A HIDDEN IMMUNOGLOBULIN G2 IN PATIENTS WITH RHEUMATOID-ARTHRITIS DETECTED BY NUCLEAR-MAGNETIC-RESONANCE

Objective. The ratios of immunoglobulin (Ig) G1 and IgG2 in patients w ith rheumatoid arthritis (RAJ were examined by nuclear magnetic resona nce (NMR) and the results were compared to data obtained by ELISA. Met hods. The IgG of 11 patients with RA were prepared with a DE-52 column and the specific signals for IgG1 and IgG2 were measured by NMR. The ratios of IgG1 and IgG2 were determined by the intensity of this signa l. The samples were also measured by ELISA. Results. The ratios of IgG 2 in patients with RA measured by NMR were increased significantly com pared to controls. However, there were no significant differences in t he data determined by ELISA. Thus, a discrepancy exists in the analysi s of IgG2 ratios between NMR and ELISA methods. Conclusion. There was a discrepancy in the IgG2 ratios of patients with RA between NMR and E LISA methods, and we attribute this to a conformational difference in IgG2 in patients with RA.