This is a very interesting article. A piece I did not understand until I did some additional research was this part:
"Oncologists in the southeastern United States noticed something strange. In Tennessee and North Carolina, 22% of cetuximab patients suffered immediate hypersensitivity reactions on their first infusion. In the northeastern US, the figure was under 1%.⁷ The regional pattern was striking. Patients were reacting violently to a drug they had never been exposed to before, which meant something had sensitized them in advance."