[1] Leiden Univ, Blood Bank, Leiden, Netherlands
[2] Univ Birmingham, CRC, Inst Canc Studies, Birmingham, W Midlands, England
[3] John Radcliffe Hosp, Inst Mol Med, Oxford OX3 9DU, England
[4] CNR, Ctr Immunogenet & Histocompatibil, Turin, Italy
[5] Karolinska Inst, Microbiol & Tumorbiol Ctr, Stockholm, Sweden
[6] CNR, Ctr Cellular & Mol Pharmacol, I-20133 Milan, Italy
[7] Ludwig Inst Canc Res, Brussels, Belgium