A method for identifying molecules which mimic an idiotype of an autoimmune disease-associated auto-antibody (autoantibodies). The method comprises the following steps: (a) purifying autoantibodies from sera of one or more patients afflicted with the autoimmune disease； (b) binding the autoantibodies to a solid phase to form an affinity matrix； (c) contacting pooled plasma or B cells comprising immunoglobulins with the affinity matrix followed by removal of unbound plasma components； (d) eluting bound immunoglobulins, being anti-Idiotypic antibodies (anti-Id) to autoantibodies, from the matrix； (e) providing a molecular library comprising a plurality of molecule members； and (e) contacting the anti-Id with the molecular library and isolating those bound molecules which are bound by the anti-Id, the bound molecules being molecules which mimic an idiotype of autoantibodies. Also disclosed are such molecules.
