Avidity of antibodies in SLE: relation to severity of renal involvement.

The avidity of antibodies to DNA in the sera of 8 patients with SLE was determined by saturation analysis and Scatchard plots. Five of the patients had severe lupus nephritis; the other 3 had relatively mild or no kidney disease. The Scatchard plots revealed components with high relative avidity in the patients with severe nephritis (K values 4.4-10.4 X 10(5) M-1 for nDNA), compared with the patients who had mild or no kidney disease (K values 0.3-1.8 X 10(5) M-1 for nDNA). Avidity measurements may be helpful in the evaluation and treatment of patients with SLE.