[1] Kashiwa Tanaka Hosp, Dept Resp Med, 1-3-2 Koaota, Kashiwa, Chiba 2770803, Japan
[2] Kashiwa Tanaka Hosp, Dept Resp Med, Chiba, Japan
[3] Tokyo Med Univ, Ibaraki Med Ctr, Dept Resp Med, Ibaraki, Japan
[4] Japanese Red Cross Med Ctr, Dept Pathol, Tokyo, Japan