Christoforou 2026 — High-dose continuous-regimen cromolyn in ME/CFS+MCAS

One-paragraph summary

Retrospective case series of 5 ME/CFS patients with comorbid Mast Cell Activation Syndrome (MCAS) treated with a non-standard cromolyn regimen: continuous oral dosing throughout the day (entire daily dose dissolved in opaque bottle of water, sipped over the day) at 1600–2400 mg daily — 2-3× higher than the conventional 800 mg/d maximum but within FDA safety guidelines. All 5 patients benefited from the higher continuous-dose regimen after the conventional 800 mg/d four-discrete-doses protocol was tolerated but ineffective. The authors propose theoretical advantages of continuous dosing (steady-state mast cell stabilization vs four pulse exposures with troughs) but acknowledge n=5 retrospective design limitations. Critical for the H2 hypothesis salvage: this paper provides a path forward for the MC-stabilization arm after Ang 2014's negative ketotifen RCT — different agent (cromolyn vs ketotifen), substantially higher dose, different administration regimen, and crucially subtype-stratified inclusion (MCAS comorbidity required). The H2 chain that Ang 2014 weakened in its all-comers form is now plausibly tenable in MCAS-stratified high-dose continuous-cromolyn trials.

Claims as triples

• me_cfs — responds_to → cromolyn [evidence: 5/5 ME/CFS+MCAS responders to high-dose continuous regimen; confidence: emerging]
• mast_cell — modulates → fatigue [evidence: MCAS-targeted treatment improved ME/CFS fatigue; confidence: emerging]

Methods note

Retrospective case series, n=5, ME/CFS+MCAS comorbidity required for inclusion. Cromolyn 1600-2400 mg/d (escalated from 800 mg/d) administered as continuous sip throughout day. Outcome assessed by clinical response, not standardized scales. Authors: Johns Hopkins (Rowe lab) — established ME/CFS clinical research group.

Limitations

• n=5, retrospective, no control group, no randomization, no quantitative outcome measure. Effect size unknown; placebo response cannot be excluded.
• ME/CFS, not FM. Direct extrapolation requires the MC-mediated mechanism to operate similarly in FM (which Morcos & Theoharides 2026 supports cross-condition).
• Selection bias: patients who failed standard-dose cromolyn and were willing to escalate may not be representative of all MC-active patients.
• "Effective" is unspecified — clinically improved on global impression vs domain-specific outcome measures.
• The continuous-dosing rationale is theoretical (steady-state vs pulse) but not empirically tested vs equal-total-dose discrete-administration.

Open questions raised

• Would continuous high-dose cromolyn show effect in MCAS-stratified FM specifically (vs ME/CFS)?
• Is the mechanism truly "more steady-state stabilization" or alternative (better intestinal absorption with sipping, gut MC effect from continuous luminal exposure)?
• What's the right sample size + outcome design for an RCT in MCAS-stratified ME/CFS or FM with this regimen?
• Does response to high-dose cromolyn correlate with HERV-W ENV positivity (HERV-W ENV is a TLR4 ligand that activates MCs) — bridging to the viral-genome-modification framework?

Triangulation notes

• Most consequential implication: the H2 hypothesis is salvageable. The asymmetric-priors update following Ang 2014 (causal-chain-hypotheses.md §5) reduced H2's expected fraction of FM. Christoforou 2026 doesn't contradict that — but provides a path forward for the MCAS-active subset that Ang 2014 didn't isolate. Specifically: the right H2 trial design is (a) MCAS-stratified inclusion, (b) high-dose continuous regimen, (c) cromolyn or analogous pharmacology, not 800 mg/d four-discrete-doses ketotifen in all-comers FM.
• Reinforces the project's broader subtype-stratification thesis: the same intervention class (MC stabilizer) that fails in unstratified populations may succeed in stratified subgroups.
• Paired with Wang 2025 (mast-cell + estrogen → pain sensitization, ingested concurrently), provides converging evidence that MC activation drives pain sensitization through specific molecular paths (histamine + FGF2 to dorsal horn neurons), and that interrupting MC activity at the cellular level (cromolyn) alleviates symptoms in MC-stratified patients.

Bridges

• B6 strengthened: ME/CFS responds to MC stabilization in the MCAS-active subset, suggesting the same cellular axis operates across FM/ME-CFS/long COVID.
• Q24 (anti-SGC IgG vs MC-active overlap) made more important: if MCAS-active responders to cromolyn are the same patients as anti-SGC-IgG-positive responders to daratumumab, the H1 and H2 chains converge mechanistically. If different patients, they're parallel cure-paths.