case_images: PMC11771591_01
case_images: Schematic of the main clinical course and the electrophysiological parameters during the 532-day follow-up of our patient. The muscle motor assessments of the 4 limbs were evaluated by deriving the MRC scores (normal muscle force = 100). Disability was evaluated using the total overall neuropathy limitations scale (ONLS; maximum score = 12; 0, no disability; 12, total disability). In the electrophysiological context, we showed the evolution of the CMAP amplitude (an "axonal parameter") and the duration thereof (a "demyelinating" parameter) for the right median nerve (at wrist) compared to the normal values represented by the dotted red line. CMAP = compound muscle action potential, IVIg = intravenous immunoglobulin, mg = milligram, ms = millisecond, mV = millivolt, PLEX = plasma exchange.
case_images: medi-104-e41304-g001.jpg
case_images: PMC11771591_01_medi-104-e41304-g001.jpg
case_images: F1
case_images: He was admitted to the medical intensive care unit wherein he developed facial diplegia and complete ophthalmoplegia in addition to requiring mechanical ventilation and gastrostomy (Fig. 1; D15: GBS-DS score of 5/6). An electrophysiological study revealed clear improvement but the CMAP remained low, subsequently attributed to signs of mild demyelination in all 4 limbs (Fig. 1; Table 1).
case_images: Sera (diluted 1:100) obtained before and after treatment were incubated with cells transfected to allow NF155 and NF186 expression (A) or beads with recombinant NF155 (B). After washing, cells and beads were incubated with anti-IgG (A), anti-IgG1, anti-IgG2, anti-IgG3, or anti-IgG4 fluorescence-labeled antiserum (B). The fluorescence levels were compared to those obtained using non-transfected cells or control beads. We observed a positive result for anti-NF155 and anti-NF186 antibodies at D114, with negativity at D532 (A); these were only anti-IgG4 antibodies (B). AF-488 = Alexa FluorTM 642 (it specifically detects IgG1 antibodies), AF-642 = Alexa FluorTM 642 (it specifically detects IgG2 antibodies), AF-750 = Alexa FluorTM 750 (it specifically detects IgG3 antibodies), NF = neurofascin, PB = plasmablasts (circulating plasmablasts are elevated in active IgG4 related diseases, so it is used as a biomarker of IgG4 antibodies).
case_images: medi-104-e41304-g002.jpg
case_images: PMC11771591_01_medi-104-e41304-g002.jpg
case_images: F2
case_images: Flow cytometry clearly showed IgG4 anti-pan-neurofascin positivity in human embryonic kidney cells transfected with NF155 and NF186 plasmids and on bead coated with NF155 proteins (Fig. 2). Finally, on D377, his anti-pan-neurofascin autoantibody status became negative and remained negative on D532 (Fig. 2).