Monoclonal Antibodies

Rituximab (RITUXAN) is an example of a monoclonal antibody drug that has been used to help fight rheumatoid arthritis and other types of cancer like Non-Hodgkin’s Lymphoma. From our latest discussion’s in class we know that antibodies are proteins that can bind to specific antigens and are essential in our immune responses. However, I had never heard of monoclonal antibodies and according to the book they are identical antibodies, with the same constant and variable regions. Having consistency between a large number of antibodies makes reliable and precise tests available. According to the Mayo clinic, monoclonal antibodies can be used to help target numerous types of cancer, Rituximab being a perfect example.

When specifically looking at how rituximab works against Non-Hodgkins lymphoma, I discovered that it targets a molecule on the surface of B cells called CD20. CD20 can effect the growth and differentiate of a B cell. The monoclonal antibodies associated with this drug were designed to bind to the receptor and cause the tumorous B cells to lyse. With lysing these cells, rituximab can help slow the growth of tumors, or even stop them from reoccurring. It is administered to patients through infusion therapy which can lead to serious side effects. These side effects include:

• Hives or rash
• itching
• swelling of your lips, tongue, throat or face
• sudden cough
• shortness of breath or wheezing
• weakness
• dizziness of fainting
• palpitations
• chest pain
• painful sores or ulcers on your skin, lips or in your mouth
• confusion
• vision problems
• difficulty walking or talking
• nausea
• diarrhea
• muscle spasms
• more frequent upper respiratory tract infections

Some of the more serious side effects include things like severe skin and mouth reactions, Hepatitis B virus reactivation, kidney problems, and tumor lysis syndrome. Tumor lysis syndrome (TLS) is probably the most prominent and patients who are receiving Rituxan for Non-Hodgkin’s Lymphoma need to be most careful about. TLS happens when there are a lot of lysis of tumor cells ( which is the main function of Rituxan), which makes you susceptible to kidney failure and could end up having to go on dialysis. You will not be treated with Rituxan if you are pregnant of breastfeeding, and it will depend on a person to person bases if you have had hepatitis B or tuberculosis before if your doctor administers rituxan. This is due to the fact that it can cause a reactivation of the Hepatitis B and it also is a severe immunosuppressant drug so it can leaves your body open to various other infections. I couldn’t find a source that exactly laid out which part of the immune system is being affected here but from what I can guess it is mainly the adaptive immunity that is being suppressed. Whenever we have a large amount of cell lysing going on there is normally an adaptive immune response and with cell lysing being rituxan’s main function, i can imagine that it also suppresses some of the adaptive immune responses in order to fully do its job against cancerous cells.