In the last years, different kinds of
limbic encephalitis associated with
autoantibodies against
ion channels and
synaptic receptors have been described. Many studies have demonstrated that such
autoantibodies induce channel or receptor dysfunction. The same mechanism is discussed in immune-mediated
cerebellar ataxias (IMCAs), but the pathogenesis has been less investigated. The aim of the present review is to evaluate what kind of cerebellar
ion channels, their related
proteins, and the synaptic machinery
proteins that are preferably impaired by
autoantibodies so as to develop
cerebellar ataxias (CAs). The cerebellum predictively coordinates motor and cognitive functions through a continuous update of an internal model. These controls are relayed by cerebellum-specific functions such as precise neuronal discharges with
potassium channels, synaptic plasticity through calcium signaling pathways coupled with voltage-gated
calcium channels (VGCC) and
metabotropic glutamate receptors 1 (
mGluR1), a synaptic organization with
glutamate receptor delta (GluRĪ“), and output signal formation through chained GABAergic neurons. Consistently, the association of CAs with anti-
potassium channel-related
proteins, anti-VGCC, anti-mGluR1, and GluRĪ“, and anti-
glutamate decarboxylase 65
antibodies is observed in IMCAs. Despite ample distributions of
AMPA and
GABA receptors, however, CAs are rare in conditions with
autoantibodies against these receptors. Notably, when the
autoantibodies impair synaptic transmission, the autoimmune targets are commonly classified into three categories: release machinery
proteins, synaptic adhesion molecules, and receptors. This physiopathological categorization impacts on both our understanding of the pathophysiology and clinical prognosis.