1. Chiron srl, Via Fiorentina 1, 53100 Siena, Italy.
2. Institute for Genome Research, 9712 Medical Center Drive, Rockville, MD 20850, USA.
3. Department of Pathology and Experimental Microbiology, University of Messina Medical School, 98125 Messina, Italy.
4. Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02125, USA.