[1] Pisa Univ Hosp, North Western Tuscany Blood Bank, Pisa, Italy
[2] Carlo Poma Hosp, Div Hematol & Transfus Med, Mantua, Italy
[3] Natl Inst Infect Dis Lazzaro Spallanzani IRCCS, Rome, Italy
[4] Johns Hopkins Univ, Sch Med, Dept Med, Baltimore, MD 21205 USA