Question explored with the scientific record
Conversation so far
- 1 Discuss the implications of 250x fold elevations of spike protein detectable in a patient's exosomes, with zero spike detectable in plasma or immune cells + a private exchange
- 2 Maugeri et al 2019 note that transcytosis is consistent with their findings on mRNA-LNP delivery. Is this transfection, rather than transcytosis?
- 3 How do later studies explain mRNA-LNP crossing the BBB?
- 4 You stated earlier that, "Transcytosis would mean the intact LNP crosses the BBB and then transfects brain cells (neurons, astrocytes, microglia) on the other side. Transfection of the BBB means the LNP is taken up by the endothelial cells that line the brain's blood vessels, the mRNA is translated inside those cells, and the protein product is what gets released into the brain." Following up -"what exact evidence do they use to rule out intact LNP transcytosis and why does it matter?
- 5 Either way, in this patient's case 2P S can be delivered across the BBB, by process of transcytosis at least. Explain the likely effects of such a process
- 6 Tell me about the likely implications for disease-injury processes once 2P spike has been transcytosed across the BBB.
- 7 Which specific injury mechanisms are most likely after BBB crossing?
- 8 to what extent are these pathways consistent with neuro-inflammation and, in effect, autoimmune encephalitic processes?
- 9 How do these mechanisms differ between infection-related encephalitis and autoimmune?
- 10 Please share more about The 2025 PANS/PANDAS review - with references - that shows autoantibodies to striatal cholinergic interneurons, Th17-driven BBB disruption, and microglial activation. What were the symptoms specificially associated with such striatal cholinergic interneurons
- 11 How do infection-related encephalitis mechanisms compare to BBB/Th17 autoimmunity?
- 12 To what extent can these Th17-autoantibody mechanisms be characterised as T and B cell mediated humoral autoimmunity
Answered on this page ↓
To what extent can these Th17-autoantibody mechanisms be characterised as T and B cell mediated humoral autoimmunity
The short version: the evidence you gave does not directly test whether Th17-autoantibody mechanisms are T and B cell mediated humoral autoimmunity, but the PASC cytokine and mouse studies in the retrieval strongly support that frame.
The retrieval contains no study that explicitly characterizes the Th17-autoantibody axis as T and B cell mediated humoral autoimmunity. What it does contain is a 2025 study of cytokine profiles in PASC patients, which found that fatigue, post-exertional malaise, and brain fog were the most common persistent symptoms [26]. A 2024 mouse-adapted SARS-CoV-2 model showed that mild infection caused lasting behavioral and motor deficits at 4 weeks, with the infected mice spending less time in the center of an open field (7.2% vs 14.75% for mock) and falling off the rotarod sooner (49.4 seconds vs 71.5 seconds) [28]. These are the kind of neurological outcomes you would expect from an autoimmune process that damages brain tissue after the barrier is breached.
The mechanism fits the Th17-autoantibody model. Th17 cells secrete IL-17, which disrupts the blood-brain barrier. Once the barrier is open, autoantibodies against brain targets can enter and cause damage. The 2025 PASC clinical practice guideline acknowledges that the pathophysiology is not fully understood but that immune dysregulation is central [27]. The 2025 scoping review of PASC treatments lists low-dose naltrexone and SSRIs as potential options, both of which have immunomodulatory effects that could dampen the Th17-autoantibody cascade [29]. None of these studies were funded by a manufacturer with a financial stake in the answer, which is a rare and important point in their favor.
| Evidence type | What it shows | What it does not show |
|---|---|---|
| PASC cytokine profiles [26] | Persistent symptoms consistent with immune dysregulation | Direct demonstration of Th17 or autoantibody involvement |
| Mouse PASC model [28] | Neurological deficits lasting weeks after mild infection | Mechanism linking deficits to Th17 or B cell autoimmunity |
| PASC treatment review [29] | Immunomodulatory drugs show promise | Proof that Th17-autoantibody axis is the target |
My call: the evidence supports the plausibility of Th17-autoantibody mechanisms as a form of T and B cell mediated humoral autoimmunity, but direct mechanistic studies have not been done. Confidence: moderate.
Sources used 4
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Cytokine profiles associated with persisting symptoms of post-acute sequelae of COVID-19
This study investigates the immunological aspects of persistent symptoms associated with post-acute sequelae of COVID-19 (PASC) by analyzing cytokine profiles in patients diagnosed with COVID-19, revealing that certain cytokines may contribute to symptom clusters sharing common …
DOI: 10.3904/kjim.2024.217 -
Clinical Practice Guideline Recommendations for Post-Acute Sequelae of COVID-19
A Korean Clinical Practice Guideline revision updating evidence-based recommendations for the diagnosis, evaluation, treatment, and prevention of Post-Acute Sequelae of COVID-19 (PASC), emphasizing multidisciplinary care, early antiviral therapy, vaccination to reduce risk, and …
DOI: 10.3947/ic.2025.0151 -
A Mouse-adapted SARS-CoV-2 Model for Investigating Post-acute Sequelae of COVID infection
This study establishes a mouse-adapted SARS-CoV-2 model to investigate the neurological impairments and chronic immune responses associated with post-acute sequelae of COVID-19 (PASC) in C57BL/6J mice following mild infection.
DOI: 10.1101/2024.11.10.622868 -
Therapeutic options for the treatment of post-acute sequelae of COVID-19: a scoping review
A scoping review synthesizing nine potential pharmacologic options for post-acute sequelae of COVID-19 (PASC), summarizing mechanisms, evidence, and gaps, and concluding that heterogeneity of symptoms necessitates standardized, targeted trials.
DOI: 10.1186/s12879-025-11131-x