BackgroundAutoinflammatory disorders are distinguished by seemingly random episodes of systemic hyperinflammation, driven in particular by IL-1. Recent pre-clinical work has shown a key role for IL-1 in epilepsy in animal models, and therapies for autoinflammation including IL-1 blockade are proposed for refractory epilepsy.Case presentationHere, we report an adolescent female with signs of persistent systemic inflammation and epilepsy unresponsive to multiple anti-epileptic drugs (AED). She was diagnosed with generalized epilepsy with a normal brain MRI and an electroencephalogram (EEG) showing occasional generalized spike and slow wave discharges. Her diagnostic evaluation showed no signs of autoimmunity or genetic causes of epilepsy or periodic fever syndromes but persistently elevated serum inflammatory markers including S100 alarmin proteins. She experienced prompt clinical response to IL-1 blockade with first anakinra and then canakinumab, with near complete resolution of clinical seizures. Additionally, she displayed marked improvements in quality of life and social/academic functioning. Baseline gene expression studies on peripheral blood mononuclear cells (PBMC) from this patient showed significantly activated gene pathways suggesting systemic immune activation, including focal adhesion, platelet activation, and Rap1 signaling, which is an upstream regulator of IL-1β production by the NLRP3 inflammasome. It also showed activation of genes that characterize inflammasome-mediated autoinflammatory disorders and no signs of interferon activation. This gene expression signature was largely extinguished after anakinra treatment.ConclusionsTogether, these findings suggest that patients with epilepsy responsive to immune modulation may have distinct autoinflammatory features supporting IL-1 blockade. As such, IL-1 blockade may be highly efficacious adjunctive medication for certain refractory epilepsy syndromes.Electronic supplementary materialThe online version of this article (10.1186/s12974-018-1063-2) contains supplementary material, which is available to authorized users.

This is compelling preliminary data that suggests that corticosteroids may not be as effective compared to steroids followed by TPE. Given the importance of time-sensitive treatment, more formal studies may illuminate the ideal first-line treatment for anti-NMDA receptor antibody encephalitis.

nti-N-methyl-D-aspartate (NMDA) receptor antibodies are an increasingly recognized cause of encephalitis. Patients can present with encephalopathy, subacute behavioral changes, seizures, and occasionally a movement disorder. [1][2][3][4] Anti-NMDA receptor antibody encephalitis often occurs without clear provocation. Although tumors have been seen in approximately 50% of adult patients, they are much less common in pediatric patients. 3,5 Recently, anti-NMDA receptor IgG antibodies have been detected in up to 11% of a small series of patients with herpes simplex (HS) encephalitis, 6 and these authors also demonstrated IgA and IgM reactivity in their series. In that report, patients with previous HS encephalitis diagnosed by polymerase chain reaction (PCR) findings of HS virus (HSV) DNA in the cerebrospinal fluid (CSF) were found to have anti-NMDA receptor antibodies. In our report, we present an additional 2 cases with confirmed HS encephalitis who subsequently developed anti-NMDA receptor antibody encephalitis. Furthermore, an additional case series by Armangue et al 4 described a similar presentation in a 2-year-old girl. These time courses suggest a possible link between HSV-mediated neuronal damage and subsequent anti-NMDA receptor antibody-mediated disease, a theory also proposed by Prüss and colleagues. 6 If true, this theory might represent a need to shift treatment options for patients with encephalitis. IMPORTANCE Encephalitis mediated by anti-N-methyl-D-aspartate (NMDA) receptor antibodies and herpes simplex (HS) encephalitis are seemingly separate causes of encephalopathy in adults and children. Herpes simplex encephalitis is infectious, and anti-NMDA receptor antibody encephalitis is autoimmune in origin. Both can cause seizures and encephalopathy, although the latter can also cause psychiatric symptoms and movement disorders. Owing to the rarity of these 2 diseases, patients with co-occurrence are important because they alert clinicians to possible links between 2 seemingly separate processes.OBSERVATIONS In a case series of 2 patients observed at our center, we describe an infant and an adult who had confirmed HS encephalitis and then developed confirmed anti-NMDA receptor antibody encephalitis. Polymerase chain reaction testing for HS virus was performed. Testing for NMDA receptor antibodies was performed by Associated Regional and University Pathologists Laboratory in Salt Lake City, Utah. CONCLUSIONS AND RELEVANCEWe conclude that atypical cases of HS or other viral encephalitides should be investigated for concomitance of an autoimmune encephalitis. We suspect that the pathophysiologic mechanisms by which HS virus infects neurons produce a higher likelihood of contracting anti-NMDA receptor antibody encephalitis.