Amyotrophic Lateral Sclerosis: Autoimmune Pathogenic Mechanisms, Clinical Features, and Therapeutic Perspectives

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the progressive death of motor neurons leading to fatal paralysis. The causes of ALS remain unknown; however, evidence supports the presence of autoimmune mechanisms contributing to pathogenesis. Although several environmental factors have been proposed, the only established risk factors are older age, male gender, and a family history of ALS. To date, there are no diagnostic test for ALS, and clinicians rely on the combination of upper motor neuron and lower motor neuron signs in the same body region. The aim of this paper was to provide a comprehensive review of current clinical literature with special focus on the role of autoimmunity in ALS, differential diagnosis, and available therapeutic approaches. Current evidence suggests a contribution of the innate immune system in ALS, with a role of microglial cell activation at the sites of neurodegeneration. The median time from symptom onset to diagnosis of ALS is 14 months, and this time estimate is mainly based on specific clinical signs and exclusion of ALS-like conditions. Several therapeutic approaches have been proposed, including immunosuppressive drugs, to reduce disease progression. Riluzole has been established as the only, although modestly effective, disease modifying therapy, extending mean patient survival by 3to 6 months. Recent advances in understanding the pathophysiology mechanisms of ALS encourage realistic hope for new treatment approaches. To date, the cornerstones of the management of patients with ALS are focused on symptom control, maintaining quality of life and improving survival.