Antibodies directed against ribosomal protein determinants in the sera of patients with connective tissue diseases.

A collection of sera from patients with systemic lupus erythematosus, rheumatoid arthritis, mixed connective tissue disease, Sjögren's syndrome, progressive systemic sclerosis, and the reflex sympathetic dystrophy syndrome was screened for the presence of antibodies recognizing determinants on the protein moiety of human ribosomes after electrophoretic separation in polyacrylamide and blotting on nitrocellulose. In addition to the antibodies already described against the RNA moiety or against the whole ribosome, some autoimmune sera contain antibodies against the protein moiety. The results obtained by this methodology were compared with those obtained by a microtiter procedure.