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 with rheumatoid arthritis (RA) were examined by nuclear magnetic resonance (NMR) and the results were compared to data obtained by ELISA.


METHODS
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 signal. The samples were also measured by ELISA.


RESULTS
The ratios of IgG2 in patients with RA measured by NMR were increased significantly compared to controls. However, there were no significant differences in the data determined by ELISA. Thus, a discrepancy exists in the analysis of IgG2 ratios between NMR and ELISA methods.


CONCLUSIONS
There was a discrepancy in the IgG2 ratios of patients with RA between NMR and ELISA methods, and we attribute this to a conformational difference in IgG2 in patients with RA.
Tokano
Y
Y
Department of Rheumatology and Immunology, Juntendo University, School of Medicine, Tokyo, Japan.
Endo
S
S
Hayashi
F
F
Harada
S
S
Kobayashi
S
S
Tsuda
H
H
Takasaki
Y
Y
Kyogoku
Y
Y
Arata
Y
Y
Okumura
K
K
Hashimoto
H
H
Hirose
S
S
D000328:Adult; D000936:Antigen-Antibody Complex / Q000032:analysis; D001172:Arthritis, Rheumatoid / Q000276:immunology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis* / Q000145:classification / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D012217:Rheumatoid Factor / Q000032:analysis
D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D012217:Rheumatoid Factor