A method for diagnosing a disease by detecting an autoantibody that binds to flotillin1 and/or flotillin2 in a sample, a polypeptide comprising flotillin1 and/or flotillin2 or a variant thereof, which may be immobilized, a method of treating a disease by applying to a subject the polypeptide that binds to an autoantibody, an autoantibody binding to flotillin1 and/or flotillin2, a method for isolating the autoantibody, a pharmaceutical composition, a medical device and test kit comprising the polypeptide, are provided. A method for detecting the presence of an autoantibody is also provided.
