Sera of patients with systemic autoimmune diseases frequently contain autoantibodies to nuclear autoantigens. Immunoblotting of recombinant and native autoantigens is a commonly used technique for the identification and characterization of autoantibody specificities. Here we describe an easy procedure which facilitates the comparison of antibody specificities by reusing the same immunoblot for at least three times in order to detect an abundantly expressed autoantigen in total cellular extracts.