Oxidized immunoglobulin G in patients with end-stage renal disease treated by hemodialysis

Patients with end-stage renal disease treated by hemodialysis have enhanced oxidative stress that may result in oxidation of IgG and resultant functional changes. In this study, Western blot analysis was used to assess the oxidized protein content of IgG samples purified from plasma of 8 controls and 11 patients on hemodialysis. In certain experiments, oxidized IgG was digested with papain and Western blot analysis was performed to identify oxidized Fc fragments. Compared to plasma IgG from controls, the IgG from hemodialysis patients had greater oxidized protein content, evidenced by more intense antibody binding to both the heavy and light chains. Western blot analysis of papain digests of oxidized IgG samples that were reprobed with an anti-Fc fragment antibody showed oxidative modification of the Fc fragment. These results suggest that patients with end-stage renal disease treated by hemodialysis have increased oxidized IgG in their plasma, including the Fc portion. Further studies are needed to see if this is due to enhanced production and/or decreased clearance of oxidized IgG.