[Feature] The Avenger

David Fajgenbaum was in his third year of medical school at the University of Pennsylvania (UPenn) 6 years ago, on an obstetrics-gynecology rotation, when he was first hit by night sweats, fatigue, and weight loss. His eventual diagnosis: a deadly form of Castleman disease, a rare immune disorder for which knowledge was in depressingly short supply. So Fajgenbaum decided to dedicate himself to taking down this disease. He abandoned plans to become an oncologist, skipped medical residency, and