A NOVEL DIAGNOSTICALLY RELEVANT AUTOANTIBODY

The present invention relates to a method for diagnosing a disease, preferably a disease associated with neurological symptoms, comprising the step detecting in a sample from a patient an autoantibody binding to ITPR1; a polypeptide comprising ITPR1 or a variant thereof, which is immobilized, preferably on a solid carrier; a use of a polypeptide comprising ITPR1 or a variant thereof for the diagnosis of a disease, preferably comprising the step detecting autoantibodies binding to ITPR1; a polypeptide comprising ITPR1 or a variant thereof, preferably immobilized, more preferably on a solid carrier, for use in the treatment of a disease; an autoantibody, preferably an isolated autoantibody, binding to a polypeptide comprising ITPR1, wherein the autoantibody is preferably in complex with said polypeptide; a method for isolating an autoantibody binding to ITPR1, comprising the steps contacting a sample comprising the autoantibody with a polypeptide comprising ITPR1 or a variant thereof under conditions compatible with formation of a complex, wherein said autoantibody binds to said polypeptide, isolating the complex formed in step a), dissociating the complex isolated in step b), and separating the autoantibody from the polypeptide; a pharmaceutical composition comprising a polypeptide comprising ITPR1 or a variant thereof; a medical or diagnostic device comprising a polypeptide comprising ITPR1 or a variant thereof; and a test kit for the diagnosis of a disease, comprising a polypeptide comprising ITPR1 or a variant thereof, wherein preferably the test kit comprises, in addition, a means for detecting the complex comprising an autoantibody binding to ITPR1