Schizophrenia - Autoantibody Parallels to ME/CFS

1 Dalmau et al. 2008 — Anti-NMDA-Receptor Encephalitis: Landmark Discovery

Full Citation:: Dalmau J, Gleichman AJ, Hughes EG, et al. Anti-NMDA-receptor encephalitis: case series and analysis of the effects of antibodies. The Lancet Neurology. 2008;7(12):1091–1098. DOI:: 10.1016/S1474-4422(08)70224-2 PMID:: 18851928 Published:: December 2008 Study Design:: Case series + in vitro mechanistic study Sample Size:: 100 patients with anti-NMDAR encephalitis Key Findings::

- 100 patients, 91% female, median age 23; 59% with ovarian teratoma
- All presented with psychiatric symptoms; 76% seizures, 88% unresponsiveness, 86% dyskinesias, 69% autonomic instability, 66% hypoventilation
- Antibodies target NR1 subunit N-terminal domain; cause NMDAR internalization and clustering loss — reversible by Ab removal
- Early tumor removal + immunotherapy → better outcome (p=0.004), fewer relapses (p=0.009)

Conclusion:: Anti-NMDAR encephalitis defines a treatable autoimmune condition presenting primarily with psychiatric symptoms — autoantibodies can cause reversible “psychosis.” Limitations:: Referral bias; no control group; predominantly young female with teratoma — different from idiopathic schizophrenia demographics. Certainty:: 0.90/1.0 Research Stream:: schizophrenia-autoantibodies

2 Ezeoke et al. 2013 — Blood Autoantibodies in Schizophrenia: Systematic Review

Full Citation:: Ezeoke A, Mellor A, Buckley P, Miller B. A systematic, quantitative review of blood autoantibodies in schizophrenia. Schizophrenia Research. 2013;150(1):245–251. DOI:: 10.1016/j.schres.2013.07.029 PMID:: 23953827 Published:: October 2013 Study Design:: Systematic quantitative review Sample Size:: 81 studies (of 111 identified) Key Findings::

- 20 different autoantibodies significantly elevated in schizophrenia vs controls
- Anti-cardiolipin IgG and NMDAR titers increased in first-episode psychosis (p\<0.01)
- Anti-cardiolipin IgG/IgM and NGF absolute titers elevated (p\<0.02)
- Marked study heterogeneity; inconsistent clinical-autoantibody correlations

Conclusion:: Schizophrenia is associated with increased prevalence of multiple autoantibodies, but heterogeneity and inconsistent correlations limit interpretation. Limitations:: No standardized assay methodology; publication bias; medication confounds; BMI and smoking rarely controlled. Certainty:: 0.72/1.0 Research Stream:: schizophrenia-autoantibodies

3 Pollak et al. 2014 — Prevalence of Anti-NMDAR Antibodies: Meta-Analysis

Full Citation:: Pollak TA, McCormack R, Peakman M, Nicholson TR, David AS. Prevalence of anti-N-methyl-D-aspartate (NMDA) receptor antibodies in patients with schizophrenia and related psychoses: a systematic review and meta-analysis. Psychological Medicine. 2014;44(12):2475–2487. DOI:: 10.1017/S003329171300295X PMID:: 24330811 Published:: September 2014 Study Design:: Systematic review and meta-analysis Sample Size:: 7 studies, 1441 patients Key Findings::

- 7.98% anti-NMDAR antibody positive (all Ig classes; 95% CI 6.69–9.50)
- Only 1.46% positive for IgG subclass (95% CI 0.94–2.23) — the pathogenic subclass
- Greater prevalence in cases vs controls only for IgG; IgA/IgM of uncertain relevance
- Significant heterogeneity in assays, patient characteristics, thresholds

Conclusion:: A minority of psychosis patients have NMDAR antibodies. IgG subclass specificity is critical. Limitations:: Serum only; variable assay sensitivity/specificity; small number of studies; mostly cross-sectional. Certainty:: 0.78/1.0 Research Stream:: schizophrenia-autoantibodies

