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Background: Retinal atrophy in the chronic phase of optic neuritis (ON) in anti-aquaporin-4 antibody (AQP4-Ab)-positive neuromyelitis optica spectrum disorder (NMOSD) and anti-myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) remains unclear., Methods: Patients with these diseases were repeatedly evaluated using optical coherence tomography (OCT) for the circumpapillary retinal nerve fiber layer (cpRNFL) and macular ganglion cell complex (mGCC) in the ON-involved eyes during relapse-free period after the first ON episode before relapse. Optic MRI with short tau inversion recovery (STIR) sequences was further evaluated retrospectively., Results: Twelve patients with MOGAD (20 eyes with ON-involvement) and 14 with AQP4-Ab-positive NMOSD (16 eyes with ON-involvement) were enrolled. The progression of retinal atrophy ≥12 months after onset was observed in AQP4-Ab-positive NMOSD, but was not apparent in MOGAD. A decrease in retinal thickness by the same amount results in more severe visual impairment in AQP4-Ab-positive NMOSD. On optic MRI, the residual STIR hyperintensity in the optic nerves remained in the chronic phase in almost all eyes with ON in both diseases. Optic nerve atrophy occurred in all evaluated ON-involved eyes in AQP4-Ab-positive NMOSD, while it was observed in half of ON-involved eyes in MOGAD., Conclusions: Progression of retinal atrophy in the chronic phase has been observed in patients with AQP4-Ab-positive NMOSD, while it remains uncertain in patients with MOGAD. The visual impairments upon similar levels of retinal atrophy would be worse in AQP4-Ab-positive NMOSD, possibly attributable in part to a higher incidence of optic nerve atrophy in this disease., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Hashimoto's encephalopathy (HE) is thought to be caused by disorders of immune mechanisms. Although immunologically mediated central nervous system vasculitis or unidentified anti-neuronal autoantibodies have been suspected of causing HE, its pathogenesis is still unclear. For the study presented here, two patients with typical clinical and laboratory/electrophysiological findings of HE were analyzed to clarify the role of anti-neuronal autoantibodies in the pathogenesis of HE. The autopsied brain of one of the patients was histopathologically examined. For Western blotting analysis and immunohistochemistry, serum and purified immunoglobulin G obtained from the other patient were used. Autopsy revealed no evidence of central nervous system vasculitis or other abnormal findings in the brain. The patient's serum contained an anti-neuronal autoantibody that immunohistochemically labeled neurons of mouse and human cerebral cortices and reacted with the 36-kDa antigenic protein present in a soluble fraction obtained from human cerebral cortex. Our results indicate that anti-neuronal autoantibodies may be associated with the pathogenesis of HE.

Aceruloplasminemia is characterized by excessive neurovisceral accumulation of iron due to mutations in the ceruloplasmin gene. We report that the levels of malonaldehyde (MDA) and 4-hydroxynonenals (4-HNE) were elevated both in the frontal cortex and putamen in two patients with aceruloplasminemia compared with those in controls. Immunohistochemical analysis with an antibody raised against HNE-modified protein showed a large number of immunoreactive neurons and glias in the brain of a patient. MDA and 4-HNE are good indicators of lipid peroxidation because they are generated in the process of oxidation of polyunsaturated fatty acids. The data strongly suggest that the increase of oxygen free radicals associated with excessive iron accumulation plays an important pathogenic role in the process of neuronal cell death in the brains of patients with aceruloplasminemia.

Adoptive transfer of experimental allergic encephalomyelitis (EAE) was achieved in Lewis rats using spleen cells incubated in vitro with various lectins. When stimulated with concanavalin A (Con A), its derivative succinyl-Con A, Lens culinaris or Pisum sativum agglutinin, spleen cells obtained from rats immunized with encephalitogenic emulsion could transfer EAE to normal syngeneic recipients. In contrast, spleen cells stimulated with Phaseolus vulgaris, Robinia pseudoacacia or Wisteria floribunda agglutinin did not transfer EAE. Transfer of EAE with Con A-activated spleen cells was abolished by the specific hapten inhibitor, alpha-methyl-D-mannoside, but not by D-glucose. Our data indicate that the in vitro responses to lectins may differ among T cell subpopulations. Lectins may prove useful for investigating the nature of EAE-effector cells and the mechanisms of immune regulation in this autoimmune central nervous system disease.

Experimental allergic encephalomyelitis (EAE) can be transferred by spleen cells stimulated in vitro with D-mannose-binding lectins but not with N-acetyl-D-galactosamine (GalNAc)-binding lectins. EAE could also be passively transferred by spleen cells following incubation with wheat germ agglutinin (WGA), in which case the disease transfer was abolished by the specific hapten inhibitor, N-acetyl-D-glucosamine. In the presence of rat T cell monoclonal antibody, either W3/25 or OX-8, both concanavalin A and Wisteria floribunda agglutinin stimulated helper and suppressor T subpopulations. On the other hand, GalNAc-binding lectins were less effective than D-mannose-binding lectins in generating interleukin 2 (IL2) in the culture supernatant, whereas WGA-stimulated spleen cells did not produce IL2. Furthermore, spleen cells cultured with pure IL2 could not transfer EAE to the recipients. These data suggest that some factors distinct from IL2 are required for the differentiation of EAE-effector precursors into the final effector cells in this transfer system.

Experimental allergic encephalomyelitis (EAE) in Lewis rats is an acute, monophasic autoimmune disease, and rats recovering from EAE are generally resistant to active reinduction. However, following immunosuppression with a high dose (100-200 mg/kg) of cyclophosphamide (CY), EAE was reinduced in convalescent rats, irrespective of whether or not they were rechallenged with the encephalitogenic inoculum. Reinduction of EAE was not observed in rats treated with low doses (20 mg/kg or less) of CY. A selective inhibition of suppressor cells during the convalescent stage may be responsible for the reinduction of EAE in Lewis rats.