Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Acquired neuromyotonia (ANM) is associated with antibodies to voltage‐gated K<jats:sup>+</jats:sup> channels (VGKCs). ANM sera reduce the number of K<jats:sup>+</jats:sup> currents in neuronal cell lines, but it is not clear how the antibodies act. Here, we show by using the NB‐1 cell line that the reduction in K<jats:sup>+</jats:sup> currents by IgG is independent of added complement. IgG Fc and Fab fragments from ANM sera had no effect, but three of four ANM F(ab′)<jats:sub>2</jats:sub> fragments significantly reduced K<jats:sup>+</jats:sup> currents. Thus, cross‐linking of the channels by divalent antibodies is likely to be an important mechanism in reducing K<jats:sup>+</jats:sup> currents. Ann Neurol 2004;56:440–444</jats:p>