Background We conducted this study to describe detailed the clinical characteristics, ancillary test results and treatment response of a group of Chinese patients with anti‐IgLON5 disease. Methods We recruited 13 patients with positive IgLON5 antibodies in serum and/or cerebrospinal fluid from nine tertiary referral centers. Patients were enrolled from February 2017 to July 2021. We retrospectively collected information on the presenting and main symptoms, treatment response and follow‐up outcomes. Results The median age of onset for symptoms was 60 (range: 33–73) years and six of the 13 patients were females. The predominant clinical presentations included sleep disturbance (eight patients) and cognitive impairment (seven patients), followed by movement disorders (six patients). Parainfectious cause seemed plausible. Notably, we identified the first case of possible Epstein‐Barr virus (EBV)‐related anti‐IgLON5 disease. Coexisting neural autoantibodies were identified in two patients. Furthermore, two patients had other autoimmune diseases. The IgG subclass was determined in four patients, including two with dominant IgG4 subtype and two with dominant IgG1 subtype. Additionally, 10 patients were treated with immunotherapy and four patients exhibited improvement. Overall, six of 10 patients for whom follow‐up results were assessable had favorable clinical outcomes (modified Rankin Scale score ≤2). Conclusions The clinical spectrum of anti‐IgLON5 disease is variable. Our results highlight a boarder spectrum of anti‐IgLON5 disease.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease involving both upper and lower motor neurons, leading to paralysis and eventually death. Symptomatic treatments such as inhibition of salivation, alleviation of muscle cramps, and relief of spasticity and pain still play an important role in enhancing the quality of life. To date, riluzole and edaravone are the only two drugs approved by the Food and Drug Administration for the treatment of ALS in a few countries. While there is adequate consensus on the modest efficacy of riluzole, there are still open questions concerning the efficacy of edaravone in slowing the disease progression. Therefore, identification of novel therapeutic strategies is urgently needed. Impaired autophagic process plays a critical role in ALS pathogenesis. In this review, we focus on therapies modulating autophagy in the context of ALS. Furthermore, stem cell therapies, gene therapies, and newly-developed biomaterials have great potentials in alleviating neurodegeneration, which might halt the disease progression. In this review, we will summarize the current and prospective therapies for ALS.

Background Anti-IgLON5 disease is a rare neurological disorder associated with autoantibodies against the neuronal cell adhesion protein, IgLON5. Cellular investigations with human IgLON5 antibodies have suggested an antibody-mediated pathogenesis, but whether human IgLON5 autoantibodies can induce disease symptoms in mice is yet to be shown. Moreover, the effects of anti-IgLON5 autoantibodies on neurons and the precise molecular mechanisms in vivo remain controversial. Methods We investigated the effects of anti-IgLON5 antibodies in vivo and evaluated their long-term effects. We used two independent passive-transfer animal models and evaluated the effects of the antibodies on mouse behaviors at different time points from day 1 until day 30 after IgG infusion. A wide range of behaviors, including tests of locomotion, coordination, memory, anxiety, depression and social interactions were established. At termination, brain tissue was analyzed for human IgG, neuronal markers, glial markers, synaptic markers and RNA sequencing. Results These experiments showed that patient’s anti-IgLON5 antibodies induced progressive and irreversible behavioral deficits in vivo. Notably, cognitive abnormality was supported by impaired average gamma power in the CA1 during novel object recognition testing. Accompanying brain tissue studies showed progressive increase of brain-bound human antibodies in the hippocampus of anti-IgLON5 IgG-injected mice, which persisted 30 days after the injection of patient’s antibodies was stopped. Microglial and astrocyte density was increased in the hippocampus of anti-IgLON5 IgG-injected mice at Day 30. Whole-cell voltage clamp recordings proved that anti-IgLON5 antibodies affected synaptic homeostasis. Further western blot investigation of synaptic proteins revealed a reduction of presynaptic (synaptophysin) and post-synaptic (PSD95 and NMDAR1) expression in anti-IgLON5 IgG-injected mice. Conclusions Overall, our findings indicated an irreversible effect of anti-IgLON5 antibodies and supported the pathogenicity of these antibodies in vivo.