[1] Chiba Univ, Grad Sch Med, Dept Orthopaed Surg, Chuo Ku, Chiba 2608670, Japan
[2] Chiba Univ, Grad Sch Med, Dept Med Immunol, Chiba 2608670, Japan
[3] Chiba Univ Hosp, Div Rehabil Med, Chiba, Japan
[4] Kumamoto Univ, AIDS Res Ctr, Div Hemopoiesis, Kumamoto, Japan