewed in which 5 cases had Marsh 3 involvement in the initial biopsy, and were diagnosed with CD (Group A). They began a gluten free diet and also a cow's milk protein (CMP) free diet because of their nutritional status. When CMP was re-introduced, anti-tTG increased, and returned to normal after the CMP was withdrawn again. The other 4 patients had a normal initial biopsy (Group B). Gluten was not removed from their diet, but they started a CMP free diet because a non IgE mediated CMP allergy was suspected. Symptoms disappeared, and anti-tTG was normal after CMP free diet with gluten intake. All the patients had susceptibility haplotype HLA DQ2/DQ8. Conclusions: CMP ingestion after an exclusion diet can induce an increase in anti-tTG in some coeliac subjects. CMP can produce this immune response if there were no gluten transgressions. This response has also been observed in non-IgE mediated CMP allergy patients with the susceptibility haplotype HLA DQ2/DQ8. Resumen: Introducción: Los anticuerpos antitransglutaminasa (ATG) poseen alta especificidad para el diagnóstico de enfermedad celíaca (EC). Sin embargo, se han descrito anticuerpos ATG positivos en pacientes no celíacos. Objetivo: Valorar la presencia de anticuerpos ATG positivos no relacionados con la ingesta de gluten. Pacientes y métodos: Revisión retrospectiva de historias clínicas y seguimiento de pacientes con sospecha de EC y con un comportamiento serológico atípico, es decir, anticuerpos ATG positivos a pesar de una dieta sin gluten y disminución de anticuerpos ATG tomando gluten. Resultados: Se incluyeron 9 casos. De ellos, 5 casos tenían afectación histológica Marsh 3 en la biopsia inicial y diagnóstico de EC (grupo A). Se retiró el gluten de la dieta y se retiraron las proteínas de leche de vaca (PLV) por la afectación nutricional. Al reintroducir las PLV aumentaron los ATG y al retirarlas se volvieron a normalizar