Adalimumab Mumbo Jumbo

That is a mouthful.

This week I will be delivering a full helping of information on the monoclonal antibody treatment Adalimumab, a drug that has more information than you can imagine on its FDA page. Adalimumab, under the manufacturer’s name Humira, is a Tumor necrosis factor (TNF) inhibitor used for a variety of different autoimmune disorders where the individual’s TNF naturally has gone a little haywire. As a means of introductions, monoclonal antibody treatments are drugs that consist primarily of an antibody that binds very specifically to a single epitope of an antigen. They are used for blocking and inactivating a variety of different self and non-self things as a means of stopping a certain pathogen or problematic self something-or-another to protect the person.

Humira is one such monoclonal antibody treatment that is used for a small set of different autoimmune disorders where TNF, a cytokine produced by a variety of leukocytes, is implicated as part of the problem. Humira is actually something I am very familiar with as a good friend of mine takes it as treatment for rheumatoid arthritis, a condition where TNF has a problem recognizing tissue in the joints and signals for inflammation and attack of the tissues, causing severe pain and eventual breakdown of the joints if untreated. The antibody in Humira binds to the body’s circulating TNF and inactivates it, preventing it from signaling for inflammation in the joints.

Obviously this is not a perfect solution. If TNF didn’t have any function in the body, it probably would not be produced. TNF functions to induce inflammation, as well as apoptosis in certain situations, such as with cancer cells and infected macrophages. Since it is produced by a variety of leukocytes, macrophages, and T-cells included, this diminishes the capabilities of both the innate and acquired immune systems to respond to infections. The side effects of using Humira are generally things that happen because TNF is not around to prevent them, with a few exceptions. Here is a list so you know what I am talking about:

• Increased risk for systemic infections
• Increased chance for certain malignant cancers
• Increased risk for activation of latent infections such as TB
• Possible Anaphylaxis
• Possible Heart Failure

Now, these are pretty bad, but also very rare, and are monitor-able and treatable for the most part. The individual would be much worse off if they chose not to use this treatment and avoid those risks, as the auto-immune disorders that Humira treats are not self-limiting and are basically guranteed to cause great pain and disability for the individual. Now one thing in particular to keep in mind when starting Humira is that point about activation of latent infections. Humira is contraindicated for individuals with latent TB, as it can cause the infection to become active once TNF is taken out of the picture. The reasoning for this is a bit convoluted, but if you can digest the information in this article, it discusses the fact that TNF helps to induce apoptosis in infected macrophages, which is where TB likes to hide. Without TNF to kill off TB’s breeding grounds, the infection can get out of control. This is why individuals who are about to start taking Humira must get some serious TB testing to make sure they don’t have a latent infection, though it seems to have very little link to arthritis.