The purpose of this study is to evaluate the safety and efficacy of IGIV 10% in patients with autoimmune encephalitis

Inclusion Criteria:

1. Male or female, aged more than 12 years.(adolescent or adult)

2. Subject who all three of the following diagnosis criteria for possible autoimmune encephalitis have been met.

   • Subacute onset (rapid progression of less than 3 months) of working memory deficits(short-term memory loss), altered mental status, or psychiatric symptoms.

   • At least one of the following:

     • New focal CNS findings
     • Seizure not explained by a previously known seizure disorder
     • CSF pleocytosis (WBC count ≥ 5/mm2)
     • MRI features suggestive of encephalitis

   • Reasonable exclusion of alternative causes

3. Subjects or parent/legal representative willing to provide written informed consent

Exclusion Criteria:

1. Subject who has received Immunoglobulin therapy within 10 weeks prior to screening
2. Subject who has a history of hypersensitivity or shock to ingredient of immunoglobulin
3. Subject who has been diagnosed with IgA deficiency
4. Subject who has renal disorder (creatinine clearance < 10 ml/min) or requires dialysis
5. Subject who has been diagnosed with hemolytic anemia or anemia from blood loss
6. Subject who has been diagnosed with immuonological competence or immunodeficiency
7. Subject who has high risk of thrombus or embolism (History of thrombus/embolism or cerebro/cardiovascular disorder within 3 months prior to screening)
8. Subject who has low heart condition (Congestive heart failure >NYHA functional class Ⅱ: unstable coronary artery disease or myocardiac infarction within 3 months prior to screening)
9. Subject who cannot prohibit the previously administrated steroids by investigator's discretion (ex. Suspicion of steroid dependence, hypoadrenocorticism, when treatment effects are expected, etc.)
10. Females who are pregnant or breast feeding
11. Subject who is considered by investigator to ineligible for the study.