CAR T Cell Therapy

What is it?

While there are myriad new therapies that have emerged since the dawn of genetic engineering, one of the most promising and exciting is the one known as chimeric antigen receptor T cell therapy or CAR T cell therapy. Our immune system is very good at its job. On a weekly basis, we encounter many bacteria and viral particles. In addition, every day, many cells in our body mutate to become cancerous. However, most of us do not get deathly sick or develop cancer on any given week. This is thanks to our immune system, which is able to specifically target these pathogens or cancer cells and eliminate them from our body. CAR T cell therapy utilizes the human immune system to target a number of diseases, especially cancers. A sample of blood is taken from the patient and T cells are isolated. Then, these T cells are genetically modified to create a surface receptor that targets a given disease. The cells are cloned and then injected back into the patient. These cells will now target and kill whatever cells display the antigen the genetically modified T cells now recognize. According to an article released by the American Cancer Society, “the relationship between antigens and immune receptors is like a lock and key. Just as every lock can only be opened with the right key, each foreign antigen has a unique immune receptor that is able to bind to it”. CAR T cell therapy essentially gives our immune system the proper “key”.

CAR T Cell Therapy in Treating B Cell Lymphoma

A great example of CAR T cell therapy in action is its employment against a number of lymphomas and leukemia. I will specifically discuss its use against B cell lymphoma. According to a release from Eurekalert!, the CD19 antigen is expressed in B cell lymphoma and and other lymphatic cancers. This provides a target that is specific to the cancer cells, which should not target healthy cells. Thus, T cells are extracted from the patient and genetically modified to produce an anti-CD19 receptor. They are then grown up and reintroduced into the patient’s system where they find and kill cancerous B cells.

Side Effects

When I was initially researching CAR T cell therapy, I thought that there would be little to no side effects since the modified T cells are were part of the patient’s own body. However, I soon realized this was a silly assumption. According to the previously mentioned American Cancer Society article, there are several side effects of CAR T cell therapy. These can include flu-like symptoms and cytokine release syndrome or CRS. T cytotoxic cells, the cells used in CAR T cell therapy, kill targeted cells with toxic cytokines. Unfortunately, these can accumulate in the blood of the patient and cause these flu-like symptoms. Less often, the T cells can target healthy B cells, which can leave the patient more prone to infection of pathogens.