Tag: mast cell activation syndrome

A Continuous Oral Regimen of High-Dose Cromolyn Sodium Is Effective for Some Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Patients With Mast Cell Activation Syndrome

Abstract:

Our clinical experience in the last four years using oral cromolyn in patients with mast cell activation syndrome (MCAS) suggests that a continuous oral regimen of high-dose cromolyn may enhance compliance with the medication. The five patients described in this retrospective case series were given instructions to take oral cromolyn using a continuous dosing regimen, placing the entire day’s dose in an opaque bottle that is then filled with water, and sipping the solution throughout the day. If a conventional maximum dose of eight vials daily (800 mg) was tolerated but ineffective after a week, the patients were instructed to increase to 1600-2400 mg daily until reaching an optimal effect.

We report that a cromolyn dose of 1600-2400 mg daily, administered using the continuous oral dosing regimen during the day, was effective in controlling signs and symptoms of mast cell activation. All five patients benefitted from a dose of cromolyn that is higher than usual and customary recommendations, but within the safety guidelines of the original Food and Drug Administration (FDA) application. The continuous oral regimen has some theoretical advantages over four discrete doses per day, though further study is needed.

Source: Christoforou ME, van Campen LC, Visser FC, Lee CK, Lemmon SL, Rowe PC, Azola AM. A Continuous Oral Regimen of High-Dose Cromolyn Sodium Is Effective for Some Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Patients With Mast Cell Activation Syndrome. Cureus. 2026 Jan 22;18(1):e102064. doi: 10.7759/cureus.102064. PMID: 41728426; PMCID: PMC12924640. https://pmc.ncbi.nlm.nih.gov/articles/PMC12924640/ (Full text)

The Clinical Relevance of Mast Cell Activation in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Background/Objectives: Growing evidence suggests that mast cell activation (MCA) may contribute to Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), a debilitating disorder characterized by persistent fatigue and post-exertional malaise (PEM). Particularly in relation to orthostatic intolerance (OI), including postural orthostatic tachycardia syndrome (POTS), this study aimed to investigate the prevalence and clinical relevance of MCA in an Austrian ME/CFS patient cohort.

Methods: Two data sets were analyzed. The CCCFS data set, a comprehensive, patient-centered online questionnaire consisting of 687 filled surveys, focuses on patient stratification. Self-reported clinical features, disease progression, and treatment responses were analyzed. Preliminary findings were validated in a second, retrospective study, analyzing data of 383 Austrian ME/CFS patients with regard to MCA involvement and OI.

Results: Among followed-up ME/CFS patients, MCA prevalence increased over the disease course, with up to 25.3% meeting the criteria for clinically relevant MCA. ME/CFS patients with Mast Cell Activation Syndrome (MCAS) and OI reported symptom alleviation significantly more often following mast cell-targeted treatment than those without MCAS (p < 0.0001). With regard to IF-channel inhibitors, ME/CFS patients diagnosed with MCAS responded more frequently than those without MCAS (p = 0.076), while no significant differences were observed in response to beta blockers (p = 0.637). In both cohorts, OI, particularly POTS, was significantly more common in patients with MCA involvement.

Conclusions: MCA appears to be a frequent and clinically relevant comorbidity in ME/CFS and is associated with a higher prevalence of OI, particularly POTS. Stratifying patients based on MCA involvement may support personalized treatment approaches and improve clinical outcomes.

