Immunotherapies for Anti-NMDA Receptor Encephalitis: Multicenter Retrospective Pediatric Cohort Study in China

Abstract BackgroundAnti-N-methyl-D-aspartate receptor (NMDAR) encephalitis has been discovered and termed more than a decade, but the establishment of standardized immunotherapy protocol for pediatric patients still needs more clinical evidence. To help move this forward, we investigated the current status of immunotherapies for pediatric anti-NMDAR encephalitis in 6 tertiary medical centers across China and evaluated how different immunotherapy strategies affected patient outcomes.MethodsA multicenter, retrospective study was conducted on pediatric patients diagnosed with anti-NMDAR encephalitis between November 2011 and December 2018. The clinical records including clinical manifestations, immunotherapy strategies, and outcomes were collected and analyzed. Treatment response and outcome were evaluated using mRS. Outcomes among the treatment groups were analyzed with the Chi-squared test or Fisher’s exact test. p < 0.05 was considered significant.ResultsA total of 386 patients were included in our study and the median onset age was 7.89 (range 0.5-18) years. All patients received first-line immunotherapy and the majority (341, 88.3%) used the standard combination of methylprednisolone pulses and intravenous immunoglobulins, but 211 patients did not show satisfactory improvement (mRS ≥ 3). Mainly three treatment strategies were applied after first-line immunotherapy: second-line immunotherapy, repetitive first-line immunotherapy, and maintaining oral prednisolone. For patients with mRS ≥ 4 after first-line immunotherapy, the incidence of poor outcome (mRS ≥ 3) in oral prednisolone group was higher than that in other treatment groups (0.025 < p < 0.05). No difference in complete recovery rate (mRS = 0) was found between patients receiving second-line and repetitive first-line immunotherapy, or patients using long-term and short-term prednisolone. The relapse rate of oral prednisolone group was higher than that of other treatment groups (p < 0.01), but the relapse rate of patients using long-term and short-term prednisolone had no statistical difference. ConclusionsFor patients with mRS ≥ 4 after first-line immunotherapy, second-line immunotherapy is recommended. When second-line immunotherapy is not applicable, repetitive first-line immunotherapy can be considered as an option. Both second-line and repetitive first-line immunotherapy are beneficial to reduce relapse rate. The duration of sequential oral prednisolone can be shortened after fully evaluating patients’ conditions.