High serum beta-2-microglobulin levels and circulating immune complexes containing beta 2m and anti-beta 2m antibodies in Felty's syndrome.
Serum beta-2-microglobulin (beta 2m) levels, incidence and levels of anti-beta 2m autoantibodies, and quantity of circulating macromolecular complexes containing beta 2m were studied in patients with Felty's syndrome (FS), joint-restricted rheumatoid arthritis (RA), and healthy controls. The serum beta 2m concentrations detected in the FS group (6.95 +/- 2.9 mg/liter) greatly exceeded those of the RA group (3.4 +/- 1.2 mg/liter) and the control group (1.42 +/- 0.69 mg/liter). Autoantibodies to beta 2m were frequent in the FS group. Circulating complexes containing beta 2m, prepared by precipitation in 3% polyethylene glycol, were detected in 65% of FS and 35% of RA patients. In the majority of these cases the solid-phase C1q purified immune complexes also contained beta 2m. Detection of anti-beta 2m antibodies in a significant part of complexes containing beta 2m suggests the presence of specific immune complexes in this fraction of FS and RA patients.
D000906:Antibodies / Q000032:analysis*; D000888:Antibodies, Anti-Idiotypic / Q000032:analysis*; D000936:Antigen-Antibody Complex / Q000032:analysis* / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000276:immunology; D001609:Beta-Globulins / Q000032:analysis*; D005258:Felty Syndrome / Q000276:immunology*; D006801:Humans; D001613:beta 2-Microglobulin / Q000032:analysis* / Q000276:immunology
D000906:Antibodies; D000888:Antibodies, Anti-Idiotypic; D000936:Antigen-Antibody Complex; D001609:Beta-Globulins; D001613:beta 2-Microglobulin