4 Pearlman & Najjar 2014 — NMDAR Antibodies Across Psychiatric Disorders

Full Citation:: Pearlman DM, Najjar S. Meta-analysis of the association between N-methyl-D-aspartate receptor antibodies and schizophrenia, schizoaffective disorder, bipolar disorder, and major depressive disorder. Schizophrenia Research. 2014;157(1-3):249–258. DOI:: 10.1016/j.schres.2014.05.001 PMID:: 24882425 Published:: August 2014 Study Design:: Meta-analysis Sample Size:: 9 studies, 3387–3194 participants Key Findings::

- OR 3.10 for NMDAR-Ab seropositivity (high-specificity thresholds)
- NR2A/NR2B titers elevated in first-episode schizophrenia and acute mania
- Titers declined 58% over 8 weeks in first-episode schizophrenia

Conclusion:: Individuals with psychiatric disorders are ~3× more likely to have NMDAR antibodies by high-specificity assays. Temporal titer decline suggests state-dependent production. Limitations:: Heterogeneous thresholds; ELISA vs CBA discrepancies; serum only. Certainty:: 0.75/1.0 Research Stream:: schizophrenia-autoantibodies

5 Schou et al. 2016 — Anti-Neuronal Autoantibodies in Acute Psychiatry

Full Citation:: Schou M, Sæther SG, Borowski K, et al. Prevalence of serum anti-neuronal autoantibodies in patients admitted to acute psychiatric care. Psychological Medicine. 2016;46(16):3303–3313. DOI:: 10.1017/S0033291716002038 PMID:: 27609625 Published:: December 2016 Study Design:: Cross-sectional cohort Sample Size:: 925 unselected acute psychiatric admissions Key Findings::

- 11.6% had anti-neuronal autoantibodies: NMDAR 7.6%, CASPR2 2.5%, GAD65 1.9%
- Only 0.5% had NMDAR IgG — the pathogenic subclass
- NMDAR antibodies equally prevalent in psychosis and non-psychosis patients

Conclusion:: Anti-neuronal autoantibodies are common in acute psychiatry but IgG subclass (pathogenic) is rare. No diagnostic specificity for psychosis. Limitations:: Single Norwegian center; serum only; no CSF confirmation; indirect immunofluorescence may have limited sensitivity. Certainty:: 0.80/1.0 Research Stream:: schizophrenia-autoantibodies

6 Grain et al. 2017 — VGKC and GAD65 in Psychosis

Full Citation:: Grain R, Lally J, Stubbs B, et al. Autoantibodies against voltage-gated potassium channel and glutamic acid decarboxylase in psychosis: a systematic review, meta-analysis, and case series. Psychiatry and Clinical Neurosciences. 2017;71(10):678–689. DOI:: 10.1111/pcn.12543 PMID:: 28573688 Published:: October 2017 Study Design:: Systematic review, meta-analysis, case series Sample Size:: 5 VGKC studies + 9 GAD65 studies Key Findings::

- VGKC: 1.5% prevalence in psychosis vs 0.7% controls
- GAD65: 5.8% pooled prevalence; OR 2.24 vs controls (p=0.005)
- I²=91% — extreme heterogeneity across studies
- Few studies controlled for comorbid type 1 diabetes (inflating GAD65 estimates)
- 21 treatment-resistant cases: zero VGKC antibodies

Conclusion:: GAD65 autoantibodies are ~2× more common in psychosis but estimates likely inflated by undiagnosed diabetes. Limitations:: Extreme heterogeneity; diabetes comorbidity not controlled; variable titer thresholds. Certainty:: 0.68/1.0 Research Stream:: schizophrenia-autoantibodies

7 Cox et al. 2020 — Apheresis Trials in Schizophrenia: Historical Negative

Full Citation:: Cox ER, Marwick KFM, Hunter RW, Priller J, Lawrie SM. Dialysis and plasmapheresis for schizophrenia: a systematic review. Psychological Medicine. 2020;50(8):1233–1240. DOI:: 10.1017/S0033291720001324 PMID:: 32404224 Published:: June 2020 Study Design:: Systematic review of controlled trials Sample Size:: 9 studies, 105 patients total Key Findings::

- Hemodialysis: 6/8 no effect, 1 beneficial, 1 harmful
- 1 plasmapheresis trial: no benefit
- 23% adverse event rate
- No studies selected patients by autoantibody status

Conclusion:: Historical apheresis trials in unselected schizophrenia failed — directly analogous to early ME/CFS IVIG/apheresis trials. Limitations:: Small samples; old studies (1970s–80s); no biomarker-based stratification. Certainty:: 0.65/1.0 Research Stream:: schizophrenia-autoantibodies

8 Chaudhry et al. 2020 — Methotrexate RCT in Psychosis

Full Citation:: Chaudhry IB, Husain MO, Khoso AB, et al. A randomised clinical trial of methotrexate points to possible efficacy and adaptive immune dysfunction in psychosis. Translational Psychiatry. 2020;10:415. DOI:: 10.1038/s41398-020-01095-8 PMID:: 33257661 Published:: November 2020 Study Design:: RCT (12 weeks) Sample Size:: 92 participants Key Findings::

- Positive symptoms improved more with methotrexate (β=-2.5; 95% CI -4.7 to -0.4)
- No effect on negative symptoms
- No immune biomarkers measured; no autoantibody-based subgroup selection

Conclusion:: Methotrexate may improve positive symptoms. Future trials must use autoantibody-defined subgroups. Limitations:: Feasibility study; unselected; no immune biomarker stratification; short duration. Certainty:: 0.60/1.0 Research Stream:: schizophrenia-autoantibodies

9 Endres et al. 2020 — Autoantibody-Associated Psychiatric Syndromes: 145 Cases

Full Citation:: Endres D, Maier V, Leypoldt F, et al. Autoantibody-associated psychiatric syndromes: a systematic literature review resulting in 145 cases. Psychological Medicine. 2020;52(6):1135–1146. DOI:: 10.1017/S0033291720002895 PMID:: 32892761 Published:: September 2020 (online) Study Design:: Systematic review of case reports/series Sample Size:: 145 patients with autoimmune encephalitis mimicking psychiatric syndromes Key Findings::

- 55% cell-surface antibodies; most common: anti-NMDAR (n=46)
- 34% schizophreniform, 39% amnestic presentations
- CSF pathology: 78%; EEG: 61%; MRI: 51%
- 87% received immunotherapy; 94% responded — critical proof that Ab-selected treatment works

Conclusion:: Autoimmune encephalitis can mimic schizophrenia. Immunotherapy is highly effective when autoantibody-positive subgroup is identified (94% response). Limitations:: Publication bias toward positive outcomes; no control group. Certainty:: 0.78/1.0 Research Stream:: schizophrenia-autoantibodies

10 Ermakov et al. 2022 — Immune Abnormalities in Schizophrenia: ~1/3 Inflammatory

Full Citation:: Ermakov EA, Melamud MM, Buneva VN, Ivanova SA. Immune System Abnormalities in Schizophrenia: An Integrative View and Translational Perspectives. Frontiers in Psychiatry. 2022;13:880568. DOI:: 10.3389/fpsyt.2022.880568 PMID:: 35546942 Published:: April 2022 Study Design:: Systematic review Sample Size:: N/A Key Findings::

- All immune components affected: innate to adaptive, humoral to cellular
- Signs of severe inflammation in only ~1/3 of patients
- CRP, cytokines, neutrophils, autoantibodies, microbiota: lowest bias evidence
- Direct parallel to ME/CFS: only a subset has elevated inflammatory markers

Conclusion:: Inflammation in ~1/3 of schizophrenia — immunological parameters may identify treatment-responsive subgroups, as proposed for ME/CFS. Limitations:: Narrative elements; no quantitative meta-analysis. Certainty:: 0.75/1.0 Research Stream:: schizophrenia-autoantibodies

11 Hansen et al. 2023 — Glucocorticoids for Autoantibody-Associated Psychiatric Disease

Full Citation:: Hansen N, Neyazi A, Lüdecke D, et al. Repositioning synthetic glucocorticoids in psychiatric disease associated with neural autoantibodies: a narrative review. Journal of Neural Transmission. 2023;130(8):1029–1038. DOI:: 10.1007/s00702-022-02578-2 PMID:: 36576564 Published:: August 2023 Study Design:: Narrative review Sample Size:: N/A Key Findings::

