Fibromyalgia: H1 × H2 unified mechanism
Chain · evidence weight per link · disruption points — anchored on Sanchez/Goebel/Dong 2025 (bioRxiv preprint)
established
emerging
inferred
bridging
intervention break-point
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H1 × H2 unified mechanism — vertical flow
read top to bottom · arrow style encodes evidence tier · ① – ⑥ are intervention break-points
Gut dysbiosis
microbial SCFA / BA shifts
trigger
Viral / HERV
SARS-CoV-2 · EBV · HERV-W
trigger
Stress / trauma
HPA-axis activation
trigger
1
Bile acid elevation
Jakobsson 2026 — 24 BAs ↔ anti-SGC IgG
emerging
B-cell / plasma cell
activation · Talwar 2025 (LC)
emerging
2
FM-IgG (circulating pathogenic IgG)
Goebel 2021 passive transfer · Krock 2023 titer ↔ severity
Seefried 2025 — 37% of FM positive · Hanani 2026 multi-ganglia
emerging
★ FM-IgG → MRGPRX2 — Sanchez 2025
Mrgprb2 KO or MC ablation each
abolish IgG-pain phenotype
3
4
Substance P (CSF↑ in FM)
established biomarker
MC-SP loop via MRGPRX2 / NK1R
established · Aitella 26
5
HαT (TPSAB1↑) — amplifier
↑MC count · ↑MRGPRX2
Lyons 19 · Simeone 26
inferred · ~5% pop
MAST CELL + MRGPRX2
★ H1 × H2 convergence node
Multiple ligands converge on one receptor:
FM-IgG · Substance P · HαT amplification
★ click for the full story
6
MC mediators released
IL-6 · histamine · tryptase · TNF-α · chymase
established
Estrogen ↑
at gfWAT (lipedema)
bridging · Amato 26
Satellite glia + sensory neuron sensitization
multi-ganglia: DRG · trigeminal · nodose · sympathetic (Hanani 26)
central sensitization machinery: NMDA-LTP · glial cytokines
emerging (multi-ganglia) + established (CS machinery)
Widespread pain
core FM phenotype
established
Multimodal hypersensitivity
pressure · temp · light · sound · odor
established
Long-COVID extension — Mignolet 2026 (Acta Neuropathologica)
LC-IgG passive transfer → DRG → sensory pain (no cognitive transfer)
structurally mirrors Goebel paradigm in PASC — predicts MRGPRX2 mechanism extends to post-COVID FM (Q78)
bridging · cross-condition
Six intervention break-points — click any numbered red circle above
① FMT/colesevelam · ② daratumumab · ③ FcRn block / plasmapheresis+IVIG · ④ ★ barzolvolimab (MRGPRX2) · ⑤ aprepitant (NK1R) · ⑥ cromolyn
★ ④ is the new intervention class unlocked by Sanchez 2025 — Phase 2/3 chronic urticaria, no IND barrier for FM repurposing