Clinical significance of antinuclear antibodies in systemic lupus erythematosus.

Sera from 70 patients with systemic lupus erythematosus were studied for antinuclear antibodies and its clinical significance. Indirect immunofluorescence technique with mouse liver tissue and Crithidia luciliae flagella as substrates was used to detect antinuclear antibodies (FANA) and antibodies to double-stranded DNA (anti-ds DNA), respectively. Double immunodiffusion method identical with reference sera was used to detect antibodies to extractable nuclear antigens (anti-ENA). The prevalence of fluorescence antinuclear antibodies, antibodies to ds DNA and antibodies to ENA were 95.7%, 52.9% and 58.6%, respectively. Patients with homogeneous pattern of FANA presented clinically with high incidence of LE cell phenomenon. Patients with anti-ds DNA antibodies presented clinically with high incidences of serositis, profuse proteinuria, low serum C3 and high clinical activity. Patients with anti-RNP antibodies presented with high incidence of Raynaud's phenomenon and low incidence of anti-ds DNA antibodies. Patients with severe renal involvement showed a good correlation with high titer of anti-ds DNA antibodies and low serum C3. Therefore, these two factors together are helpful to predict the severity of renal involvement at the time of serum sample was obtained.