By Veronica Villanueva, C2ST Intern, Rush University
Systemic lupus erythematosus (commonly referred to as lupus) is an autoimmune disease that causes a person’s own immune system to attack their body. Like many autoimmune diseases, there is no cure. Consequently, most lupus treatments focus on reducing symptoms and improving patients’ quality of life. The quest for a cure is ongoing. However scientists recently found promising results in an unexpected place: cancer treatments.
To understand why these results are unexpected, we must first understand a major difference between lupus and cancer: inflammation.
Cancer is a disease caused by uncontrolled cellular growth which may localize to a specific organ or metastasize (spread) throughout the body. Cancer cells are treated as foreign by the body. When something exists in our bodies that shouldn’t be there, the body responds with inflammation. Inflammation is caused by an influx of immune cells to areas with injury or foreign bodies so that these immune cells can identify (tag) and resolve the problems. In a perfect world, the inflammation would tag all the cancer cells so the immune system destroys them and the cancer would disappear, but cancer is sneaky and it fights back. Different cancers have mechanisms to reduce the body’s inflammatory response, thus impeding the body’s fight against the disease. Due to this fact, many scientists call cancer an anti-inflammatory disease.
Lupus, on the other hand, is distinctly inflammatory. One way the immune system tags cells for destruction is through antibodies. Antibodies are essentially red flags that attach to foreign bodies, damaged cells, and other invaders, calling other immune cells to destroy them. These antibodies are produced by immune cells called B cells. In lupus, B cells produce antibodies that attach to healthy cells and tissue, damaging important parts of the body.
With this basic understanding that cancer is anti-inflammatory and lupus is inflammatory, it seems logical that medicine for each disease would have opposite goals. But a recent study published in the New England Journal of Medicine showed that two well-known cancer therapeutics, chemotherapy and CAR-T therapy, may be an amazing option for lupus treatment.
Chimeric antigen receptor (CAR) T cells (called CAR-T cells) are genetically modified immune cells which are engineered to seek out specific cells. Often called a “living therapeutic,” CAR-T cells start out as regular T cells taken from the patient awaiting treatment. These T cells are modified to produce CARs on their surface which are designed to target specific proteins. In the case of lupus, CAR-T cells were made to target B cells. This treatment reduced B cell levels in patients thus reducing the antibodies causing inflammation and damage.
To further reduce B cells, patients were also treated with chemotherapy before being given CAR-T cells. Chemotherapy drugs are medicines which kill fast growing cells, it is often used in cancer treatment but can be used to reduce immune cell growth in patients with overactive immune systems (like lupus or rheumatoid arthritis). CAR-T and chemotherapy combined led to reduction in B cells, antibody production, and kidney damage over 40 days post treatment.
If this treatment has resulted in positive outcomes, then why is it not in wider use? Cancer therapeutics for autoimmune disease treatment are still in the earliest stages of research. More studies are required to assess the long term benefits (or problems) with the treatment. There are some known issues with CAR-T therapy including inconsistent results and large costs, additionally, chemotherapy causes several side effects. Overall, cancer therapeutics are a promising solution to autoimmune diseases but more evidence is needed before widespread use.