Clinical features and outcomes of paediatric probable antibody-negative autoimmune encephalitis

Autoimmune encephalitis is a serious brain inflammation in which the immune system attacks the brain, leading to seizures, confusion, cognitive decline, and psychiatric symptoms. Although many autoimmune encephalitis-related antibodies have been discovered, some children with typical signs of autoimmune encephalitis test negative for known antibodies. These cases are referred to as antibody-negative autoimmune encephalitis (Ab-negative AE).

In this study, we reviewed the clinical features, treatments, and outcomes of 66 children diagnosed with probable Ab-negative AE at a major children's hospital in the Republic of Korea.

We found that: (1) Most children presented with altered mental status (92%) and seizures (85%). Nearly 90% received immunotherapy with high-dose steroids and/or intravenous immunoglobulin, and about one-third received additional treatments such as rituximab or tocilizumab. (2) Over 90% showed good functional recovery 1 year after treatment. (3) However, 44% continued to experience seizures, and around one-third had ongoing cognitive or behavioral problems after 1 year. (4) Children who had status epilepticus—a prolonged and severe seizure—at disease onset were more likely to have persistent seizures 1 year later.