Effect of cyclosporine A on circulating immune complexes in IgA nephropathy

This work was undertaken to examine the effect of cyclosporine A (CyA) on the serum concentration of circulating immune complexes in 22 patients with IgA nephropathy during an infection-free period. They were randomly divided into 2 groups: 11 patients received oral cyclosporine A (5 mg/kg/day) for 12 weeks and 11 patients received placebo (0.05 ml/kg/day). A significant reduction of proteinuria was observed in patients on CyA therapy but not in those receiving placebo. IgG-circulating immune complexes (CIC) were determined by solid phase Clq enzyme immunoassay (Clq EIA) and radial immunodiffusion (RID) and IgA-CIC were determined by solid phase anti-C3 enzyme immunoassay (anti-C3 EIA) and radial immunodiffusion. There was no change in IgA-CIC measured by RID and anti-C3 EIA after 12 weeks of CyA therapy. Similarly, changes in IgG-CIC were not demonstrated with CyA therapy. No apparent decrease in IgG-CIC or IgA-CIC was observed with placebo treatment. Our study suggests that immunomodulation by CyA therapy does not affect the IgA-CIC and IgG-CIC levels in patients with IgA nephropathy.