TeachableMedicalNews article 06282021

Teachable moment in classrooms:

  1. cellular basis of life chapter – some proteins are located in the plasma membrane
  2. blood chapter – hematopoiesis (blood cell formation) in red bone marrow
  3. immune system chapter – role of T-cells in immune defense

The news item:  Recently an article reported on the struggles of a patient suffering with acute lymphoblastic leukemia:

 

Richmond woman benefits from game-changing cancer treatment now offered at VCU

If you knew what Rachel Elliot has been through you might call it a miracle that she is alive and well today, but hers was a miracle over a decade in the making.

The article described a new treatment called Kymriah, a Car-T type treatment, and stated that it involves genetic engineering T-cells.

So, Why Do I Care??  Some cancers resist traditional chemotherapy treatments. Patients suffering from those cancers have very limited life expectancy.  While the total number of ALL cases, close to 6,000 each year, are relatively few, children under the age of 5 are affected mostly.  New cancer treatment approaches that think outside the box are the treatments that bring hope, and eventually cures to those patients.

Plain English, Please!!!

First, let’s talk about what acute lymphoblastic leukemia (ALL) is. This type of leukemia is the cancer of the red bone marrow, and the uncontrolled division of some cells in the bone marrow leads to a large number of B lymphocytes (a type of white blood cells) released into blood circulation.  Because the cancerous cells divide at a high rate, they take over most of the red bone marrow space, and that leaves little room for making other blood cells, such as red blood cells. As a consequence, anemia develops, and eventually other blood cell-related functions diminish in the body.

Second, let’s talk about how we could fight ALL better. Traditional chemotherapy is marginally effective against ALL. Researchers identified a molecule called CD19 found only on the cancerous bone marrow cells. CD19 represents bullseye target for therapy, so, if we could just find a way to seek out and destroy the CD19 carrier cells, then we could treat ALL better.

Third, let’s talk about how Kymriah treatment targets CD19. In this treatment (the Car-T type treatment) the patients own cytotoxic T cells are trained to find and kill the CD19 carrier cancer cells.  White blood cells are removed from the patient, the cells are genetically modified and cultured to create a large number of activated cytotoxic T-cells, and those cells are infused into the patient.  The genetic modification adds a protein to the cell membrane of the T-cells. That protein (the antigen receptor protein) acts like baseball glove that can grasp the baseball (the CD19 molecule) on the cancer cells. Once the receptor grasps the CD19 molecule, the T-cell release enzymes that destroy the cancer cell.