ABSTRACT Background: Th1 cytokines, IL-2 and IFN-, have critical importance in the CD4 cell driven antimy- cobacterial activity. Th2 type immune response is a characteristic feature of atopic disorders. Th1 and Th2 cells have been reported to negatively cross-reg- ulate each other in vitro and in experimental animals. Our aim in the present study is to determine whether the atopy affects radiological extent of pulmonary tuberculosis (TB) and disease severity. Materials and methods: A total of 82 male patients with pulmonary TB were prospectively enrolled in the study between March 2005 and March 2006. All patients were evaluated for atopic symptoms and TB related systemic symptoms. Radiological dissemina- tion was scored and cavitation was noted. The skin prick test (SPT) was performed and serum total IgE level was measured. Results: The SPTs were positive in 28 of 82 (34.1 %) patients. There was no distinction between SPT-positive and negative patients in terms of pul- monary cavitation and radiological dissemination. The median IgE level of moderate-severe radiologically disseminated TB patients was significantly higher than that of mild radiologically disseminated TB pa- tients (130 IU/ml vs. 58 IU/ml). Cavitary TB patients had also significantly higher median IgE levels (78 IU/ml vs. 46 IU/ml) (p < 0.05) Conclusion: This study suggests that SPT-positivi- ty and atopic respiratory phenotype do not affect the formation of cavitation, radiological dissemination and systemic symptoms of pulmonary TB. The high level of IgE in patients with cavitary and radiologically disseminated TB may be a consequence of a dysreg- ulated immune response to infection or reflect dis- ease activity. Key words: Mycobacterium tuberculosis. Atopy. Skin prick test. Radiological dissemination. INTRODUCTION In antimycobacterial activity, CD4 T cells have dominant protective immune mechanism against Mycobacterium tuberculosis, and Th1 cytokines, IL-2 and IFN-, have critical importance for their func- tion 1 . Infected macrophages and dendritic cells pro- duce IL-12, which is a crucial cytokine in controlling early M. tuberculosis infection. IL-12 regulates the immune system towards to Th1 response with pro- duction of interferon gamma (IFN-) and down regu- lation of IL-10, IL-4 2 . On the other hand, Th2 re- sponse is the main characteristic feature of allergic diseases 3 . When stimulated with allergens or para- Allergol et Immunopathol 2008;36(4):187-90 ORIGINAL ARTICLES Does Atopy Affect the Radiological Extent of Pulmonary Tuberculosis? A. Kutlu a , B. Bozkurt a , F. Ciftci b , E. Bozkanat b , R. Gorur c , G. Sonmez d , S. Ozturk a , O. Taskapan a and Z. Kartaloglu b a Division of Allergy, b Division of Chest Medicine, c Division of Thoracic Surgery, d Division of Radiology. Gulhane Military Medical Academy Haydarpasa Teaching Hospital. Istanbul. Turkey. Correspondence: Dr. Ali Kutlu, MD, Ass. Prof. GATA Haydarpas ¸a Eg ˘itim Hastanesi Allerjik Hastalıklar Servisi 34668, Istanbul, Türkiye Tel: + 90 216 5422020-3410 Mobil: + 90 532 4105582 Fax number: + 90 216 5422765 E-mail: kotiloglu@hotmail.com