ABSTRACT Background: Hypothyroidism due to Hashimoto's thyroiditis (HT) is the commonest autoimmune endocrine illness in which antibodies against thyroid organ result in inflammation. The disease has a complex etiology that involves genetic and environmental influences. Viral infections may be involved in triggering of the disease as their molecular mimicry enhance autoimmune responses. Human herpesvirus-6 (HHV-6) is recognized for its contribution to some autoimmune diseases. Objective: In the current study, the prevalence of HHV-6 active infection in patients with HT and with non-autoimmune thyroid disorders were compared with patients with euthyroidism. In addition, a correlation between presence of HHV-6 infections and HT was investigated. Methods: A total of 151 patients with clinically and laboratory confirmed HT, 59 patients with non-autoimmune thyroid disorders, and 32 patients with normal thyroid function were included in the study. For further confirmation of HT disease, all the precipitants were tested for anti-thyroid peroxidase (TPO), and anti-thyroglobulin (TG) antibodies. For detection of both HHV-6 types A and B, nested PCR and restriction enzyme digestion were used. HHV-6 DNA positive samples were further investigated by DNA sequencing analysis. Results: HHV-6A DNA was found in serum sample of 57 out of 151 patients (38%) with HT, which was significantly more often than in patients with non-autoimmune thyroid disorders (p = 0.001). However, HHV-6 DNA was not detected in serum samples of euthyroid subjects. Conclusions: The results support a possible role for active HHV-6A infection, demonstrated by the presence of HHV-6 DNA in sera, in the development of HT.

RESUMO Contexto - A infecção por Helicobacter pylori, bacilo gram negativo, tem estreita associação com gastrite antral crônica. Objetivo - Neste estudo, avaliou-se a precisão do teste respiratório da urease (UBT) com isótopos de carbono 13 em comparação com a histopatologia do antro gástrico para detecção da infecção por H. pylori em crianças com dispepsia. Métodos - Estudo transversal realizado no laboratório especializado no Centro de Pesquisa Gastroenterológica de Shiraz e do Hospital de Nemazee, Iran, durante um período de 12 meses. Este estudo investigou a sensibilidade, a especificidade e valores preditivos positivos e negativos da UBT em comparação com testes baseados em biópsia. Incluímos uma seleção consecutiva de 60 crianças que preencheram os critérios de Roma III para dispepsia. Todas as crianças foram encaminhadas para a realização de UBT com isótopos de carbono 13 (C13) assim como endoscopia. Biópsias foram tiradas do antro do estômago e duodeno. O diagnóstico patológico era considerado o teste padrão. Resultados - A idade média dos participantes foi 10.1±2.6 (intervalo de 7 a 17 anos). Do nosso total de 60 pacientes, 28 (46,7%) tiveram resultados positivos UBT e 32 (53,3%) tiveram resultados negativos de UBT. Dezesseis (57,1%) de 28 pacientes que tiveram UBT positiva foram H. pylori positivo e 12 (42,9%) foram negativos. A sensibilidade e especificidade do C13-UBT para detecção da infecção por H. pylori foi de 76,2% e 69,2%, respectivamente. Conclusão - A sensibilidade e especificidade do C13-UBT para detecção da infecção por H. pylori foi de 76,2% e 69,2%, respectivamente. Recomenda-se outro estudo multicêntrico de nosso país.

ABSTRACT Background - Helicobacter pylori infection is the gram negative bacillus with the close association with chronic antral gastritis. Objective - In this study, we evaluate the accuracy of urea breath test (UBT) with carbon isotope 13 in comparison with histopathology of gastric antrum for detection of H. pylori infection in children with dyspepsia. Methods - This cross-sectional study was performed at specialized laboratory of Shiraz Gastroenterohepatology Research Center and Nemazee Hospital, Iran, during a 12-months period. This study investigated the sensitivity, specificity, and positive and negative predictive values of UBT in comparison with biopsy-based tests. We included a consecutive selection of 60 children who fulfilled Rome III criteria for dyspepsia. All children were referred for performing UBT with carbon isotope 13 (C13) as well as endoscopy. Biopsies were taken from antrum of stomach and duodenum. The pathologic diagnosis was considered as the standard test. Results - The mean age of the participants was 10.1±2.6 (range 7-17 years). From our total 60 patients, 28 (46.7%) had positive UBT results and 32 (53.3%) had negative UBT results. Pathologic report of 16 (57.1%) out of 28 patients who had positive UBT were positive for H. pylori and 12 (42.9%) ones were negative. Sensitivity and specificity of C13-UBT for detection of H. pylori infection were 76.2% and 69.2% respectively. Conclusion - Sensitivity and specificity of C13-UBT for detection of H. pylori infection were 76.2% and 69.2% respectively. Another multicenter study from our country is recommended.