Does the atopic phenotype prevent development of active tuberculosis infection?

This study investigated the relationship between the atopic phenotype and the development of active tuberculosis. A total of 82 human immunodeficiency virus negative males with active pulmonary tuberculosis and 88 healthy controls were enrolled into this prospective study. Serum immunoglobulin E (IgE) levels were measured and skin prick tests performed before initiation of treatment. Skin prick tests were positive in 34.1% of the tuberculosis patients and 39.8% of the controls. Allergic respiratory symptoms were significantly less frequent in skin prick test positive tuberculosis patients (21.4%) compared with skin prick test positive controls (62.9%). Median IgE levels in atopic tuberculosis patients were significantly higher than in atopic controls. The low rate of atopic respiratory complaints seen in the tuberculosis patients, despite having similar allergic skin prick test sensitivities to the controls, could be attributed to a weak T-helper (Th) 2 immune reaction and its effects on Th1-Th2 interaction.