Figure 2.

Clinical and serological features of patients with LGI1 and CASPR2 antibodies. (A) Daily frequency of faciobrachial dystonic seizures as recorded prospectively by the patient in figure 1 and the online video. Days 4–12 not recorded by patient (dotted line). His FBDS began with a frequency of 10 per day and rose to 200 per day, with a fall after corticosteroid initiation to around 150 per day. The remainder of his clinical progress is shown in figure 2A and suggests a marked improvement after PLEX. (B) Live LGI1 antibody cell based assay in the patient (from A) with FBDS and a healthy control (HC) showing human IgG deposition on the surface of HEK 293 T cells transfected with membrane-tethered EGFP-tagged LGI1 (LGI1-EGFP). (C) Levels of human IgG bound to surface-expressed LGI1-EGFP may also be quantified by flow cytometry. Five clouds of cells showing increasing IgG binding, left to right. (D) From patients with limbic encephalitis and autoimmune epilepsies, VGKC complex antibody determination misses some patients with LGI1 antibodies proven by flow cytometry. Both cut-offs determined as mean plus 3 SD. (E) CASPR2-IgG deposition in the sural nerve of a patient with peripheral nerve symptoms and CASPR2 antibodies who shows normal sural nerve morphology (F) by morphometric analysis in both large (8–12 µm) and small (<5 µm) nerve fibre density (G). This supports a neurophysiological disruption at the node with potential for reversibility. Thermal sweat test using alizarin red powder; face not tested, loss of sweat in yellow and sweating in blue with normalisation after immunotherapy (panel H compared with panel I. Panels (E–I) reproduced with permissions.⁸ CASPR2, contactin-associated protein 2; EGFP, enhanced green flourescent protein; FBDS, faciobrachial dystonic seizures; IVMP, 3 days of 1 g intravenous methylprednisolone; LGI1, leucine-rich glioma-inactivated 1; Pred, prednisolone; PLEX, plasma exchange; VGKC, voltage-gated potassium channel.