Stimulated Cytokine testing: Biomarkers of Immune Status

 

 

 

From: Lingel A, Weiss TM, Niebuhr M, Pan B, Appleton BA, Wiesmann C, Bazan JF, Fairbrother WJ. (2009)Why test immune cytokines?
At NeuroScience, Inc., we always strive to raise awareness about the complex interplay of the neurological, endocrine, and immune subsystems that constitute the NEI SupersystemTM. Because of this interconnectedness,  symptoms such as fatigue, low mood, anxiousness, or insomnia may be due to any number of contributors, not least of which is inflammation. Potential root causes of inflammation include infections, autoimmune disorders, environmental toxins, or disrupted gut microbiota. Even psychosocial stress can result in inflammation!

During inflammation, there is increased production of certain cytokines (small messenger proteins) by white blood cells and other cell types. This can impact neurological and endocrine functions in a number of ways, including the litany of symptoms described above which are sometimes collectively termed “sickness syndrome” or the “sickness response”, an adaptive state that “minimizes risk by limiting normal behavior and social interactions and forcing recuperation” (Chapman et al., 2008).

Not only are these cytokines players in the pathology of a given disorder, they are also reporters of immune imbalance. That’s where Stimulated Cytokine testing comes in.

What is Stimulated Cytokine testing?
Stimulated Cytokine testing is intended to assess whether an individual’s symptoms could be attributable to an imbalanced immune response. Our goal is to understand as best we can where to target therapeutic interventions, minimizing empiricism and guesswork in the therapeutic protocol.

In the test, white blood cells (which include many immune cells) are isolated from a sample of the patient’s blood. These cells are then placed in culture, either without stimulation (defined as baseline), or stimulated with phytohemagglutinin (PHA, a potent stimulator primarily of T cells) or lipopolysaccharide (LPS, principally a powerful stimulator of innate immune cells such as monocytes/macrophages and dendritic cells). After 24 hours, levels of cytokines are measured in the culture medium and compared to the normal range observed in asymptomatic individuals.

Why not just measure serum cytokines?
Many practitioners wonder why they should run a Stimulated Cytokine test; wouldn’t measuring serum cytokines give the same results? The answer is “not necessarily”. That’s because serum cytokine testing can have issues related to reliability and reproducibility, as summarized by de Jager et al. (2009), that are not encountered with stimulated cytokine testing. These issues pertain to sample handling and storage, as well as interference of endogenous plasma proteins.

Another thing to consider is that, unless the patient has a serious case of systemic inflammation, cytokine concentrations in the serum may be too low to detect. In contrast, stimulated cytokine testing first cultures white blood cells over a 24-hour time period, so any cytokines that are secreted in that time frame are concentrated in a small volume of culture medium. Furthermore, being able to stimulate the patient’s white blood cells with PHA and LPS provides a means to expand the dynamic range of the cytokines, while provocation is of course not possible when testing serum cytokines.

What do stimulated cytokine results tell us?
There are a few key proinflammatory cytokines, such as TNF-α and interleukin-1β, for which we know a fair amount about how they may impact the NEI SupersystemTM. For example, IL-1β has been documented to activate the HPA axis, increase norepinephrine release in the hypothalamus, and increase metabolism of 5-hydroxytryptophan toward excitatory quinolinic acid, at the expense of serotonin.

However, at the same time it’s important to recognize that even a test that measures up to 17 cytokines, as NeuroScience, Inc.’s Stimulated Cytokines Comprehensive panel does, is far from actually being “comprehensive”, considering that over 100 cytokines have been described to date! Scientists still do not understand the precise function of many of these cytokines, and partly as a consequence, commercial detection assays do not include them (though this will certainly evolve over the coming years).

Therefore, we need to stay humble and realize that the cytokines we can test for today are unlikely to give us the whole story about what is going on in an individual. Imagine you were trying to understand someone who was speaking in a language for which you only knew 17 words! Nonetheless, if you heard the words “danger”, “help”, and “fire”, you would have a decent idea as to the meaning of the message. Similarly, perturbations in the cytokines that we are able to commercially assess are extremely useful as indicators of the patient’s immune status, or to use the more formal lingo, they are biomarkers of the immune system.

Thus ends Part 1 of my commentary on cytokine testing – In an upcoming entry, I’ll walk through a couple of Stimulated Cytokine test cases and provide some interpretative guidelines to apply in practice! Remember, in order to appropriately target interventions, we need to understand whether immune imbalances are an underlying issue.

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7 Responses to Stimulated Cytokine testing: Biomarkers of Immune Status

  1. Sirid –
    For those just breaking into the usefulness of biomarker testing for the NEI SuperSystem this post is a good first step on the immune side of the equation. Just thinking about immunity can significantly change the lives of the people we treat. If we do consider immunity, proper testing will follow. Evidence matters.

    From my psychiatric-practice-perspective, dealing with the significant challenges of so many patients dubbed “psychiatric” with associated chronic disease states, it’s just amazing how many suffer from significant, never measured, immune dysfunction. It’s at once sad and interesting that so many don’t understand even the basics of IgG testing and the value of looking at how commonplace these immunity issues are in everyday practice.

    Consider these two boys evaluated for treatment-resistant ADHD:
    1. Many years ago I saw the young son of an MD, GI specialist, who at first dismissed the SPECT brain findings when I reported not only ADHD findings, but that the SPECT brain findings appeared also likely associated with metabolic challenges, likely gluten sensitivity, possibly even celiac. At first he discounted my suggesting replying that the celiac blood tests were negative. Ultimately IgG testing revealed casein as seriously contributory, and the boy significantly improved. For a brief review of SPECT and gluten see this post:
    http://www.corepsychblog.com/2008/01/spect-imaging-notes-more-on-celiac-brain-hypofunction/

    2. Just last week another 5 yo boy, son of a prominent internist in Norfolk and another overt skeptic who straightforwardly put off my recommended testing for months, showed dramatically negative results with simple IgG testing alone. The choice I repeatedly put to him: Stay on the emergency Abilify through grade school and adolescence, or find out the underlying problem. Wheat, milk, and eggs were all markedly elevated and matched the clinical symptom picture of contributory GI impairment with refractory response to psych meds. Quite typically his son markedly deteriorated on any stimulants [already significantly elevated on dopamine], Intuniv helped just a bit [already over the top on glutamate], and Abilify was the only med that could keep the boy from being kicked out of his third pre-school for hitting and outrageous behaviors.

    These two boys are very typical samples that encourage every practitioner to start somewhere with these next testing steps, even with basic IgG testing, as we all move down the path to understanding and applying these more difficult cytokine elements.

    Thanks for helping clarify these useful concepts for determined practitioners seeking new tools for the many complex psychiatric presentations.

    cp
    Author: ADHD Medication Rules – Paying Attention To The Meds For Paying Attention

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  6. Del says:

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  7. I’m so glad I stumbled across this website, these blogs are magnificent, even for someone to read who is not in the medical profession. I have been poorly for a long time and tests are becoming more complex where I have no resulted at Encrinology. With our healthcare system in the UK , its very hard to get the medical professions to look deeper and deeper into things. Trying to understand what I can with parts of my body and how its acting is key to make sure I am getting all the help that’s needed. This is certainly a starting platform to work off in my research that I can do when I am not feeling as poorly on certain days. This blog is so informative and simple in its explanations, so thank you.

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