Cerebrospinal fluid indices as predictors of treatment response in autoimmune encephalitis.

BACKGROUND: Cerebrospinal fluid (CSF) indices reflecting intrathecal antibody production and blood-brain barrier impairment are not routinely assessed in patients with autoimmune encephalitis (AE). We aimed to study CSF indices and their association with the prognosis of AE. METHODS: This retrospective cohort study conducted at Amrita Institute of Medical Sciences (AIMS), Kochi, India, included 60 patients aged more than 18 years with definite/probable/possible AE admitted to the Department of Neurology from August 2016 to November 2021. We introduced a classification of treatment response based on modified Rankin Scale change over time and treatment modalities. RESULTS: In our cohort of 60 patients (six [10%] seropositive cases), a good rapid treatment response was associated with CSF white blood cell count of more than 4 cells/mm3 (OR, 4.57; 95% CI 1.31-15.96; P = .02) and positive immunoglobulin G (IgG) Local Synthesis (OR, 7.27; 95% CI 1.56-33.86; P = .01). Albumin Index had association with a poor Glasgow Coma Scale score at the nadir of the disease (OR, 1.17; 95% CI 1.01-1.34; P = .04). Similar results were yielded in the seronegative cohort. IgG Local Synthesis appeared to be a strong predictor for good rapid treatment response in both univariate and multivariate (adjusted OR, 28.71; 95% CI 2.12-389.22; P= .01) analysis. Time to immunotherapy was reversely correlated with good response overall (in the cohort with outliers removed [N = 49]: unadjusted OR 0.97, 95% CI 0.95-0.99; P= .01; adjusted OR 0.97; 95% CI 0.95-0.99; P= .008). CONCLUSION: CSF indices reflecting intrathecal antibody production and blood-brain barrier impairment appear to be promising predictors of disease severity and therapeutic response in patients with autoimmune encephalitis.

The prevalence and clinical phenotype of dual seropositive neuromyelitis optica spectrum disorders at a national reference center in South Asia.

BACKGROUND: Neuromyelitis Optica Spectrum Disorders (NMOSD) is an autoimmune syndrome that is frequently positive for Aquaporin 4 (AQP4) IgG or Myelin Oligodendrocyte Glycoproteins (MOG) IgG. However, dual positivity to both is rare. OBJECTIVE: To assess the prevalence of dual-positive NMOSD and outline its clinical phenotype. DESIGN/METHODS: This is a retrospective cross-sectional study conducted at a tertiary healthcare center in South Asia between August 2018 and November 2021. The serum and/or CSF samples of suspected cases of NMOSD were tested for both AQP4-IgG and MOG-IgG using an Indirect immunofluorescence test on transfected cells. RESULTS: During the study period, 1935 cases of NMOSD were tested for both antibodies- 65 patients (3.35%; 57 females and 8 males) tested positive for AQP4-IgG, 217 patients (11.21%; 122 females and 95 males) tested positive for MOG-IgG and 3 patients (0.15%; 2 females and 1 male) showed dual positivity. There was a strong female preponderance in all three groups (87.69%, 56.22%, and 66.66% respectively). This study identified 3 patients with dual positivity. The first patient (42 years, Male) presented with area postrema syndrome initially and subsequently relapsed by developing right-sided numbness of the temporal area and limbs during which he tested dual positive. The second patient (27 years, Female) presented with bilateral optic neuritis (left>right) initially and subsequently relapsed following an episode of a seizure with left-sided hemiplegia. The third patient (25 years, Female) initially presented with acute bilateral optic neuritis and later developed left-sided hemiplegia post-recovery at which point she tested dual positive. Management using methylprednisolone was ineffective for all three patients, however, plasmapheresis and/or periodic rituximab injections produced an excellent response. CONCLUSIONS: Our study reports that the prevalence of dual-positive NMOSD is 0.15% and its clinical phenotype is more similar to NMO rather than MOG- associated disease.

Autoimmune parkinsonism with faciobrachiocrural dystonic seizures: a new phenotype of leucine-rich glioma-inactivated 1 (LGI1) autoimmunity.

Extrapyramidal symptoms are seen in patients with leucine-rich glioma-inactivated 1 (LGI1) antibody-positive patients infrequently and this can be successfully treated with immunotherapy. This is a retrospective hospital-based study from 2013 to 2021 at a tertiary care referral hospital in South India. LGI1 antibody-positive cases with Faciobrachio-crural dystonic seizures [FBCDS] were identified by reviewing electronic medical records and Neuroimmunology laboratory register. Clinical and laboratory details and treatment outcomes were analysed. There was a total of 23 patients who were positive for LGI1 antibody. Of these, three cases had FBCDS (2 males, age range 30-76 years). Upon reviewing the records they had additional asymmetric parkinsonian features. All had similar presentations with progressive slowness of activities and gait and later went on to have paroxysmal events of sudden falls with vocalization. Prolonged VEEG monitoring captured the habitual event, which were confirmed to be FBCDS. MRI did not show significant structural abnormalities, CSF showed elevated proteins and normal cell in two and lymphocytic pleocytosis in one, PET scans ruled out malignancy. Of the three patients, two were completely relieved of FBCDS with immunosuppression and there was complete resolution of extrapyramidal features in all. Thus, the patients in our series of FBCDS showed additional features of parkinsonism which responded well to immunotherapy. Involvement of basal ganglia can explain all the manifestations of this phenotype. This series reveals a unique phenotype of the LGI1 antibody.