T cell immunotherapy is used as a type of cancer treatment that allows the body’s immune system to detect and destroy cancer cells. One of the ways that T cell therapy is used to treat patients is through CD19-targeted chimeric antigen receptor (CAR) modified T cell immunotherapy. According to a journal article from ScienceDirect, a website publishing peer-reviewed science journals, this therapy serves as a treatment that brings promising results in patients with relapsed/refractory lymphoid malignancies. Cluster of differentiation (CD) markers are cell surface molecules that allows scientists to distinguish between subsets of T cells and other white blood cells. Thus, CD19 indicates that it is B cell specific antigen that T cells are modified in the lab to find and destroy.
Before the process of how CAR T cell therapy is further explained, it is important to know the basic understandings of the relationship between antigen and immune receptors. Antigens are proteins that are attached on the surface of foreign substances. The immune system recognizes foreign substances in the body by finding those proteins. When the antigens are detected, T cells, a type of white blood cells, have their own proteins called receptors that attach to the antigens and destroy foreign substances by activating other parts of the immune system. Each foreign antigen has one immune receptor that binds to it. This being said, modifying the T cells is an essential step in the process of CAR modified T cell immunotherapy. As stated in the article on the American Cancer Society website, the white blood cells which includes T cells are removed from the patient’s blood first using the procedure called leukapheresis. After that, the T cells are separated and, in the lab, they are genetically modified by adding man-made chimeric antigen receptor (CAR). Each CAR is made for a specific cancer’s antigen. In the CD19-targeted chimeric antigen receptor modified T cell immunotherapy, CAR is made specifically to target CD19 antigen on the outside of the cancer cells. Therefore, this CAR does not work on cancer cells without CD19 antigens. Before CAR T cells are infused back to the patient, the patient may be given a weak chemotherapy. Chemotherapy helps to reduce the number of other immune cells so that CAR T cells has the chance to be activated. Moreover, it is given not very strong since CAR T cells work the best when there are some cancer cells to attack.
Just like other treatments, there are side effects resulting from CAR T cell therapy. According to the article in the American Cancer Society website, as the CAR T cells multiply rapidly in the body to fight the cancer, it causes chemicals called cytokines to be released in massive amounts into the blood. This release causes the cytokine release syndrome and the patients may experience very high fevers and very low blood pressure. Along with that, CAR T cells can kill good B cells that help fight germs and patients may be at risk for infection. Other serious effect is neurotoxicity and this causes changes in the brain resulting in swelling, confusion, seizures, or severe headaches. The journal article from ScienceDirect includes patient-reported outcomes from receiving CD19-targeted chimeric antigen receptor (CAR) modified T cell immunotherapy. 37.5% of the patients reported cognitive difficulties after the CAR T cell therapy and the article states that there was a trend for a positive association between acute neurotoxicity and self-reported post-CAR T cognitive difficulties. No matter how advanced or minimal treatments may be, side effects and complications still follow as they do with more complicated treatments and they seem unavoidable. Therefore, I believe that taking care of your body and staying healthy are the best preventions and treatments that one can do for him/herself.
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