The purpose of this study is to determine whether intravenous immunoglobulin (IVIG) treatment reduces significantly the number of epileptic seizures in cases of autoimmune epileptic seizures.

The purpose of this study is to determine if intravenous immunoglobulin (IVIG) treatment significantly reduces the number of epileptic seizures in cases of autoimmune epilepsy. Potential participants will be screened at an outpatient neurology clinic visit appointment. Interested qualified potential participants will be consented and offered participation in this trial. Once consent has been obtained, and it is determined that the participant meets all inclusion criteria, the participant will be randomized to either IVIG or placebo treatment for the next 5 weeks. Participants will return to Mayo Clinic for an evaluation. Those participants that received the placebo for 5 weeks will be given IVIG in an open label fashion for 5 weeks (week 7-11) then return to Mayo Clinic for evaluation. All participants will receive monthly phone calls after they complete the IVIG treatment for a period of 1 year from the end of IVIG 5 week course.

Inclusion Criteria:

• Seropositivity for Voltage Gated Potassium Channel Complex (VGKC) complex antibodies or positive for Leucine-Rich, Glioma Inactivated 1 (LGI1)/contactin-associated protein-like 2 (CASPR2) Antibody by cell based assay.
• And ≥ 2 seizures per week (mean of total over 1 week)
• And duration of epilepsy <3 years
• Male or female between the ages of 18 and 80 years of age
• Women and men of child bearing potential must agree to use a reliable form of contraception throughout the course of the study.
• Homecare treatment agency available at place of residence.

Exclusion Criteria:

• History of thrombotic episodes within the 2 years prior to enrollment

• Known allergic or other severe reactions to blood products including intolerability to previous IVIG

• Immunoglobulin A (IgA) deficiency

• Prior failed trial of high dose steroid (prednisone >60mg daily or methylprednisolone >1g weekly for >2 weeks)

• Reproductive status:

  • Women who are pregnant,
  • Women who are breastfeeding,
  • Women and men of childbearing potential who are unwilling or unable to use an acceptable method of birth control to avoid pregnancy for the entire study period, as evaluated by the investigator. (Women of non-childbearing potential are those that have a history of hysterectomy, bilateral oophorectomy, or are postmenopausal with no history of menstrual flow for > 12 months prior to screen visit.)

• Any surgical procedure (except for minor surgeries) within 4 weeks prior to baseline.

• Evidence of serious uncontrolled concomitant diseases that may preclude patient participation (physician determined), as described; Other nervous system disease, cardiovascular disease, hematologic/hematopoiesis disease, respiratory disease, muscular disease, endocrine disease, renal/urologic disease, digestive system disease, congenital or acquired severe immunodeficiency

• Known active infection (excluding fungal infections of nail beds or caries dentium) within 4 weeks prior to baseline.

• Evidence of chronic active hepatitis B or C.

• Active ischemic heart disease in the past year prior to baseline.

• Patients should not have severe renal or hepatic disease (determined by treating physician).

• Severe hypertension

The study period during which adverse events were collected is defined as the period from the initiation of any study procedures to the end of the study treatment follow-up, approximately 6 weeks.