1. From the David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles (J.C.), and Amgen, Thousand Oaks (J.R.P., M.M.) — both in California; MedImmune, Gaithersburg, MD (L.W., S.L.R., J.M.G.); and MedImmune, Cambridge, United Kingdom (R.M.).