Y Izumiya1, Y Okuda1, S Ueki2, M Takeda1, K Sato1, K Nakayama1. 1. Department of Respiratory Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan. 2. Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.