[1] Hokkaido Univ, Sch Med, Cent Res Inst, Dept Internal Med 3,Kita Ku, Sapporo, Hokkaido 0608638, Japan
[2] Hokkaido Univ, Sch Med, Dept Gerontol & Oncol, Kita Ku, Sapporo, Hokkaido 0608638, Japan
[3] Sapporo Immunodiagnost Lab, Sapporo, Hokkaido, Japan
[4] Hokkaido Cent Hosp Social Hlth Insurance, Sapporo, Hokkaido, Japan