The present invention relates to method for diagnosing a disease comprising the step detecting in a sample from a patient an autoantibody binding to flotillin1 and/or flotillin2, a polypeptide comprising flotillin1 and/or flotillin2 or a variant thereof, which is preferably immobilized, a use of said polypeptide for the diagnosis of a disease, an autoantibody binding to flotillin1 and/or flotillin2, a method for isolating said autoantibody, and a pharmaceutical composition, medical device or test kit comprising said polypeptide.
