Emerging evidence supports the hypothesis that certain post-vaccination cardiomyopathies may result not from downstream inflammatory signaling alone, but from immune-mediated disruption of upstream regulatory architecture in critical cytokine networks leading to the downstream inflammatory signaling. Specifically, autoimmunity triggered by epitope mimicry or tolerance erosion may disable control points in the CXCL10/interferon-γ (IFN-γ) axis, resulting in chemokine-dominant inflammation and tissue-specific injury. This article reviews new experimental findings that validates predictive analyses suggesting that pathogenic priming may impair regulatory nodes including cytoplasmic kinases, phosphatases, antigen processing elements, and immune signal resolution components.Injury phenotypes like post-mRNA vaccine myocarditis are consistent with upstream regulatory failure, not merely exaggerated downstream response. The final missing piece of evidence, cross-reactive T-cells and autoantibodies, should be studied in patients with COVID-19 vaccine-induced myocarditis. Such evidence has been found for heart proteins; one spike epitope mimicking a peptide sequence from a cardiomyocyte-expressed K+ channel (Kv2). Functional responses to Kv2 show an expanded cytokine-production pattern in post‑vaccine AMP not seen in a COVID‑19 cohort, with an autoimmune signature segregates to cardiotropic cMet+ T cells and is prevented by cMet inhibition

The phenomenon of pathogenic priming—a form of maladaptive immune memory caused by molecular mimicry between pathogen-derived antigens and human proteins—has been proposed as a possible mechanism for a subset of post-vaccination adverse events. Recent work, including a preclinical study published in Science Translational Medicine (Cao et al., 2025), has identified persistent expression of CXCL10 and IFN-γ following second-dose exposure to SARS-CoV-2 spike mRNA vaccination in mice, leading to cardiac inflammation and impaired contractility [1]. The elevated CXCL10/IFN-γ signature suggests dysfunction of immune regulatory feedback mechanisms.

New Mechanistic Insight

The original article on pathogenic priming (Lyons-Weiler, 2020) mapped multiple SARS-CoV-2 immunogenic epitopes to human proteins that serve as upstream regulators in immune signaling [2]. These included:

• BMX: A cytoplasmic tyrosine kinase known to modulate STAT1 signaling

• PHLPP1: A phosphatase regulating AKT and inflammatory thresholds

• PSMC4: A proteasomal subunit essential for MHC-I antigen processing

• LARP4: An RNA-binding protein involved in transcript stability of immune-related genes

Autoimmunity directed against these proteins would remove key brakes on inflammation and alter the fidelity of antigen processing, leading to compensatory cytokine excess.

Pathway-Level Consequences

Disruption of upstream regulators leads to the following cascade:

1. Impaired antigen discrimination due to proteasomal or TAP dysfunction

2. Poor IFN-α/β induction due to MAVS or IRF silencing

3. Compensatory overexpression of IFN-γ and ISGs such as CXCL10

4. Tissue infiltration and injury, especially in endothelial and myocardial tissue

These processes are not caused by direct toxicity of the spike protein per se, but by regulatory distortion resulting from the immune system’s misrecognition of homologous self-epitopes.

Post‑mRNA vaccination autoimmune myopericarditis: direct evidence of spike–self cross-reactive T cells

The results have high clinical relevance, pointing to multimodal injury. Fanti et al. (2025) report that T cells from patients who developed acute myopericarditis (AMP) after mRNA vaccination recognize spike epitopes homologous to cardiac self‑proteins, and they identify a spike epitope mimicking a peptide sequence from a cardiomyocyte-expressed K+ channel (Kv2). They report that functional responses to Kv2 show an expanded cytokine-production pattern in post‑vaccine AMP not seen in their COVID‑19 cohort, and that the autoimmune signature segregates to cardiotropic cMet+ T cells and is prevented by cMet inhibition.

They describe the explicit molecular mimicry test: challenge with the autologous Kv2.1-derived peptide and measurement of proliferative and cytokine responses in patient PBMCs, framed as establishing mimicry in the context of spike exposure.

This is, by the standard definition, evidence of pathogenic priming leading to cross-reactive T‑cell autoimmunity in a post‑vaccination cardiomyopathy phenotype.

Numerous autoimmune conditions have been seen to emerge following COVID-19 vaccination (Peng et al., 2025) in a pattern that suggests a common trigger.

Our mechanism may explain why myocarditis cases appear more frequently after the second mRNA dose, consistent with memory-driven amplification of maladaptive pathways. Importantly, these events may not be dose-dependent but instead reflect priming thresholds crossed by repeated exposure. In this model, cardiac autoimmunity is not the result of classic autoantibody production, but of loss of control in regulatory circuits governing cytokine signaling.

Vague and difficult-to-diagnose syndromes that follow vaccination of any type should be studied for the effects of de novo autoreactogenic immunity.

Treatments and therapies that do not consider upstream factors downregulated by autoimmunity will fail to resolve chronic illness.

