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A Simple Cell-based Immunofluorescence Assay to Detect Autoantibody Against the N-Methyl-D-Aspartate (NMDA) Receptor in Blood
Published on: January 9, 2018
Efgartigimod as a salvage therapy for anti-NMDAR encephalitis patients after first-line treatment failure: a case
Yanbo Zhang1,2,3, Zhijiao Song1,2,3, Lulu Zheng1,2,3
1Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
Background:
As an Fc receptor inhibitor, efgartigimod (EFG) could reduce serum IgG level, which might have a positive effect in the treatment of anti-N-methyl-D-aspartate-receptor (NMDAR) encephalitis (NMDARE). This study aimed to evaluate the treatment effects and safety of EFG on NMDARE patients following a first-line treatment failure.
Methods:
We retrospectively reviewed five NMDARE patients who failed in first-line treatment. All patients received intravenous EFG (10 mg/kg/week). We conducted neurological function evaluation, cerebrospinal fluid (CSF) and hematological examination, magnetic resonance imaging (MRI), and electroencephalogram (EEG) in all patients to evaluate the treatment effects of EFG.
Results:
After EFG treatment, the mean modified Rankin Scale (mRS) score decreased from 4.00 ± 0.70 at baseline to 1.60 ± 0.89, and the mean Clinical Assessment Scale in Autoimmune Encephalitis (CASE) score decreased from 14.6 ± 6.58 to 2.80 ± 2.95. The average period from EFG treatment to significant nerve function recovery (defined as mRS reduction ≥2) was 2.40 ± 2.19 weeks. Moreover, following a week after EFG treatment, the average serum IgG level decreased from 16.13 ± 7.47 g/L at baseline to 7.75 ± 5.17 g/L. Additionally, at 4 weeks post-EFG treatment, the IgG level decreased to 4.97 ± 2.30 g/L. Meanwhile, the anti-NMDAR antibody in CSF turned negative after EFG treatment in four out of five patients. The EFG helped in alleviating the abnormalities identified by MRI or EEG evaluations.
Conclusion:
The EFG can rapidly improve neurological function and enhance prognosis in NMDARE patients after first-line treatment failure. Meanwhile, no serious adverse effects were identified. The EFG treatment mechanism might be associated with the elimination of IgG, which contains anti-NMDAR antibodies.
