2 Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, Sapporo, Japan.
3 Department of Surgical Pathology, Hakodate Goryoukaku Hospital, 38-3 Goryoukaku-cho, Hakodate-shi, Hokkaido 040-8611, Japan.
4 Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, South 1, West 17, Chuo-ku, Sapporo, 060-8556, Japan.
5 Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, South 1, West 17, Chuo-ku, Sapporo, 060-8556, Japan. email: tsh715@gmail.com.