Effectiveness of immunotherapy in a CASPR2 and LGI1 antibody-positive elderly patient with Isaacs’ syndrome: a case study

Isaacs’ syndrome (IS) is an acquired autoimmune disorder which causes peripheral nerve hyperexcitability, characterized by spontaneous muscle twitching, stiffness, and cramping of muscle extremities. It is regarded as a voltage-gated potassium channel (VGKC) antibody-mediated autoimmune disease [1]. VGKC is mainly responsible for regulating current across nerve cell membranes, which consequently influences the generation of neuronal action potentials [2]. VGKC comprises of various protein components, among which antibodies against contactin-associated protein-like 2 (CASPR2) and leucine-rich glioma-inactivated 1 (LGI1) are associated with IS [1]. While anti-epileptics usually relieves symptoms in IS patients, it is ineffective or only partially effective in VGKC antibody-positive IS patients. Immune therapy has been shown to be an effective treatment strategy in CASPR2 antibody-positive IS. Here, we describe the effectiveness of immune therapy in a CASPRS2 and LGI1 antibody-positive IS patient. …