[1] Sirindhorn Hosp, Div Hematol, Bangkok, Thailand
[2] Ramathibodi Hosp, Fac Med, Bangkok, Thailand
[3] Mahidol Univ, Louis A Weiss Mem Hosp, Dept Internal Med, Bangkok, Thailand
[4] Texas Tech Univ, Hlth Sci Ctr, Internal Med Dept, Lubbock, TX USA
[5] Texas Tech Univ, Hlth Sci Ctr, Dept Internal Med, 36014th St, Lubbock, TX 79430 USA