1. Global Translational Medicine, Pfizer Global Research and Development, Pfizer Inc, New London, CT 23240, U.S.A.
2. Clinical Strategies, BioAdvance, Philadelphia, PA 19104, U.S.A.
3. Laboratory Medicine Department, University Hospital of Padova, Padova, Italy
4. Immunogenetics Section, Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892, U.S.A.