Cytokine Panel Blood Test

There are two main causes of chronic inflammation: an inappropriate immune reaction against self (your own cells), or prolonged exposure to an inflammatory stimulus (environmental causes) [3]. In the first group, biology (genetic makeup) is the most important driver that activates chronic inflammation. Let’s call these the “immune-activated” group, which covers a variety of immune system irregularities. Many arthrofibrosis patients were fit and healthy, and their inflammatory status was not apparent until they got arthrofibrosis. Their cytokine panel test results then indicated that they actually were immune-activated.

 

For other people, arthrofibrosis may have been primarily caused by prolonged exposure to an inflammatory stimulus (environmental causes), such as aggressive physiotherapy and high activity levels after surgery, or a misplaced ACL or prosthesis. This group doesn’t have systemic chronic inflammation, so for these people their biology likely plays a less significant role in their arthrofibrosis pathology. We’ll call these people the “immune-regulated” group. With appropriate care these people may recover from injury or surgery to a greater extent (compared to immune-activated people), even without the help of specialised medications.

 

So, it’s important to understand what the main fibrosis drivers are for each individual, as this affects the medications they need. But how do we “sort the sheep from the goats” – they look the same. That is, how do we know who belongs to which group, since on the surface there is often no way to tell.

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Luckily, science is keeping up, and now we have access to more sensitive and specific tests, called cytokine tests. Cytokines are compounds the body makes for protection and healing, but they cause pathology when their production or signalling becomes dysregulated. A blood test to determine the levels of systemic cytokines is very useful for understanding an individual’s inflammatory status. An abnormally elevated level of one or more systemic cytokines suggests that the individual is in the immune-activated group. The classic inflammatory cytokines are TNF-α, IL-1 and IL-6, however there are quite a lot of them. Some cytokines are occasionally referred to as anti-inflammatory, but this label is misleading, because their actions are often context-dependant and in chronic inflammation they can become pro-inflammatory. Some of these, including TGF-β, IL-4 and IL-13 strongly stimulate fibrosis [4], so elevations in these are not a welcome result.

 

In addition to “sorting the sheep from the goats” (understanding if you’re immune-activated), a cytokine panel test can be very useful for indicating which treatments will be the most effective. There are many pathways that can become dysregulated3 and these may arise from innate or adaptive immunity, and be a Th1 or Th2 response. If certain serum cytokines are elevated, they can sometimes be specifically targeted with modern medications that are more effective at reducing inflammation. These medications may also have fewer side-effects that older medications, like corticosteroids, have. A good example of cytokine targeting is the TNF-α antibodies. TNF-α is a key inflammatory cytokine, and a number of IAA members have abnormally elevated TNF-α and would likely benefit from a TNF-α antibody.

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In addition to cytokine tests, blood tests for thyroid function, insulin levels, autoimmune conditions (especially HLA-B27 and rheumatoid factor), general chemistry, infection and complete blood count are recommended for people with arthrofibrosis. A rheumatologist is best placed to order and interpret these tests, but some of them can be ordered by a general practitioner. Cytokine panel testing is relatively new, and some physicians prefer to rely on old methods that are not very useful for people with arthrofibrosis. So, you might have to be proactive and ask your doctor to prescribe a cytokine panel test, and the cost probably won’t be covered by health insurance. You will probably need to call the laboratory that performs the testing to order a kit (see below). Often, the lab will send you forms to complete along with express postage return for the sample, and some companies will also send a sample vial. Blood is then drawn in the usual way by a doctor or nurse into a sample vial. With express courier delivery the sample doesn’t need to be frozen.

 

If you’re given the option, prioritise TNF-α, IL-1, IL-17 and IL-6 as well as TGF-β, CTGF, IL-4, IL-13, IFN- γ and GM-CSF. The more tests you’re able to add, the more complete the picture is. Levels of some cytokine receptors (molecules that cytokines dock with and signal through) are sometimes added in order to understand a person’s biology, e.g. IL-2R, but this varies depending on the test laboratory. In depth genetic testing (other than the standard tests for autoimmune conditions) are interesting but expensive and they’re quite new so the results are less well understood.