Reactivity of anti-NMDA receptor antibodies in the CSF of a patient with anti-NMDA receptor encephalitis

Section of rat hippocampus immunostained with the CSF of a patient with anti-NMDA receptor encephalitis (A); boxed area shown in detail in (B). Immunostaining of live dissociated fetal rat hippocampal neurons demonstrates intense reactivity with the receptor on the cell surface (C). In comparison, the reactivity of anti-Hu antibodies in the CSF of a patient with paraneoplastic encephalomyelitis is shown in (D) and detailed in (E). These antibodies target an intracellular neuronal protein and do not show reactivity with live neurons because they cannot reach their intracellular target (F). Scale bars: A, B = 500 mm; C, D = 20 mm; E, F = 10 mm. Reproduced with permission from Dalmau J. NMDA receptor encephalitis and other antibody-mediated disorders of the synapse: The 2016 Cotzias Lecture. Neurology 2016;87(23):2471-82.