The use of anti-ribosomal P antibodies in the diagnosis of cerebral lupus�superiority of western blotting over enzyme-linked immunosorbent assay

EYT Chan, OKH Ko, JWM Lawton, CS Lau
Department of Pathology, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong

This study investigated the use of anti-ribosomal P antibodies in the diagnosis of cerebral complications of systemic lupus erythematosus using two different methods�western blotting and enzyme-linked immunosorbent assay. Anti-ribosomal P antibodies in patient serum were detected in both methods using a purified ribosomal P antigen substrate. Western blotting detected anti-ribosomal P antibodies with a 90% specificity for systemic lupus erythematosus in 56% of patients with the disease. The detection of anti-ribosomal P antibodies by western blotting in patients with systemic lupus erythematosus was significantly associated with psychosis and/or seizures; detection was positive in 90% of patients with these cerebral complications and in 41% of those without. Elevation of the level of anti-ribosomal P antibody, as measured by enzyme-linked immunosorbent assay, was 99% specific for systemic lupus erythematosus in 44% of patients with systemic lupus erythematosus that was not associated with cerebral involvement. We conclude that the measurement of anti-ribosomal P antibodies by western blotting is helpful in the diagnosis of cerebral lupus in selected patients.

Hong Kong Med J 1998;4:145-50

Key words: Autoantibodies/analysis; Blotting, western; Enzyme-linked immunosorbent assay; Lupus erythematosus, systemic/immunology; Ribosomal proteins/immunology