Systemic lupus erythematosus associated with antiribosomal P protein antibody.

Three patients with systemic lupus erythematosus had positive antiribosomal P protein antibodies. The patients are women who had mild diseases that did not involve prominent internal organs. By using an immunofluorescence method for the detection fo antinuclear antibodies that employs HEp-2 cells, these serum samples produced intense stainings on cytoplasm and nucleoli that were digested with RNase. With the use of an immunoblotting technique, these serum samples recognized three ribosomal P proteins, called PO (38 kd), P1 (19 kd), and P2 (17 kd). We suggest that antiribosomal P protein antibodies can be detected in patients with systemic lupus erythematosus and associated mild clinical features.