Association between IgM response to IgG damaged by glyoxidation and disease activity in rheumatoid arthritis

Objective. To determine the association of serum IgG advanced glycation end products (AGE) and IgM anti-IgG-AGE antibodies with clinical measurements o f rheumatoid arthritis (RA) disease activity. Methods. The study group consisted of 62 patients with RA and 16 control pa tients with osteoarthritis. Patient derived variables included perceived di sease activity (10 cm visual analog scale, VAS) and Health Assessment Quest ionnaire (HAQ) results. Clinical measures of RA activity consisted of tende r and swollen joint counts and a physician evaluation of disease activity ( by VAS) as well as history of nodules, bone erosions, Sjogren's syndrome, a nd vasculitis documented by chart review. Patient sera were evaluated for g lucose, glycosylated hemoglobin, and presence of RE IgG-AGE and IgM anti-Ig G-AGE. The nitroblue tetrazolium colorimetric and aminophenyl boronic acid methods were used for measurement of IgG-AGE, along with an ELISA for measu rement of IgM anti-IgG-AGE. Results. Significant correlations were found between the presence of IgM an ti-IgG-AGE and clinical measurements of swollen joint count and physician V AS. Conclusion. IgM anti-IgG-AGE appears to be associated with clinical measure ments of RA activity and represents a new marker of more active disease in RA.