Source: Rohrhofer J, Ebner L, Schweighardt J, Stingl M, Untersmayr E. The Clinical Relevance of Mast Cell Activation in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Diagnostics (Basel). 2025 Nov 7;15(22):2828. doi: 10.3390/diagnostics15222828. PMID: 41300853; PMCID: PMC12651186. https://pmc.ncbi.nlm.nih.gov/articles/PMC12651186/ (Full text)

Autonomic symptom burden, comorbidities and quality of life in women with Hypermobility Spectrum Disorders and hypermobile Ehlers-Danlos syndrome

Abstract:

Background: Hypermobility Spectrum Disorders (HSD) and hypermobile Ehlers-Danlos syndrome (h-EDS) are multisystemic connective tissue disorders involving joint hypermobility and numerous other manifestations. Autonomic dysfunction, chronic pain, and chronic fatigue are known comorbidities of HSD and h-EDS that can affect patient quality of life (QoL), but there are limited data on the severity of autonomic symptoms, prevalence of comorbid conditions and QoL in patients with HSD/h-EDS.

Methods: We utilized the Composite Autonomic Symptom Scale (COMPASS-31) to assess autonomic symptom severity, Short-Form 36 (SF-36) to assess QoL, and the Beck Depression Inventory Second Edition (BDI-II) in a cohort of women with physician-diagnosed HSD or h-EDS, who completed these questionnaires anonymously.

Results: 84 women (mean age of 37.1 ± 8.4 years) completed the study. 58.3 % reported having physician-diagnosed postural orthostatic tachycardia syndrome (POTS), 32.1 % had mast cell activation syndrome (MCAS), 54.8 % had migraine, 26.2 % had myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and 98.8 % reported experiencing chronic pain. Importantly, 25 % of patients reported having all three diagnoses: HSD/h-EDS, POTS and MCAS. Mean COMPASS-31 score was 54.45 (range 18.79-80.93), indicating severe autonomic dysfunction, which was significantly higher than in patients with multiple sclerosis, diabetic neuropathy, scleroderma, and psoriatic arthritis as shown in prior studies. Mean SF-36 score was 32.38 (SD = 22.91) indicating poor QoL, which was worse than in patients with POTS, multiple sclerosis, rheumatoid arthritis, and lupus as determined by prior studies.

Conclusions: This study demonstrates that women with HSD/h-EDS experience severe autonomic dysfunction, chronic pain, chronic comorbid conditions and reduced QoL. More than half of participants in this cohort had POTS and migraine, with one in four having a clinical triad of HSD/h-EDS, POTS and MCAS.

Source: Collins Hutchinson ML, Liang E, Fuster E, Blitshteyn S. Autonomic symptom burden, comorbidities and quality of life in women with Hypermobility Spectrum Disorders and hypermobile Ehlers-Danlos syndrome. Auton Neurosci. 2025 Oct 14;262:103356. doi: 10.1016/j.autneu.2025.103356. Epub ahead of print. PMID: 41118678. https://pubmed.ncbi.nlm.nih.gov/41118678/

A Mechanical Basis: Brainstem Dysfunction as a Potential Etiology of ME/CFS and Long COVID

Abstract:
The underlying pathologies driving post-acute infectious syndromes (e.g. myalgic encephalomyelitis / chronic fatigue syndrome, long COVID, etc) remain poorly understood. Given the extreme burden these illnesses impose on suffers, and the dramatic increase in cases following the COVID-19 pandemic, it is important to establish a deeper understanding of these pathologies.
We propose a model of how ME/CFS (and related illnesses), might emerge following a viral insult. Central to this hypothesis is the recognition that the core diagnostic features of ME/CFS involve bodily systems known to be governed by the brainstem. This is consistent with the growing literature suggesting that spinal and craniocervical pathologies are over-represented in people with ME/CFS and other post-infectious disorders.
We hypothesize that a non-trivial number of cases of ME/CFS and Long Covid (LC) may have a “mechanical basis.” We propose that an infectious insult may trigger an initial loss of connective tissue integrity in susceptible individuals (e.g. those with pre-existing hypermobility spectrum disorders), which in turn leads to instability at the craniocervical junction, and ultimately mechanical deformation of the brainstem. This ultimately causes widespread autonomic nervous system and immune system dysfunction due to aberrant signaling from the deformed nuclei.
This causal chain may also lead to a vicious cycle: if the dysregulation produced by the initial brainstem deformation leads to a deranged immune response or state of chronic hyper-inflammation, further expression of connective tissue degrading and remodeling factors such as MMPs and mast cells may be triggered. This could further degrade the connective tissues of the craniocervical junction and, in turn, increase mechanical deformation of the brainstem, leading to symptom exacerbation over time and leading to the chronic, lifelong presentation typical of ME/CFS.
Source: Wood, J., Varley, T., Hartman, J., Melia, N., Kaufman, D., & Falor, T. (2025). A Mechanical Basis: Brainstem Dysfunction as a Potential Etiology of ME/CFS and Long COVID. Preprints. https://doi.org/10.20944/preprints202506.0874.v1 https://www.preprints.org/manuscript/202506.0874/v1 (Full text)

