After the CD8 cells do their job, they stay in the blood but, all of a sudden, they turn into CD4 cells. And when Penn investigators removed CD4 cells from the blood of Mr. Ludwig and Mr. Olson, they found that those cells could kill B cells in the laboratory. CD4 cells have become killers or, Dr. DiPersio notes, “at least as defenders that can keep tumor cells active and undetectable in patients for years.”
Can CD4 cells remain in the blood and have no cancer cells to destroy? Or are they there because the leukemia hasn’t really gone away but instead they keep trying to come back, only to be attacked by the CD4 cells?
Dr June said: “We couldn’t find any leukemia cells in Doug. Still, he adds, they’re probably still there in very small numbers and emerging, only to be knocked back by the CD4 cells, “like a mole,” he said.
However, he suspects that CD4 cells are more like guardians.
“The leukemia is gone, but they keep working,” he said.
Whatever the mechanism, Dr. Porter said, the results were “beyond the wildest of my imaginations”.
“Oncologists don’t use words like ‘cure’ lightly or easily or to put it bluntly very often,” he said. “I guarantee that it is not used lightly. The patients we treat have had advanced disease,” he notes, adding, “the biggest disappointment is that it doesn’t work all the time. ”
Dr. Hagop M. Kantarjian, chair of the oncology department at the University of Texas MD Anderson Cancer Center, said: “Historically, if these cancers don’t recur within two to five years, the likelihood is recurrence is very low.
For Mr. Olson, now 75 years old and living in Pleasanton, California, life is good. He still shakes his head at the amazing coincidence that his oncologist just happened to be a clinical trial investigator a decade ago.
“I am a lucky man,” he said.
https://www.nytimes.com/2022/02/02/health/leukemia-car-t-immunotherapy.html A cancer treatment makes leukemia go away, but creates more mysteries