Research Papers

Mast Cell Activation Syndrome Present in Long-COVID Patients


The purpose of this paper was to determine the prevalence and severity of mast cell activation in long-COVID, which has been hypothesised as a contributing factor to the persistent symptoms that exist after an initial COVID-19 infection. Adults with long-COVID were given online assessments of their symptoms before and after their initial COVID-19 infection. The questions pertained to common allergic symptoms of mast cell activation, as well as common COVID-19 symptoms such as fatigue. The long-COVID group was then compared to individuals from the general population with mast cell activation syndrome, without an initial COVID-19 infection. The results showed that mast cell activation symptoms were increased in the long-COVID cohort, which the researchers believe are due to increased activation of mast cells induced by a COVID-19 infection.

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Objectives: Hyper-inflammation caused by COVID-19 may be mediated by mast cell activation (MCA) which has also been hypothesized to cause Long-COVID (LC) symptoms. We determined prevalence/severity of MCA symptoms in LC. Methods: Adults in LC-focused Facebook support groups were recruited for online assessment of symptoms before and after COVID-19. Questions included presence and severity of known MCA and LC symptoms and validated assessments of fatigue and quality of life. General population controls and mast cell activation syndrome (MCAS) patients were recruited for comparison if they were ≥18 years of age and never had overt COVID-19 symptoms. Results: There were 136 LC subjects (89.7% females, age 46.9 ±12.9 years), 136 controls (65.4% females, age 49.2 ±15.5), and 80 MCAS patients (85.0% females, age 47.7 ±16.4). Pre-COVID-19 LC subjects and controls had virtually identical MCA symptom and severity analysis. Post-COVID-19 LC subjects and MCAS patients prior to treatment had virtually identical MCA symptom and severity analysis. Conclusions: MCA symptoms were increased in LC and mimicked the symptoms and severity reported by patients who have MCAS. Increased activation of aberrant mast cells induced by SARS-CoV-2 infection by various mechanisms may underlie part of the pathophysiology of LC, possibly suggesting routes to effective therapy.


Article Publication Date: 23/09/2022
DOI: 10.1016/j.ijid.2021.09.043

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