Latest diagnosis and treatment for VGKC complex (LGI1 and Caspr2) antibodies associated diseases

Abstract

Voltage–gated potassium channels (VGKC) complex (LGI1 and Caspr2) antibodies associated encephalitis is less frequent than NMDAR encephalitis, but has a subacute course, with more prominent findings on head MRI and without remarkable cerebrospinal fluid findings.

Isaacs syndrome is mainly characterized by muscle cramps. Pain is also frequently associated with this syndrome. There are cases in which only pain and autonomic neuropathy precede, and a group of patients misdiagnosed with fibromyalgia.

The main mechanism of pain by Caspr2 antibody is that the antibody binds to Caspr2 on the surface of afferent neurons in dorsal root ganglion (DRG), resulting in suppression of the expression and function of VGKCs and causing neural hyperexcitability in the sensory system. Caspr2 has a key role in regulating cell–intrinsic DRG neuron excitability.