Mast Cells in the Autonomic Nervous System and Potential Role in Disorders with Dysautonomia and Neuroinflammation

Abstract:

Mast cells (MC) are ubiquitous in the body and are critical for allergic diseases, but also in immunity and inflammation, as well as potential involvement in the pathophysiology of dysautonomias and neuroinflammatory disorders. MC are located perivascularly close to nerve endings and sites such as the carotid bodies, heart, hypothalamus, the pineal and the adrenal glands that would allow them to regulate, but also be affected by the autonomic nervous system (ANS).

MC are stimulated not only by allergens, but also many other triggers including some from the ANS that can affect MC release of neurosensitizing, proinflammatory and vasoactive mediators. Hence MC may be able to regulate homeostatic functions that appear to be dysfunctional in many conditions, such as postural orthostatic hypertension syndrome (POTS), autism spectrum disorder (ASD), myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long-COVID syndrome.

The evidence indicates that there is a possible association between these conditions and diseases associated with mast cell activation, There is no effective treatment for any form of these conditions other than minimizing symptoms. Given the many ways MC could be activated and the numerous mediators released, it would be important to develop ways to inhibit stimulation of MC and the release of ANS-relevant mediators.

Source: Theoharides TC, Twahir A, Kempuraj D. Mast Cells in the Autonomic Nervous System and Potential Role in Disorders with Dysautonomia and Neuroinflammation. Ann Allergy Asthma Immunol. 2023 Nov 9:S1081-1206(23)01397-2. doi: 10.1016/j.anai.2023.10.032. Epub ahead of print. PMID: 37951572. https://pubmed.ncbi.nlm.nih.gov/37951572/

Mast cell activation may contribute to adverse health transitions in COVID-19 patients with frailty

Abstract:

A prominent aspect of the post-coronavirus disease-2019 (post-COVID-19) era is long-COVID. Therefore, precise patient classification and exploration of the corresponding factors affecting long-COVID are crucial for tailored treatment strategies. Frailty is a common age-related clinical syndrome characterized by deteriorated physiological functions of multiple organ systems, which increases susceptibility to stressors.

Herein, we performed an inclusion and exclusion analysis (definite COVID-19 infection diagnosis, clear underlying disease information, ≥60 years old, and repeated sampling of clinical cases) of 10,613 blood samples and identified frailty cases for further investigation. RNA-Seq data were used for differential gene expression and functional and pathway analyses.

The results revealed that patients with frailty were more prone to poor health conversions and more sequelae, and the blood transcriptome had obvious disturbances in pathways associated with immune regulation, metabolism, and stress response. These adverse health transitions were significantly associated with mast cell activation. Additionally, NCAPG, MCM10, and CDC25C were identified as hub genes in the peripheral blood differential gene cluster, which could be used as diagnostic markers of poor health conversion.

Our results indicate that healthcare measures should be prioritized to mitigate adverse health outcomes in this vulnerable patient group, COVID-19 patients with frailty, in post-COVID era.

