1. From the Department of Medicine, Pulmonary Section, King Abdulaziz Medical City, Riyadh, Saudi Arabia
2. Correspondence: Dr. Mohammed Al Ghobain · College of Medicine, King Saud bin Abdulaziz University for Health Sciences, PO Box 22490, Riyadh, 11426, Saudi Arabia · alanezi@hotmail.com · Accepted: July 2010
3. From the Department of Pulmonary Medicine, King Saud University, King Khalid University Hospital, Jeddah, Saudi Arabia
4. From the Department of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia