Michael, Sophia

The long‐term clinical outcomes and associated prognostic factors in contactin‐associated protein‐like 2 (CASPR2)‐antibody diseases are unknown. A total of 75 participants with CASPR2 antibodies were longitudinally assessed for disability, quality‐of‐life, and chronic pain. Although most symptoms improved within 6 months of treatment, neuropathic pain and fatigue were the most immunotherapy refractory, and persisted for up to 6 years. Furthermore, these two factors—but not CASPR2 antibody levels or subclasses—independently predicted worse disability and quality‐of‐life at 24 months. Quality‐of‐life varied widely for any given modified Rankin Scale score, indicating a divergence between patient and clinician assessed outcomes. Further work should study the relative importance of these measures, and the immunopathogenesis underlying intractable symptoms. ANN NEUROL 2025;97:521–528

Abstract Objective Differentiating forms of autoimmune encephalitis (AE) from other causes of seizures helps expedite immunotherapies in AE patients and informs studies regarding their contrasting pathophysiology. We aimed to investigate whether and how Nuclear Magnetic Resonance (NMR)‐based metabolomics could differentiate AE from drug‐resistant epilepsy (DRE), and stratify AE subtypes. Methods This study recruited 238 patients: 162 with DRE and 76 AE, including 27 with contactin‐associated protein‐like 2 (CASPR2), 29 with leucine‐rich glioma inactivated 1 (LGI1) and 20 with N‐methyl‐ d ‐aspartate receptor (NMDAR) antibodies. Plasma samples across the groups were analyzed using NMR spectroscopy and compared with multivariate statistical techniques, such as orthogonal partial least squares discriminant analysis (OPLS‐DA). Results The OPLS‐DA model successfully distinguished AE from DRE patients with a high predictive accuracy of 87.0 ± 3.1% (87.9 ± 3.4% sensitivity and 86.3 ± 3.6% specificity). Further, pairwise OPLS‐DA models were able to stratify the three AE subtypes. Plasma metabolomic signatures of AE included decreased high‐density lipoprotein (HDL, −(C H 2 ) n −, –C H 3 ), phosphatidylcholine and albumin (lysyl moiety). AE subtype‐specific metabolomic signatures were also observed, with increased lactate in CASPR2, increased lactate, glucose, and decreased unsaturated fatty acids (UFA, –C H 2 CH=) in LGI1, and increased glycoprotein A (GlycA) in NMDAR‐antibody patients. Interpretation This study presents the first non‐antibody‐based biomarker for differentiating DRE, AE and AE subtypes. These metabolomics signatures underscore the potential relevance of lipid metabolism and glucose regulation in these neurological disorders, offering a promising adjunct to facilitate the diagnosis and therapeutics.

ImportanceRapid and accurate diagnosis of autoimmune encephalitis encourages prompt initiation of immunotherapy toward improved patient outcomes. However, clinical features alone may not sufficiently narrow the differential diagnosis, and awaiting autoantibody results can delay immunotherapy.ObjectiveTo identify simple magnetic resonance imaging (MRI) characteristics that accurately distinguish 2 common forms of autoimmune encephalitis, LGI1- and CASPR2-antibody encephalitis (LGI1/CASPR2-Ab-E), from 2 major differential diagnoses, viral encephalitis (VE) and Creutzfeldt-Jakob disease (CJD).Design, Setting, and ParticipantsThis cross-sectional study involved a retrospective, blinded analysis of the first available brain MRIs (taken 2000-2022) from 192 patients at Oxford University Hospitals in the UK and Mayo Clinic in the US. These patients had LGI1/CASPR2-Ab-E, VE, or CJD as evaluated by 2 neuroradiologists (discovery cohort; n = 87); findings were validated in an independent cohort by 3 neurologists (n = 105). Groups were statistically compared with contingency tables. Data were analyzed in 2023.Main Outcomes and MeasuresMRI findings including T2 or fluid-attenuated inversion recovery (FLAIR) hyperintensities, swelling or volume loss, presence of gadolinium contrast enhancement, and diffusion-weighted imaging changes. Correlations with clinical features.ResultsAmong 192 participants with MRIs reviewed, 71 were female (37%) and 121 were male (63%); the median age was 66 years (range, 19-92 years). By comparison with VE and CJD, in LGI1/CASPR2-Ab-E, T2 and/or FLAIR hyperintensities were less likely to extend outside the temporal lobe (3/42 patients [7%] vs 17/18 patients [94%] with VE; P < .001, and 3/4 patients [75%] with CJD; P = .005), less frequently exhibited swelling (12/55 [22%] with LGI1/CASPR2-Ab-E vs 13/22 [59%] with VE; P = .003), and showed no diffusion restriction (0 patients vs 16/22 [73%] with VE and 8/10 [80%] with CJD; both P < .001) and rare contrast enhancement (1/20 [5%] vs 7/17 [41%] with VE; P = .01). These findings were validated in an independent cohort and generated an area under the curve of 0.97, sensitivity of 90%, and specificity of 95% among cases with T2/FLAIR hyperintensity in the hippocampus and/or amygdala.Conclusions and RelevanceIn this study, T2 and/or FLAIR hyperintensities confined to the temporal lobes, without diffusion restriction or contrast enhancement, robustly distinguished LGI1/CASPR2-Ab-E from key differential diagnoses. These observations should assist clinical decision-making toward expediting immunotherapy. Their generalizability to other forms of autoimmune encephalitis and VE should be examined in future studies.

Abstract Patient‐reported quality‐of‐life (QoL) and carer impacts are not reported after leucine‐rich glioma‐inactivated 1‐antibody encephalitis (LGI1‐Ab‐E). From 60 patients, 85% (51 out of 60) showed one abnormal score across QoL assessments and 11 multimodal validated questionnaires. Compared to the premorbid state, QoL significantly deteriorated ( p < 0.001) and, at a median of 41 months, fatigue was its most important predictor ( p = 0.025). In total, 51% (26 out of 51) of carers reported significant burden. An abbreviated five‐item battery explained most variance in QoL. Wide‐ranging impacts post‐LGI1‐Ab‐E include decreased QoL and high caregiver strain. We identify a rapid method to capture QoL in routine clinic or clinical trial settings.

AbstractBackground and purposeDespite it being an immunotherapy‐responsive neurological syndrome, patients with autoimmune encephalitis (AE) frequently exhibit residual neurobehavioural features. Here, we report criminal behaviours as a serious and novel postencephalitic association.MethodsThis retrospective cohort study included 301 AE patients. Five of who committed crimes underwent direct assessments and records review alongside autoantibody studies.ResultsFive of 301 patients (1.7%) with AE exhibited criminal behaviours, which included viewing child pornography (n = 3), repeated shoplifting, and conspiracy to commit murder. All five were adult males, with LGI1 autoantibodies (n = 3), CASPR2 autoantibodies, or seronegative AE. None had evidence of premorbid antisocial personality traits or psychiatric disorders. Criminal behaviours began a median of 18 months (range = 15 months–12 years) after encephalitis onset. At the time of crimes, two patients were immunotherapy‐naïve, three had been administered late immunotherapies (at 5 weeks–4 months), many neurobehavioural features persisted, and new obsessive behaviours had appeared. However, cognition, seizure, and disability measures had improved, alongside reduced autoantibody levels.ConclusionsCriminal behaviours are a rare, novel, and stigmatizing residual neurobehavioural phenotype in AE, with significant social and legal implications. With caution towards overattribution, we suggest they occur as part of a postencephalitis limbic neurobehavioural syndrome.