Evaluation of specific immune response in diagnosis of tuberculosis in children

Tuberculosis (TB) is one of the oldest infectious diseases worldwide. The only method available for TB infection detection has been the tuberculin skin test (TST). Still, this tool has not proved itself as a sensitive method, especially in population previously vaccinated with BCG. The Aim of the Study: to evaluate features of specific immune response in diagnosis of TB in children. The Objectives of the Study: to assess TST in subjects who had contact with TB, and to compare with the results of patients with bacteriologically confirmed TB; to evaluate and to compare T-cell secreting IFN-γ response (T SPOT TB) in subjects with contagious TB and in subjects who had contact with TB; to compare the diagnostic value of in vivo and in vitro tests; to evaluate TST and T SPOT TB results after treatment; to assess the social factors, that may influence children to get TB. 120 subjects had been enrolled in Part I of the Study and 67 in the II. Part I. Evaluation of the immune response - 3 groups of children: “culture-confirmed TB“ group (n=23) – subjects with bacteriologically confirmed TB; “high risk for TB“ group (n=45) - subjects, who had contact with a TB-sick person; “low risk for TB“ group (n=52) – subjects with no identifiable risk for TB. Part II. children were divided into 3 groups, depending on the results of Part I of the study: Children with bacteriologically confirmed-TB (n=23); Children with latent TB infection (n=13); Healthy children (n=31). Conclusions: Positive TST ≥ 10 mm was identified in all children of a bacteriologically confirmed TB group and in more than 50% of the high risk for TB group; the number of persons with positive TST in high risk and low risk for TB groups was similar.Positive T SPOT TB results were identified more frequently in persons having bacteriologically confirmed TB, than in other children. In vitro specimen is more specific in diagnosis of TB infection in children than TST . After treatment, the T SPOT TB resuts reduced considerably, and the reaction of TST did not change. Social factors (close contact with a confirmed case of pulmonary TB, child‘s smoking, lack of ventilation in a living place) might have had the influence on studied children to get TB