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This scientific commentary refers to 'Cerebrospinal fluid immunoglobulins in primary progressive multiple sclerosis are pathogenic' by Wong I et al. i (https://doi.org/10.1093/brain/awad031). CSF, CSF-IgG and recombinant IgG derived from B cells isolated from the CSF of patients with PPMS had variable pathogenic effects when injected into the C4-5 subarachnoid space of mice. The findings thus suggest the existence of a pathogenic IgG that is exclusive to PPMS-CSF and is, in this subset of patients, a major driver of multiple sclerosis pathology. [Extracted from the article]

OBJECTIVE: To define the diagnostic characteristics and predictors of treatment response in patients with suspected autoimmune dementia. PATIENTS AND METHODS: Between January 1, 2002, and January 1, 2009, 72 consecutive [...]

The antigen specificity of Anti‐Neuronal Nuclear Antibody‐type 3 (ANNA3)‐IgG is unknown. We identified Dachshund‐homolog 1 (DACH1) as the ANNA3 autoantigen and confirmed it by antigen‐specific assays, immunohistochemical colocalization and immune absorption experiments. Patients' median age was 63.5 years (range, 49–88); 67% were female. Neurological manifestations (information available for 30 patients) included one or more of neuropathy, 12; cognitive difficulties, 11; ataxia, 8; dysautonomia, 7. Evidence of a neoplasm was present in 27 of 30 (90%), most of neuroendocrine lineage. DACH1‐IgG is rare and represents a novel proposed biomarker of neurological autoimmunity and cancer. ANN NEUROL 2022;91:670–675 [ABSTRACT FROM AUTHOR]

Neuromyelitis optica is an autoimmune inflammatory disorder targeting aquaporin-4 water channels in CNS astrocytes. Histopathological descriptions of astrocytic lesions reported in neuromyelitis optica so far have emphasized a characteristic loss of aquaporin-4, with deposition of IgG and complement and lysis of astrocytes, but sublytic reactions have been underappreciated. We performed a multi-modality study of 23 neuromyelitis optica autopsy cases (clinically and/or pathologically confirmed; 337 tissue blocks). By evaluating astrocytic morphology, immunohistochemistry and AQP4 RNA transcripts, and their associations with demyelinating activity, we documented a spectrum of astrocytopathy in addition to complement deposition, microglial reaction, granulocyte infiltration and regenerating activity. Within advanced demyelinating lesions, and in periplaque areas, there was remarkable hypertrophic astrogliosis, more subtle than astrocytic lysis. A degenerative component was suggested by 'dystrophic' morphology, cytoplasmic vacuolation, Rosenthal fibres and associated stress protein markers. The abundance of AQP4 mRNA transcripts in sublytic reactive astrocytes devoid of aquaporin-4 protein supported in vivo restoration following IgG-induced aquaporin-4 endocytosis/degradation. Astrocytic alterations extending beyond demyelinating lesions speak to astrocytopathy being an early and primary event in the evolving neuromyelitis optica lesion. Focal astrocytopathy observed without aquaporin-4 loss or lytic complement component deposition verifies that astrocytic reactions in neuromyelitis optica are not solely dependent on IgG-mediated aquaporin-4 loss or lysis by complement or by IgG-dependent leucocyte mediators. We conclude that neuromyelitis optica reflects a global astrocytopathy, initiated by binding of IgG to aquaporin-4 and not simply definable by demyelination and astrocytic lysis. The spectrum of astrocytic morphological changes in neuromyelitis optica attests to the complexity of factors influencing the range of astrocytic physiological responses to a targeted attack by aquaporin-4-specific IgG. Sublytic astrocytic reactions are no doubt an important determinant of the lesion's evolution and potential for repair. Pharmacological manipulation of the astrocytic stress response may offer new avenues for therapeutic intervention. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To evaluate the prevalence and pathogenetic mechanisms of postural orthostatic tachycardia syndrome (POTS). PATIENTS AND METHODS: We reviewed the medical records of patients with POTS seen at the Mayo [...]

Objectives: To report the expanded neurological presentations and oncological associations of tripartite motif-containing protein 46 (TRIM46)-IgG seropositive patients.Methods: Archived sera/cerebrospinal fluid (CSF) were evaluated by tissue-based immunofluorescence assay to identify patients with identical axon initial segment (AIS)-specific staining pattern. Phage immunoprecipitation sequencing (PhIP-Seq) was used to identify the putative autoantigen.Results: IgG in serum (17) and/or CSF (16) from 25 patients yielded unique AIS-specific staining on murine central nervous system (CNS) tissue. An autoantibody specific for TRIM46 was identified by PhIP-Seq, and autoantigen specificity was confirmed by transfected COS7 cell-based assay. Clinical information was available for 22 TRIM46-IgG seropositive patients. Fifteen were female (68%). Median age was 67 years (range 25-87). Fifteen (68%) patients presented with subacute cerebellar syndrome (six isolated; nine with CNS accompaniments: encephalopathy (three), brainstem signs (two), myelopathy (two), parkinsonism (one)). Other phenotypes included limbic encephalitis (three), encephalopathy with/without seizures (two), myelopathy (two). Eighteen (82%) had cancer: neuroendocrine carcinomas (9; pancreatic (3), small-cell lung (4), oesophagus (1), endometrium (1)), adenocarcinomas (6; lung (2), ovarian (2), endometrial (1), breast (1)), sarcoma (2) and gastrointestinal tumour (1). Neurological symptoms in three followed immune checkpoint inhibitor (ICI) administration.Conclusions: This study supports TRIM46-IgG being a biomarker of paraneoplastic CNS disorders and expands the neurological phenotypes, oncological and ICI-related adverse event associations. [ABSTRACT FROM AUTHOR]