Cooper started to study the autopsy reports. Again, he found this conundrum: There were plenty of white blood cells—lymphocytes—but very few antibodies. The thymus seemed to be working, but for the most part, the overall immune system was not working. That’s when it hit him. “There were two lineages of lymphocytes,” he said. In other words, the T cell wasn’t the only game in town. The immune system wasn’t connected only to the thymus. There must be more.
