[1] Massachusetts Gen Hosp, Partner AIDS Res Ctr, Boston, MA 02114 USA
[2] Massachusetts Gen Hosp, Div Infect Dis, Boston, MA 02114 USA
[3] Harvard Univ, Sch Med, Boston, MA USA
[4] First Affiliated Hosp China Med Univ, AIDS Res Ctr, Shenyang, Peoples R China
[5] John Radcliffe Hosp, Nuffield Dept Med, Oxford OX3 9DU, England