Ribosomal Autoantibodies

Abstract

This chapter focuses on the methods of detection and pathogenetic role of ribosomal autoantibodies and defines associations with disease or clinical presentation and characterizes antigenic and biological properties of these antibodies. Systemic lupus erythematosus (SLE) is also characterized in a significant subset of patients by autoantibodies to intracytoplasmic constituents. The most common antiribosomal autoantibodies are targeted against the phosphoproteins P0, P1, and P2 that are present in approximately 12-19% of SLE sera; reactivity of these anti-P antibodies is directed against a single common epitope present on the carboxyl terminus of each of these three proteins. Autoantibodies to ribosomes frequently target several protein or nucleic acid species within a single subcellular particle. The specificity of the response to particular molecular species of the complex demonstrates considerable commonality and overlap among patients with the same disease. Further, these protein nucleic acid targets are often essential functional components of the cell and the target within the particle is an essential functional or catalytic domain of the complex; for the antiribosomal response, the catalytic domain that is the principal target of the humoral autoimmune response is the “GTPase domain.”