1. Division of Rheumatology and Immunology, Brigham and Women's Hospital; Smith 652, One Jimmy Fund Way Boston MA 02115 USA
2. Laboratorium für biochemie, Eidgenossiche Technische Hochschule; CH 8092 Zurich Switzerland
3. Laboratoire de Chimie Biologique, IBMM, Université Libre de Bruxelles; 12 rue des Profs Jeener et Brachet 6041 Gosselies Belgium
4. Department of Cancer Immunology and AIDS, Dana Farber Cancer Institute; 44 Binney Street Boston MA 02115 USA