- No RCTs of glucocorticoids for Ab-associated psychiatric disease
- Cohort data: beneficial response for cell-surface (membrane) antibody targets
- Less effective for intracellular antigen targets
- sGCs used as monotherapy or polytherapy with other immunosuppressants

Conclusion:: Glucocorticoids may benefit Ab-associated psychiatric disease. Target antigen location (membrane vs intracellular) predicts response — parallel for ME/CFS GPCR AABs (membrane targets). Limitations:: Narrative review; no systematic search; mostly case series. Certainty:: 0.65/1.0 Research Stream:: schizophrenia-autoantibodies

12 Luykx et al. 2024 — Clinical Profile of NMDAR-Seropositive Schizophrenia

Full Citation:: Luykx JJ, Visscher R, Winter-van Rossum I, et al. Clinical symptoms and psychosocial functioning in patients with schizophrenia spectrum disorders testing seropositive for anti-NMDAR antibodies. The Lancet Psychiatry. 2024;11(10):828–838. DOI:: 10.1016/S2215-0366(24)00249-9 PMID:: 39300641 Published:: October 2024 Study Design:: Case-control (4 European cohorts) Sample Size:: 1114 patients (41 seropositive, 3.7%) Key Findings::

- 3.7% seropositive (range 3.1–4.0% across 4 cohorts)
- NMDAR+ patients had LESS severe negative symptoms (d=0.36, p=0.026)
- Better psychosocial functioning (d=0.52, p=0.014)
- Live cell-based assay used (optimal specificity)

Conclusion:: NMDAR antibodies in schizophrenia (3–4%) are associated with milder symptoms and better functioning. May represent a distinct illness subtype. Limitations:: Serum only (no CSF); only IgG tested; European cohorts. Certainty:: 0.75/1.0 Research Stream:: schizophrenia-autoantibodies

13 Pluvinage et al. 2024 — Phage Display (REAP) Identifies Novel Autoimmune Neurologic Condition

Full Citation:: Pluvinage JV, Ngo T, Fouassier C, et al. Transcobalamin receptor antibodies in autoimmune vitamin B12 central deficiency. Science Translational Medicine. 2024;16(753):eadl3758. DOI:: 10.1126/scitranslmed.adl3758 PMID:: 38924428 Published:: June 2024 Study Design:: Discovery case + cohort validation + mechanistic Sample Size:: Index case + 132 paired serum/CSF samples Key Findings::

- Programmable phage display (REAP) identified anti-CD320 autoantibody causing neurologic deficits despite normal serum B12
- Impaired cellular B12 uptake by depleting CD320 from cell surface
- Prevalence: 6% of HC, 21.4% of neuropsychiatric lupus
- Immunosuppression + high-dose B12 → clinical improvement
- Unbiased screening discovered a mechanism missed by targeted testing

Conclusion:: Unbiased phage display identifies novel autoimmune mechanisms missed by targeted testing. Prototype for ME/CFS application. Limitations:: n=1 discovery; 6% healthy seroprevalence suggests not all anti-CD320 are pathogenic. Certainty:: 0.80/1.0 Research Stream:: schizophrenia-autoantibodies

14 Tebartz van Elst et al. 2025 — Neuropsychiatric Checklist for Autoimmune Psychosis

Full Citation:: Tebartz van Elst L, Runge K, Meyer PT, et al. The Neuropsychiatric Checklist for Autoimmune Psychosis: A Narrative Review. Biological Psychiatry. 2025;98(9):654–669. DOI:: 10.1016/j.biopsych.2025.02.889 PMID:: 39987981 Published:: November 2025 Study Design:: Narrative review with clinical tool Sample Size:: N/A Key Findings::

- Systematic integration of possible/probable/definite autoimmune psychosis criteria
- Red-flag symptoms: subacute onset, catatonia, seizures, autonomic instability
- FDG-PET most sensitive; CSF cell-surface Abs; EEG slowing; MRI
- Presents Neuropsychiatric Checklist for clinical assessment

