Antibodies to Ro and La.

Precipitating antibodies to Ro and La occur in a subset of patients with systemic lupus erythematosus (SLE) constituting just under 50 and 20% respectively of the total spectrum. These precipitating autoantibodies are even more prevalent in primary Sjögren's syndrome (SS) occurring in 60-80% (anti-Ro) and 40-60% (anti-La) of that disease. Patients with an overlap of SLE and SS virtually all possess both anti-Ro and anti-La. These autoantibodies appear years before the appearance of clinical disease as evidenced by the behavior of women who possess them and herald this presence by having children born with the manifestations of neonatal lupus, principally a characteristic lupus dermatitis or complete congenital heart block. The close association of several clinical manifestations involving the skin, lung, and blood elements suggests a pathogenic role for these autoantibodies in disease expression. The elucidation of these relationships should greatly improve our understanding of the etiopathogenesis of both SLE and SS.