Antinuclear antibody-negative systemic lupus erythematosus. I. Anti-Ro(SSA) and anti-La(SSB) antibodies.

Anti-Ro(SSA) and anti-La(SSB) antibodies are found in approximately 25% of systemic lupus erythematosus patients. These antibodies are also detected in lupus patients who fail to demonstrate a significant antinuclear antibody (ANA) titer when mouse liver is employed as the substrate. Approximately 5% to 10% of systemic lupus patients are in this category. These ANA-negative, Ro(SSA)-positive lupus patients generally demonstrate a prominent widespread photosensitive dermatitis and are frequently initially seen and evaluated by a dermatologist.