T-Cell Testing vs. Antibody Testing for Lyme disease - What’s the difference?
Contrary to popular belief, there is no “best test” for Lyme disease. Because it can be difficult to detect the bacteria (Borrelia burgdorferi) directly, most initial tests rely on measuring the immune response as an indirect indicator of exposure to the bug and consequently infection.
But there are different ways that the immune system can respond to infectious organisms and different ways to measure immune activity against a specific infection.
The conventionally accepted method for measuring immune activity against Borrelia burgdorferi is based on specific antibody levels. Antibodies are produced by B-cells, which are a type of white blood cell or immune cell that are present in the body. Antibodies come in different forms but the predominant forms are IgM and IgG type antibodies. Generally speaking, IgM antibodies are elevated early in infection and IgG type antibodies are present in later infection or may be indicative of past exposure. Both are usually measured to assess likelihood of Lyme disease and co-infections.
The Benefit of T-Cell Testing
Sometimes it can take a while after you are exposed to an infectious organism before you make high enough levels of antibodies to be detected on the test. This is referred to as seroconversion. In the context of Lyme disease, seroconversion is highly variable and can take anywhere from 4-6 weeks or longer. There is also some evidence that some people with a true Borrelia burgdorferi infection never seroconvert or make the IgG type antibodies which are required for conventional lab diagnosis. Since antibodies may also be suggestive of past exposure, it may be harder to distinguish current infection from past exposure using antibody based testing.
Another group of white blood cells called T-cells may show measurable Borrelia and co-infection specific responses following exposure and can be utilized as an indirect measurement for infection. An advantage of measuring T-cell response versus antibodies (from B-cells) is that it may be more indicative of current infection since theoretically T-cells that are activated for specific infections should not remain reactive after an infection has cleared. This type of testing is not used conventionally for diagnosis of Lyme disease and co-infections like antibody based testing but may give us useful information for current vs. active infection when you consider the results in the context of your clinical history, signs and symptoms.
Our Approach to Testing
At Tandem Clinic we often use a combination of different types of testing so that we have more information to help inform our clinical diagnosis for Lyme and tick borne illness. We also choose tests that represent more of the known strains of Borrelia and other tick borne bugs so that we can be more confident that we aren’t missing infections that could change the course of treatment.
The moral of the story is this - there is no one size fits all test in the setting of Lyme disease and tick borne illness more broadly. However when these tests are used appropriately and in the context of a person’s symptoms and health history, they can be extremely valuable in guiding the assessment and treatment of patients with complex unexplained illnesses like Lyme and tick borne illness.
Our team at Tandem Clinic is here to work with you to guide you through the sometimes complex process of testing and treatment of complex illnesses.
In health,
Dr. Carolyn Mukai, ND
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