Dr. Dinarello called it a leukocytic pyrogen—a fire starter born of the white blood cells, the leukocytes. “He realized, ‘Oh my god, it’s not coming from the neutrophil. It’s coming from the monocyte,’” recalled Dr. Fauci, who worked with Dr. Dinarello on the eleventh floor. When Dr. Fauci related the story to me, his own voice rose with elation. His excitement took a moment for me, an outsider, to appreciate, given how thick these conversations are with immunology speak. But