Source: Xiangqi Li, Chaobao Zhang & Zhijun Bao (2023) Mast cell activation may contribute to adverse health transitions in COVID-19 patients with frailty, Emerging Microbes & Infections, 12:2, DOI: 10.1080/22221751.2023.2251589 https://www.tandfonline.com/doi/pdf/10.1080/22221751.2023.2251589 (Full text)

Long COVID, POTS, CFS and MTHFR: Linked by Biochemistry and Nutrition

Abstract:

The recent pandemic has energized research spotlighting chronic fatigue disorders. The similarities between Long COVID (LC) and Chronic Fatigue Syndrome (CFS), often accompanied by postural orthostatic tachycardia syndrome (POTS) are striking.

Furthermore, the majority afflicted with LC and CFS may be those with methylenetetrahydrofolate reductase (MTHFR) polymorphisms, present in the majority of Americans and characterized by hypomethylation. Elevated homocysteine (Hcy) and depressed B9 and B12 may be links. Speculation about an association between these laboratory analytes and MTHFR abnormalities has been previously reported (Regland et al., 2015).

The absence of a blood-brain barrier (BBB) in CNS circumventricular organs (CVOs) that control autonomic and neuroendocrine functions, problematic in LC, CFS, POTS, and MTHFR, is provocative. Diffusion of CNS Hcy is associated with brain fog, cognitive impairment, and dementia. This provides a distinct link between MTHFR variants and the fog of LC, CFS, and POTS.

Small intestine bacterial overgrowth (SIBO), present in about 17% of Americans, is linked to POTS, mast cell activation syndrome (MCAS), and Ehlers Danlos syndrome (EDS). All exhibit histamine intolerance and female predominance. This may be due to hypomethylation and/or intestinal diamine oxidase (DAO) deficiency.

Metabolism of monoamines and histamine requires methylation. Specific CNS nuclei in CVOs may also provide insight to the POTS paradox. The similar gut microbiomes of LC/CFS (and vitamin D deficiency) may via CVOs trigger an imbalance in glutamate/GABA neurotransmission that translates to neuroendocrine and baroreflex dysfunction. Homozygosity for the MTHFR 677T allele can facilitate hypermethylation via an alternative “rescue” riboflavin pathway triggered by significant Hcy increase.

Hypermethylation predominates in Long Covid. The primary problem in these syndromes is compromised mitochondrial function due to oxidative stress induced by an antioxidant shortfall.

Victims are also frequently deficient in 25(OH)D3 (the storage form of vitamin D), magnesium, and B vitamins, consumed by the persistent chronic inflammatory state. Estrogen increases histamine, norepinephrine, and bradykinin (BKN), which may in part explain the brain fog and its predilection for females.

Source: Patrick W Chambers. Long COVID, POTS, CFS and MTHFR: Linked by Biochemistry and Nutrition. Journal of Orthomolecular Medicine. 38. https://www.researchgate.net/publication/373073968_Long_Covid_POTS_CFS_and_MTHFR_Linked_by_Biochemistry_and_Nutrition#fullTextFileContent (Full text)

Antihistamines improve cardiovascular manifestations and other symptoms of Long-COVID attributed to Mast Cell Activation

Abstract:

Introduction: Long-COVID is a hardly defined condition and there are no effective therapies. Cardiovascular manifestations of Long-COVID include high heart rate, postural tachycardia, and palpitations. Previous studies have suggested that mast cell activation (MCA) may play a role in the pathophysiology of Long-COVID, including in the mechanisms of its cardiovascular manifestations. The aim of the study was to evaluate the effectiveness of a treatment with blockers of histamine receptors in Long-COVID patients who did not respond to other therapies.

Methods: Fourteen patients (F/M=9/5; 49.5±11.5 years) and 13 controls (F/M=8/5; 47.3±8.0 years) with Long-COVID symptoms attributed to MCA were evaluated. Patients were treated with fexofenadine (180 mg/day) and famotidine (40 mg/day). Fatigue, brain fog, abdominal disorders, and increased heart rate were evaluated in treated and untreated patients at baseline and 20 days later.

