[Immune-Mediated Cerebellar Ataxias]

Abstract

Autoimmune mechanisms affect the cerebellum leading to the development of cerebellar ataxias (CAs), which are termed immune-mediated cerebellar ataxias (IMCAs). IMCAs have diverse etiologies. Gluten ataxia (GA), post-infectious cerebellitis (PIC), paraneoplastic cerebellar degeneration (PCD), opsoclonus myoclonus syndrome (OMS), anti-glutamate decarboxylase 65 antibody-associated CA (anti-GAD ataxia), and primary autoimmune cerebellar ataxia (PACA). In addition to these well-established entities, CAs are associated with autoimmunity against ion channels and their related proteins, synaptic adhesion proteins, transmitter receptors, glial cells, and brainstem antigens. Cell-mediated mechanisms are assumed to be involved in PCD, whereas accumulating evidence shows that anti-GAD antibodies decrease gamma-aminobutyric acid (GABA) release to elicit functional synaptic deficits. The therapeutic benefits of immunotherapies vary depending on the etiology. Early intervention is recommended when the cerebellar reserve, abilities for compensation and restoration of pathologies are preserved.