Conclusion:: Structured diagnostic approach enables identification of immunotherapy-responsive patients. Potential model for autoimmune ME/CFS criteria. Limitations:: Checklist not validated prospectively; inter-rater reliability not assessed. Certainty:: 0.80/1.0 Research Stream:: schizophrenia-autoantibodies

15 Liu et al. 2025 — Clozapine + Rapamycin in Autoimmune Schizophrenia Model

Full Citation:: Liu D, Zhu C, Wei H. Clozapine and rapamycin reverse behavioral abnormalities in an animal model of autoimmune schizophrenia. Neuropharmacology. 2025;266:110286. DOI:: 10.1016/j.neuropharm.2024.110286 PMID:: 39733937 Published:: March 2025 Study Design:: Animal model (ApoE-/-; anti-SFT2D2 immunization) Sample Size:: Mouse groups Key Findings::

- Anti-SFT2D2 IgG caused behavioral deficits in ApoE-/- mice
- Both clozapine and rapamycin reversed: PPI deficits, motor impairment, cognitive impairment
- Both reduced microglial infiltration and restored dendritic spine density
- Synergy between antipsychotic and immunosuppressant mechanisms

Conclusion:: First demonstration in autoantibody-specific animal model that immunosuppressant + antipsychotic act synergistically. Limitations:: Animal model; ApoE-/- background; SFT2D2 is one of many potential targets. Certainty:: 0.55/1.0 Research Stream:: schizophrenia-autoantibodies

16 Krzystanek et al. 2026 — Immune Alterations in Treatment-Resistant Schizophrenia

Full Citation:: Krzystanek M, Bieś R, Bąk-Sosnowska M. Immune System Alterations in Treatment-Resistant Schizophrenia: A Systematic Review of the Current Evidence and Future Directions. International Journal of Molecular Sciences. 2026;27(9):3745. DOI:: 10.3390/ijms27093745 PMID:: 42123331 Published:: April 2026 Study Design:: Systematic review (PRISMA) Sample Size:: N/A Key Findings::

- TRS: elevated IL-6, IL-8, TNF-α, sCD25; CD33+/CD123+ cell expansion
- Autoantibodies (glutamatergic receptors) more prevalent in TRS
- Autoantibody levels decrease with clozapine treatment
- IgM-based predictive models for early identification
- Emerging immunomodulatory treatments: rituximab, levamisole, senolytics

Conclusion:: TRS has distinct immune profiles. Parallels severe ME/CFS subgroup. Limitations:: Dependent on included studies; many biomarkers not prospectively validated. Certainty:: 0.72/1.0 Research Stream:: schizophrenia-autoantibodies

17 Nemani et al. 2026 — REAP Phage Display in Schizophrenia (Preprint)

Full Citation:: Nemani K, Jaycox JR, Akcan U, et al. High prevalence of CNS-directed autoantibodies in patients with schizophrenia. bioRxiv [Preprint]. 2026 May 7. DOI: 10.64898/2026.05.04.722731. DOI:: 10.64898/2026.05.04.722731 PMID:: 42146360 Published:: May 2026 (preprint) Study Design:: Case-control with proteome-scale autoantibody profiling (REAP) Sample Size:: 352 schizophrenia, 971 community controls Key Findings::

- Striking elevation in extracellular autoantibody burden — ~2× control levels in most severely ill
- Present near disease onset; increases with age divergently from controls
- Targets CNS antigens: neuroactive receptors, ion channels, synaptic proteins, BBB antigens
- Anti-BBB autoantibodies impair barrier function ex vivo
- Higher baseline autoantibody burden → worse response to risperidone

Conclusion:: Humoral autoimmunity is pervasive in schizophrenia. REAP platform should be applied to ME/CFS. Limitations:: Preprint; Ring/yLab invention disclosure (Seranova Bio); cross-sectional; specificity of REAP not independently validated. Certainty:: 0.50/1.0 Research Stream:: schizophrenia-autoantibodies