Cytokine Levels in Long Covid






A new study in the Journal of Clinical and Cellular Immunology examines the cytokine levels in long Covid patients. This is a unique study in that it was comprehensive and measured  IL-2, sIL-2r, IL-4, IL-6, IL-8, IL-10, TNFα, IL-13, IL-17, IFNγ, IL-1β, IL-5, and IL-12.

The study included 12 long Covid study participants matched 15 matched, healthy controls.

The results showed that the long Covid patients had lower levels of many of the cytokines tested.

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Notably, interferon-gamma, which responds to viral infection, and IL-8 were decreased 100% compared to healthy controls. IL-8 recruits white blood cells (neutrophils) and natural killer cells to fight off infections.  Additionally, long Covid patients had a 70% reduction in levels of IL-6, and IL-2, IL-17, and IL-13 were reduced by more than 40%. TNF-alpha levels were similar in long Covid and controls.

What does this mean? 

Well, it shows that chronically elevated inflammatory cytokines, seen in chronic diseases like arthritis, diabetes, and heart disease, are likely not the problem in this cohort of long Covid patients.

For people with ME/CFS, TNF-alpha, IL-1B and IL-6 are often elevated.

Some studies on long Covid show persistence of viral infection. If this is the case for these long Covid patients then they aren’t mounting an immune response against the viral infection.

Does this indicate immune system exhaustion? The study authors speculate that immune system exhaustion could be the root cause of long Covid due to the lack of interferon-gamma and IL-8.

One thing not included in the study was whether the long Covid patients were also vaccinated.