Screening for autoantibodies against the accompanying proteins of the LGI1 potassium channel is used in the investigation of patients with autoimmune encephalitis.
The LGI1 protein is a subunit in the potassium channel complex (VGKC) with a molecular weight of 60 kDa. Antibodies against LGI1 have been reported in classic autoimmune encephalitis and epilepsy. LGI1 antibodies are the second most common in autoimmune encephalitis after antibodies against the NMDA receptor. LGI1 antibodies are most commonly detected in men, with a diagnosis age between 30 and 80 years (mean 60 years). LGI-1 antibodies are associated with tumors (lung, thymoma, and other forms of tumors) in 25-31% of cases.
LGI1 belongs to the group of extracellular antigens. The titer of LGI1 antibodies can be used to monitor the efficacy of treatment.