321 Received April 6, 2012; revision accepted for publication July 4, 2012. doi: 10.1620/tjem.227.321 *E.K. Kim and J.H. Lee contributed equally to this work. Correspondence: Sang-Do Lee, M.D., Ph.D., Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Asan Medical Center, College of Medicine, University of Ulsan, 388-1 Poongnab-dong, Songpa-gu, Seoul 138-736, Kor...