PREVALENCE AND CLINICAL SIGNIFICANCE OF ANTIBODIES TO RIBONUCLEOPROTEINS IN SYSTEMIC LUPUS ERYTHEMATOSUS IN MALAYSIA

One hundred and seventy patients with systemic lupus erytbematosus(SLE) were studied for the prevalence of antibodies to the smallRNA-associated proteins Ro/SSA, La/SSB, Sm, UIRNP and Sm. Therelationship of these autoantibodies to different races, sexesand clinical manifestations of SLE was evaluated. Passive immunodiffusionwas employed using human spleen extract as antigen source forRo and rabbit thymus extract for La, Sm and UIRNP. We foundthe prevalence of antibodies to be as follows: anti-Ro/SSA,36%; anti-La/SSB, 8%; anti-Sm, 15%; anti-UIRNP, 21%. Exceptfor a low prevalence of anti-La, the prevalence of these antibodieswas similar to that in Western studies. The prevalence of anti-Ro/SSAis similar to that reported in the Western studies, but lowerthan that reported in other Oriental patients from Singaporeand Hong Kong. Linkages of anti-Ro with anti-La antibodies wereusual; however, although anti-Sm antibodies were usually associatedwith anti-UIRNP, they were more frequently associated with anti-Roantibodies. The Malay patients had a high prevalence of anti-UIRNPcompared to other races. No gender difference was detected.Anti-Sm antibody was associated with scrositis and anti-UIRNPantibodies with Raynaud's phenomenon. No association was foundbetween the presence of skin, renal or cerebral manifestationsand any specific antibodies or combination of antibodies. KEY WORDS: Systemic lupus erythematosus, Racial comparison, Ro/SSA, La/SSB, Sm, UIRNP