Figure 1. Disruption of upstream immune regulators and its role in CXCL10/IFN-γ-driven myocarditis following COVID-19 vaccination,. This represents one pathways by which pathogenic priming can induce myocarditis..

Autoantibodies and autoreactive T cells triggered by molecular mimicry impair key upstream regulators—including MAVS, BMX kinase, proteasome subunits (e.g., PSMC4), and phosphatases like PHLPP1—leading to suppressed type I interferon (IFN-α/β) signaling and compensatory overactivation of IFN-γ and CXCL10. This cytokine dysregulation promotes immune cell infiltration, endothelial dysfunction, and myocardial damage, culminating in vaccine-associated cardiomyopathy. Diagram integrates both innate and adaptive immune disruption, highlighting feedback failure as central to pathogenic priming.

Definitive Testing of the Pathogenic Priming Hypothesis via Autoimmunity Mapping

The most decisive test of the hypothesis that upstream regulators of immune signaling are disrupted via pathogenic priming is the direct detection of autoreactive immune components—specifically, autoreactive T cells and autoantibodies directed against key regulatory proteins such as BMX kinase, MAVS, PHLPP1, IRF7, and PSMC4. Identification of such immune responses in individuals with post-vaccine or post-COVID chronic illness would provide conclusive evidence that the observed cytokine dysregulation (e.g., IFN-γ and CXCL10 elevation) arises not from persistent antigen presence, but from immune system misrecognition of self.

TITIN, the largest protein in the human protein, is also found in the heart. It is a predicted target (Lyons-Weiler, 2020) and autoreactive antibodies should be sought in cases and deaths related to myocarditis following SARS-CoV-2 vaccination.

These tests are technically feasible. ELISPOT assays, intracellular cytokine staining, or tetramer-guided T cell profiling can detect CD4+ and CD8+ T cell reactivity against synthetic peptides matching these human proteins. Similarly, protein microarrays and linear epitope mapping via phage display can uncover circulating IgG or IgA autoantibodies targeting these intracellular regulatory components. These methods have been used to confirm molecular mimicry in other autoimmune conditions, including Guillain–Barré syndrome and narcolepsy.

Given the widespread and persistent reports of chronic symptoms following SARS-CoV-2 infection or vaccination—including fatigue, post-exertional malaise, POTS, myocarditis, neuropathy, and dysautonomia—autoimmune profiling in these individuals is not merely warranted, it is essential. A properly powered study comparing chronic symptom sufferers post-COVID or post-vaccine to matched controls would clarify whether the immune system has indeed misidentified and begun attacking its own regulatory proteins. If such autoreactivity is observed, it would validate the core premise of pathogenic priming and provide an urgent rationale for screening, prediction, and therapeutic intervention based on autoantigen profiles.

Such investigations will also help stratify chronic post-COVID or post-vaccine syndromes into distinct mechanistic subtypes: those driven by residual viral debris, those driven by microbiome disturbance, and those driven by autoimmune disruption of signal control points. This would replace the vague language of “Long COVID” and “vaccine injury” with actionable pathophysiological classifications grounded in molecular evidence.

Conclusion

Pathogenic priming leading to iatrogenic disease in humans is now a priority clinical research area. As converging experimental, computational, and clinical data suggest, epitope-driven disruption of upstream immune regulators may underlie CXCL10/IFN-γ-driven cardiomyopathy in a subset of post-vaccine adverse events. Recognition of this mechanism provides a critical pathway-specific target for monitoring, mitigation, and therapeutic intervention.

Future vaccines must not be allowed to include epitopes that are predicted to be unsafe epitopes.

References

[1] Cao X, et al. Inhibition of CXCL10 and IFN-γ ameliorates myocarditis in preclinical models of SARS-CoV-2 mRNA vaccination. Sci Transl Med. 2025; doi:10.1126/scitranslmed.adq0143.

[2] Lyons-Weiler J. Pathogenic priming likely contributes to serious and critical illness and mortality in COVID-19 via autoimmunity. J Transl Autoimmun. 2020;3:100051. doi:10.1016/j.jtauto.2020.100051.

[3] Fanti S, Dyer C, Ingimarsdóttir IJ, Harding D, Wang G, D’Amati A, Shahaj E, Sigurbergsdóttir AÝ, Thórsdóttir H, Gunnarsdóttir OB, Kanoni S, Wright P, Martin J, Chorlton J, Hollowood Z, Brynjólfsson SF, Lúdvíksson BR, Solito E, Bert S, Keane JM, Mohiddin SA, Longhi MP, Marelli-Berg FM. Combined Adaptive Immune Mechanisms Mediate Cardiac Injury After COVID-19 Vaccination. Circulation. 2025 Nov 25;152(21):1485-1500. https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.125.074644

[4] Peng M, Wang Z. Vaccine-Associated Autoimmunity: From Clinical Signals to Immune Pathways. Vaccines. 2025; 13(11):1112. https://doi.org/10.3390/vaccines13111112

 

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