Results: Long-COVID symptoms disappeared completely in 29% of treated patients. There was significant improvement in each of the considered symptoms (improved or disappeared) in all treated patients, and the improvement grade was significantly greater in treated patients with respect to controls. No significant differences in the outcomes were observed in the controls.

Our data confirm that histamine receptors blockade may be an effective target to successfully treat long-COVID. Our finding supports the underlying role of MCA in the pathophysiology of Long-COVID.

Source: Fabrizio Salvucci, Roberto Codella, ADRIANA COPPOLA, Irene Zacchei, Gabriella Grassi, Maria L. Anti, Nicolita Nitisoara, Livio Luzi, and Carmine Gazzaruso. Antihistamines improve cardiovascular manifestations and other symptoms of Long-COVID attributed to Mast Cell Activation. Front. Cardiovasc. Med. Sec. General Cardiovascular Medicine. Volume 10 – 2023 | doi: 10.3389/fcvm.2023.1202696 https://www.frontiersin.org/articles/10.3389/fcvm.2023.1202696/abstract

Clinical Features of Post-Covid Syndrome

Abstract:

There is no common understanding of the clinical picture of post-covid syndrome. The US regulator CDC proposes to highlight:

(A) persistent symptoms and conditions that begin during acute COVID-19 illness;

B) new onset late complications after asymptomatic disease or a period of acute symptomatic relief or remission;

(C) the evolution of symptoms and conditions that include some persistent symptoms (eg, shortness of breath) with the addition of new symptoms or conditions over time (eg, cognitive difficulties).

Some manifestations may resemble other postviral syndromes such as myalgic encephalomyelitis/chronic fatigue syndrome, dysautonomia (eg, postural orthostatic tachycardia syndrome), or mast cell activation syndrome.

Source: Sayfulloyevich, P. S. ., & Musayevich, U. R. . (2023). Clinical Features of Post-Covid Syndrome. EUROPEAN JOURNAL OF INNOVATION IN NONFORMAL EDUCATION, 3(6), 34–36. Retrieved from http://inovatus.es/index.php/ejine/article/view/1786 http://inovatus.es/index.php/ejine/article/view/1786/1794 (Full text)

Long COVID is primarily a Spike protein Induced Thrombotic Vasculitis

Abstract:

Long COVID describes an array of often debilitating symptoms in the aftermath of SARS-CoV-2 infection, with similar symptomatology affecting some people post-vaccination. With an estimated > 200 million Long COVID patients worldwide and cases still rising, the effects on quality of life and the economy are significant, thus warranting urgent attention to understand the pathophysiology. Herein we describe our perspective that Long COVID is a continuation of acute COVID-19 pathology, whereby coagulopathy is the main driver of disease and can cause or exacerbate other pathologies common in Long COVID, such as mast cell activation syndrome and dysautonomia.
Considering the SARS-CoV-2 spike protein can independently induce fibrinaloid microclots, platelet activation, and endotheliitis, we predict that persistent spike protein will be a key mechanism driving the continued coagulopathy in Long COVID. We discuss several treatment targets to address the coagulopathy, and predict that (particularly early) treatment with combination anticoagulant and antiplatelet drugs will bring significant relief to many patients, supported by a case study. To help focus attention on such treatment targets, we propose Long COVID should be referred to as Spike protein Induced Thrombotic Vasculitis (SITV). These ideas require urgent testing, especially as the world tries to co-exist with COVID-19.

Source: Kerr R, Carroll HA. Long COVID is primarily a Spike protein Induced Thrombotic Vasculitis. Research Square; 2023. DOI: 10.21203/rs.3.rs-2939263/v1. https://assets.researchsquare.com/files/rs-2939263/v1_covered_7190a867-1475-4b57-b220-716a953649f1.pdf?c=1684433225 (Full text)