The presence of anti-protein A antibodies in patients with rheumatoid arthritis.
Sixteen patients with rheumatoid arthritis (RA) were examined for the presence of anti-protein A antibodies. The F(ab')2 preparations from five RA patients showed significant binding to IgG-free protein A on ELISA. The protein A binding was further examined by immunoblotting. The F(ab')2 preparations of high protein A-binding protein gave a specific reaction with IgG-free protein A on nitrocellulose paper. This demonstrates the presence of anti-protein A antibodies in patients with RA. Those RA patients with anti-protein A antibodies had more active disease as judged by the Lansbury's activity index. The level of serum rheumatoid factor (RAHA) was significantly higher in patients with anti-protein A antibodies than in those without anti-protein A antibodies.
Takeuchi
T
T
Second Department of Internal Medicine, Saitama Medical Center, Saitama Medical School, Japan.
Hosono
O
O
Koide
J
J
Amano
K
K
Sekine
H
H
Abe
T
T
D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000032:analysis*; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001665:Binding Sites; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007141:Immunoglobulin Fc Fragments / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D008297:Male; D008875:Middle Aged; D012217:Rheumatoid Factor / Q000096:biosynthesis; D013205:Staphylococcal Protein A / Q000276:immunology*
D000907:Antibodies, Bacterial; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D013205:Staphylococcal Protein A; D012217:Rheumatoid Factor