Central nervous system antibody-mediated diseases with autonomic involvement – Focus on VGKC-complex (LGI1, CASPR2), NMDAR and GlyR antibodies

Antibodies to receptors and ion channels are no known to cause neurological diseases of the periphery (eg myasthenia gravis) and the central nervous system (eg. Limbic encephalitis). In addition, there are now a number of different antibodies that often affect the autonomic nervous system (several that will be addressed by other speakers here). Antibodies to voltage-gated calcium channels (VGCC) in Lambert Eaton myasthenic syndrome cause weakness distinguished from myasthenia by dry mouth, constipation and bladder problem; antibodies to components of the voltage-gated potassium channel complex (VGKC-complex) cause fasciculations, muscle cramps and pain, often associated with excessive sweating, constipation or other gastro-intestinal disturbance. These VGKC-complex antibodies, principally binding to CASPR2, also associate with the CNS condition Morvan’s syndrome in which the autonomic disturbance can be more severe and cardiac arrhythmia common. Antibodies that exclusively act in the CNS can also cause autonomic instability as in NMDAR-antibody encephalitis, respiratory and bladder disturbance in progressive encephalomyelitis with rigidity and myoclonus with glycine receptor antibodies, and sometimes cardiac disturbance in patients with LGI1 antibodies that bind the other main VGKC-complex protein. Thus the autonomic system can be affected by autoantibodies acting centrally as well as peripherally, and the autonomic effects of these diseases need to be studied in more detail. In each case, the disease responds to immunotherapies such as steroids, plasma exchange, intravenous immunoglobulins and more aggressive immunosuppressive treatments. Thus these are all potentially reversible neurological disorders.