Monoclonal Antibodies

For my final blog, I decided to research a monoclonal antibody drug that I have heard of easily three hundred times but really did not have a clue what it did: Humira. If you sit back and close your eyes, I’m sure that you, too, can hear the crystal clear advertisement voice telling you that Humira is the way to go to treat your moderate to severe rheumatoid arthritis. Humira is a monoclonal antibody, which is indicated by its scientific name, adalimumab. But what is a monoclonal antibody? A monoclonal antibody is a huge number of copies of the same specific antibody. This means that each of these antibodies recognizes one particular antigen. These antibodies are produced when an animal is exposed to a particular antigen. The animal’s lymphocytes that make antibodies against that particular antigen will be taken from the blood of the animal and separated from other things that may have been in the blood so all that remains is the pure product of the antibodies specific to the introduced antigen. Once these antibodies are fused with cancerous cells that continue to divide continuously, scientists can make many many copies of the antibodies so they can be used therapeutically in humans. Eventually, enough can be made to be used therapeutically in humans.

As previously mentioned, Humira is a monoclonal antibody. The drug works in the body by blocking tumor necrosis factor, or TNF. When TNF is not functioning properly, it acts in a variety of different ways that wreak havoc on the body. It activates inflammatory responses and specific lymphocytes, and even attacks the body’s own cells by inducing apoptosis. The effects this malfunctioning TNF has on the body can produce the various joint problems associated with rheumatoid arthritis, like swelling, stiffness, and pain. TNF is largely responsible for the condition of rheumatoid arthritis and various other conditions related to inflammation. As such, Humira can be used to treat more than just rheumatoid arthritis. It can also be prescribed for conditions like Crohn’s disease, ulcerative colitis, plaque psoriasis, psoriatic arthritis, and more. However, for the purposes of this blog I’ll be focusing on how it affects rheumatoid arthritis patients. Because Humira blocks the body’s faulty TNF, it reduces the associated pain, swelling, and stiffness in the joints that so many people with rheumatoid arthritis suffer from. Most importantly, it prevents the progression of the permanent joint damage rheumatoid arthritis can result in. Although adalimumab is generally considered a safe medication and will result in no problems for most of those who take it, in some people it can cause unwanted side effects. Such side effects could be mild symptoms to life threatening conditions such as:

• Irritation at the site of injection
• Upper respiratory infections
• Headaches
• Nausea
• Heart failure
• Blood, liver, and nervous system problems
• Serious infections (including Hepatitis B, Tuberculosis, and various others)
• Allergic reactions
• Problems with the immune system including psoriasis and a condition similar to lupus
• Cancer (commonly lymphoma)
• Demyelinating diseases
• Cytopenias
• Malignancies

Like all long lists of side effects, this looks pretty intimidating, especially if you’re already suffering from a condition that is affecting the way your body works. However, some of these conditions can be explained in terms of what Humira does for the body. Of course, when you alter any functional part of the immune system, it will result in the immune response not being as effective in eliminating infections as it was before. This accounts for the increased risk of infections. Because the adaptive immune system’s TNFs cannot activate macrophages and various other lymphocytes, the body is more susceptible to invasion by any form of bacteria, virus, or even fungus. However, it is more than likely that the other mechanisms in your immune response will be able to fight off these infections without the help of TNF, making taking Humira a “necessary evil” since the risk of irreparable joint damage is a greater threat than taking the chance of possibly getting sick more often. However, as previously mentioned, because of these effects on your immune system, taking Humira does increase your risk of getting Tuberculosis and Hepatitis B. You are also advised not to take Humira if you have a current serious infection, as it is likely that the medication’s effects on your immune system would lead to an altered ability to fight it off. Some of the more serious conditions like heart failure can be attributed to the disease itself and not the medication. Patients with rheumatoid arthritis are known to have higher incidence of heart failure. Other conditions can be due to drug interactions and more. Overall, Humira is generally considered a safe way to lessen the symptoms of rheumatoid arthritis.