1. The Center for Blood Research, Harvard Medical School, Boston, Massachusetts 02115
2. Novartis Forschungsinstitut, A-1235 Vienna, Austria
3. Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115
4. Department of Immunology, Toho University School of Medicine, Tokyo 143-8540, Japan
5. Division of Cardiology, Duke University Medical Center, Durham, North Carolina 27710
6. Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
7. Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115