Inverse relation between atopic status and tuberculin response in adult asthmatics

INTRODUCTION: We aimed to examine the relation between tuberculosis infection and both atopic and nonatopic asthma. MATERIALS AND METHODS: Eighty six patients with asthma were included. These patients were divided into two groups according to atopic status. Seventy one patients with positive prick tests to at least one aeroallergen together with history of allergy were named as atopic asthma group, and the other 15 patients with negative prick tests, who do not have any history of allergy were named as nonatopic asthma group. Two different control groups similar in terms of age and gender were taken for each group. Tuberculin skin test was done. RESULTS: As a different from most of the previous studies, we included nonatopic asthmatics besides atopic asthma group. PPD value in atopic asthma group was significantly lower (p< 0.001) than the control group. In nonatopic asthmatics, PPD value was also lower than the control group, but it wasn't statistically significant. When we take all patients and controls, negative correlation was seen between mean PPD value and total IgE levels. CONCLUSION: PPD reactivity has been detected as remarkably suppressed in atopic asthma group while mildly suppressed in nonatopic asthmatics. The results may be affected by the fact that mycobacterium infection or BCG vaccination may have suppressive effect on atopic asthma development which comes out in early ages, but they don't have the same effect on nonatopic asthma development which comes out in elder ages.