[1] Univ Perugia, Dept Clin & Expt Med, Haematol & Clin Immunol Sect, I-06100 Perugia, Italy
[2] Univ Antwerp, Univ Antwerp Hosp, Div Hematol, B-2650 Edegem, Belgium
[3] Policlin San Matteo, IRCCS, I-27100 Pavia, Italy
[4] Weizmann Inst Sci, Dept Immunol, IL-76100 Rehovot, Israel
[5] Mayo Clin & Mayo Fdn, Mayo Clin Canc Ctr, Stem Cell Lab, Rochester, MN 55905 USA