Immune dysfunction / autoimmune activation
Persistent immune dysregulation or autoantibodies driving inflammation and downstream symptoms.
Persistent immune activation, cytokine abnormalities, and functional autoantibodies (e.g. against G-protein-coupled receptors) are among the better-supported biological findings, but no treatment is yet established. The well-designed trials have largely been null — colchicine, the BC007 autoantibody-neutralizing aptamer (company phase II), and leronlimab all disappointed. Low-dose naltrexone is the lowest-risk option with real patient interest and trials ongoing (prioritized by RECOVER-TLC); low-dose rapamycin and baricitinib are in trials. IVIG should be reserved for objectively confirmed autoimmune small-fiber neuropathy, given cost and risk.
How it's tested
Inflammatory markers (CRP, cytokine profile)
CRP is cheap and widely available; a fuller cytokine profile is pricier. Elevated markers support ongoing immune activation.
Autoantibody panel (incl. GPCR autoantibodies)
Functional autoantibodies against G-protein-coupled receptors and others. Commercially available but not validated as a clinical diagnostic.
Treatment options & their evidence
Graded honestly — including treatments that failed in good trials, which is worth knowing.
IVIG (intravenous immunoglobulin)
Mixed evidenceSerious harm riskOpen-label/case-series benefit in confirmed autoimmune small-fiber neuropathy, but a randomized trial for idiopathic small-fiber pain was negative — reserve for objectively confirmed autoimmune cases.
Caution: Thromboembolism, aseptic meningitis, renal injury, anaphylaxis; very expensive and supply-limited.
Low-dose naltrexone (LDN)
Weak evidenceThe lowest-risk option in the immune cluster: observational pre-post studies show fatigue improvement; no completed RCT yet, but several are ongoing (prioritized by RECOVER-TLC).
Caution: Vivid dreams, insomnia; contraindicated with opioid use.
Low-dose rapamycin / sirolimus
Anecdotal onlyCautionStrong mechanistic rationale (restoring autophagy); only small uncontrolled pilots so far, with RCTs in progress and no efficacy readout.
Caution: Immunosuppression, mouth ulcers, dyslipidemia, impaired wound healing.