1. Department of Microbiology and Immunology and the Cancer Research Institute, University of California–San Francisco, San Francisco, CA;
2. Division of Experimental Medicine, Department of Medicine, University of California–San Francisco, San Francisco, CA;
3. Blood Centers of the Pacific and Blood Systems Research Institute, San Francisco, CA;
4. Institute of Medical Microbiology and Hygiene, Division of Immunology, University of Freiburg, Freiburg, Germany; and
5. Departments of Laboratory Medicine and Medicine, University of California–San Francisco, San Francisco, CA