Many people are asking New Orleans Coroner, Dr. Dwight McKenna, what is immunotherapy?

Dr. McKenna says immunotherapy is different from other cancer therapies that work in the bloodstream. Instead of destroying both cancer cells and healthy cells, as chemotherapy does, immunotherapy drugs help the immune system recognize cancer cells as invaders and work to get rid of them.

Immunotherapy drugs help immune cells in the body – white blood cells known as T lymphocytes or T cells – recognize that cancer cells don’t belong there. Dr. McKenna says the second function of immune therapy is to help boost the strength of the T cells to actually kill the cancer.

The immune system uses immune checkpoints to make sure healthy cells aren’t destroyed during an immune response. The T cells recognize and bind to certain proteins. This creates a stop sign that tells the T cells to stop their disease fighting work and protects healthy cells. These checkpoints keep the immune system from recognizing cancer cells, allowing tumors to grow.

Dr. McKenna says immunotherapy drugs called immune checkpoint inhibitors keep these proteins from binding and prevent the body from sending a stop signal to T cells. When they don’t receive this stop signal, T cells attack cancer cells, shrinking tumors or preventing them from growing. Immunotherapy basically retrains the immune system and turns it back on so that it then recognizes cancer as something that shouldn’t be there, experts say.