Myasthenia gravis (MG) and neuromyelitis optica (NMO) are autoimmune channelopathies of the peripheral neuromuscular junction (NMJ) and central nervous system (CNS) that are mainly mediated by humoral immunity against the acetylcholine receptor (AChR) and aquaporin-4 (AQP4), respectively. The diseases share some common features, including genetic predispositions, environmental factors, the breakdown of tolerance, the collaboration of T cells and B cells, imbalances in T helper 1 (Th1)/Th2/Th17/regulatory T cells, aberrant cytokine and antibody secretion, and complement system activation. However, some aspects of the immune mechanisms are unique. Both targets (AChR and AQP4) are expressed in the periphery and CNS, but MG mainly affects the NMJ in the periphery outside of CNS, whereas NMO preferentially involves the CNS. Inflammatory cells, including B cells and macrophages, often infiltrate the thymus but not the target-muscle in MG, whereas the infiltration of inflammatory cells, mainly polymorphonuclear leukocytes and macrophages, in NMO, is always observed in the target organ-the spinal cord. A review of the common and discrepant characteristics of these two autoimmune channelopathies may expand our understanding of the pathogenic mechanism of both disorders and assist in the development of proper treatments in the future.

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Immunopathogenesis in Myasthenia Gravis and Neuromyelitis Optica

Proportions of Th17 cells and Th17-related cytokines in neuromyelitis optica spectrum disorders patients: A meta-analysis.

Objective We investigated the contribution of several cytokines in the pathogenesis of first-onset neuromyelitis optica spectrum disorder (NMOSD) and determined the differences between aquaporin 4 immunoglobulin G (AQP4-IgG)-positive and AQP4-IgG-negative subtypes. Methods We enrolled 18 NMOSD (10 AQP4-IgG-positive and 8 AQP4-IgG-negative) and 8 multiple sclerosis (MS) patients, whose serum and cerebrospinal fluid (CSF) samples were collected during the acute phase of the first onset before immunotherapy. Fifteen patients with other noninflammatory neurological diseases (OND) were also included. The serum and CSF levels of interleukin (IL)-6, IL-10, IL-17, IL-21, IL-23, transforming growth factor (TGF)-β1 and the CSF levels of 3 biomarkers of axonal loss and astrocytic damage were measured using the human cytokine multiplex assay or ELISA. Results Serum levels of IL-10 and TGF-β1 and CSF levels of IL-6, IL-10, and TGF-β1 were significantly increased in first-onset NMOSD compared to in OND patients. In a subgroup analysis, the CSF levels of IL-6, neurofilament light protein (NFL), S100B, and glial fibrillary acidic protein (GFAP) were significantly more elevated in the AQP4-IgG-positive patients than in the AQP4-IgG-negative NMOSD patients. Correlations were found between the CSF cytokines and tissue damage biomarkers and the clinical findings in NMOSD patients. Notably, the CSF IL-6 level had the strongest correlation with the tissue damage biomarkers and it also correlated with CSF white blood cell (WBC) count. Conclusions IL-6 plays a role in the pathogenetic process of NMOSD, especially in the AQP4-IgG-positive subtype. Distinct pathogenesis exists between AQP4-IgG-positive and AQP4-IgG-negative NMOSD in the initial phase of the disease.

Cytokines and Tissue Damage Biomarkers in First-Onset Neuromyelitis Optica Spectrum Disorders: Significance of Interleukin-6

Structural and visual functional deficits in a rat model of neuromyelitis optica spectrum disorders related optic neuritis.

