At NeuroScience, our appreciation of the Neuro-Endo-Immune Supersystem makes it a priority for us to help healthcare practitioners understand the contribution of chronic immune activation (inflammation) to overall health. That’s why we offer an extensive suite of immune testing, including cytokine testing, Lyme testing (iSpot Lyme), and food allergy testing . Here’s another important component of NeuroScience’s testing portfolio – the MELISA®. I’m just going to cover some high points here; you can learn more at www.neuroscienceinc.com/melisa.
MELISA (pronounced me-LYE-za) stands for Memory Lymphocyte Immunostimulation Assay. As you can learn at the MELISA Medica Foundation’s website, the test was originally developed for the diagnosis of occupational allergies at Astra Pharmaceuticals (now AstraZeneca). Since that time, it has proved clinically useful in identifying metal hypersensitivities that can affect our overall health in many ways.
Let’s start by discussing what it means to have a metal hypersensitivity. All of us are exposed to metals in our daily lives, in sometimes unexpected ways. Metals can be found in the foods we eat (and not just contaminated fish!), dental amalgams, jewelry, medications, cigarette smoke, surgical implants, occupational exposure…the list goes on and on. In some exposed individuals, certain metals that enter our bodies modify our own proteins in such a way that we develop an immune response, or hypersensitivity, to these metal-modified proteins.
Patients with documented metal hypersensitivities have a wide array of symptoms, as you would expect from someone having an chronically activated immune system along with all the potential downstream effects on neurological and cognitive health. These include:
- Persistent fever
- Chronic headaches or migraines
- Unexplained rashes
- Thyroid disorders
- Impaired cognitive function
- Chronic fatigue
- Musculoskeletal pain
The MELISA is a way of testing whether a person has such hypersensitivity, and to which metal(s). Here’s how the test works.
- A patient sends a blood sample into the lab.
- Their white blood cells (immune cells) are incubated for several days with individual metals.
- If the patient has a hypersensitivity to a particular metal, their white blood cells contain T cells that react to that metal. When these T cells re-encounter that metal in the culture, they divide (proliferate), and so there are more cells at the end of the culture period compared to a control culture with no metal added. Conversely, if there has not been a past immune response to a given metal, there will be little or no proliferation.
- Therefore, we can assess metal hypersensitivity by measuring how much T cell proliferation has occurred in response to that metal.
The MELISA test is distinctive from other metal tests. For one thing, metal hypersensitivity is not the same as metal toxicity. Hypersensitivity can be caused by very low amounts of metal, well below the levels considered to be toxic as detected in tests that assess metal levels in hair, nails, and bodily fluids. In addition, some metals may not be excreted in hair or nails, leading to false negative results for these types of tests.
In addition, MELISA is less likely to generate false negative results compared to other methods that aim to detect a past immune response to foreign substances, such as Clifford Materials Reactivity Testing (CMRT) that looks for antibodies to such substances. There are two reasons for this:
- While the immune system retains a “memory” of a past exposure to a metal in the form of both memory T cells and antibodies, with time this memory “dims”, to the point where antibodies may become undetectable in a serological assay. In contrast, in the MELISA assay there’s a 5-day culture that gives any residual metal-reactive memory T cells time to proliferate and expand their numbers, making them more likely to become detectable.
- In some individuals, metal hypersensitivity may only involve the cellular component of our immune system and never stimulate antibody production.
Deciding whether someone with symptoms should receive a MELISA test may sometimes be a bit of a no-brainer if there are obvious clues, like recent dental work (amalgam removal, for instance), diets high in fish, or occupations with obvious metal exposure such as plumber, electrician, hairdresser, or dentist. But as I mentioned earlier, metal exposure can come from a wide variety of sources and isn’t always obvious. If you feel like you’ve ruled out other possible root causes for patient symptoms, don’t forget that a little metal can do a whole lot of harm.