Background Alterations in the frequency or function of regulatory T cells (Tregs), which play a critical role in the maintenance of peripheral immune tolerance, are known to be involved in the pathogenesis of several autoimmune diseases. Neuromyelitis optica spectrum disorders (NMOSD) are autoimmune inflammatory diseases of the central nervous system (CNS), of which the etiology and mechanisms underlying its development are not completely understood. Although there is increasing evidence for the involvement of effector T cells in NMOSD, no data are available regarding the role of Tregs in its pathogenesis. Aim The aim of this study was to investigate the mRNA expression level of regulatory T cell genes in NMOSD. Methods We used gene expression array and RT-PCR analysis to study Treg cell genes in NMOSD Results A distinctive Treg gene signature in the peripheral blood of NMOSD patients is described, as well as significantly decreased FoxP3 mRNA expression in the peripheral blood mononuclear cells (PBMCs) of the patients vs that in the healthy controls (HCs) (NMOSD,1.8RQ vs HC, 6.8RQ, p = 0.01). Conclusions The present study shows downregulation at the mRNA expression level of a Treg key transcription factor FoxP3, in NMOSD. Exploration of Tregs function and interconnections in the peripheral immune system should advance our understanding of NMOSD pathogenesis.

Foxp3+ regulatory T cells expression in neuromyelitis optica spectrum disorders.

Objective: To screen cytokines and chemokines and determine their dynamic changes in the serum and cerebrospinal fluid (CSF) of patients with neuromyelitis optica spectrum disorder (NMOSD). Methods: Eight NMOSD with seropositive aquaporin-4 antibody (AQP4-IgG) were enrolled, as well as 8 matched patients with multiple sclerosis (MS) and 8 with noninflammatory neurological diseases, who were included as controls. In total, 102 cytokines and 34 chemokines were detected in the CSF and serum of NMOSD patients and controls. Results: CSF interleukin (IL)-17A levels were significantly higher in NMOSD patients in the relapsing phase (27.15 ± 11.33) than in those in the remitting phase (10.04 ± 3.11, p = 0.0017), and patients with MS (14.72 ± 3.20, p = 0.0283) and other controls (10.39 ± 11.38, p = 0.0021). CSF IL-6 levels were higher in the NMOSD patients in the relapsing phase (12.23 ± 3.47) than in those in the remitting phase (5.87 ± 2.78, p = 0.0001), and MS patients (7.38 ± 2.35, p = 0.0033) and other controls (7.50 ± 0.37, p = 0.0043). CSF CCL19 levels were also significantly higher in NMOSD patients in the relapsing phase (35.87 ± 27.07) than in those in the remitting phase (10.71 ± 3.62, p = 0.0215). Serum IL-19 levels were lower in NMOSD patients in the relapsing phase (6.23 ± 1.95) than in those in the remitting phase (10.72 ± 4.46, p = 0.0092). Further, there was a positive, significant correlation between serum IL-9 concentration and the Expanded Disability Status Scale score in the NMOSD patients in the relapsing phase ( p = 0.04). Conclusion: In addition to IL-6 and IL-17A, IL-16 and CCL19 act as proinflammatory cytokines/chemokines, while IL-19 plays a protective role in NMOSD pathogenesis.

Cytokine and Chemokine Profiles in Patients with Neuromyelitis Optica Spectrum Disorder.

Objectives To determine the differentiating features of autoimmune central nervous system (CNS) vasculitis and multiple sclerosis (MS) on susceptibility-weighted imaging (SWI). Methods Seventy-three patients (27 with autoimmune CNS vasculitis and 46 with MS) who underwent magnetic resonance imaging with SWI sequence were included. The features of lesions and distinct SWI findings were investigated in both diseases. Results On SWI, autoimmune CNS vasculitis presented with a higher prevalence of multiple microbleeds (48.1%), cortical superficial siderosis (70.4%), and tortuosity of the vascular route (59.3%) than were found in MS (p  Conclusions SWI may be a useful adjunct in distinguishing autoimmune CNS vasculitis from MS. The identification of multiple microbleeds and cortical superficial siderosis can point to a diagnosis of autoimmune CNS vasculitis.

Lei Wei

Papers

Cytokine and Chemokine Profiles in Patients with Neuromyelitis Optica Spectrum Disorder.

Susceptibility-weighted imaging in the differential diagnosis of autoimmune central nervous system vasculitis and multiple sclerosis.