Immune complexes in early arthritis. II. Immune complex constituents are synthesized in the synovium before rheumatoid factors
Jones, V.E.; Jacoby, R.K.; Cowley, P.J.; Warren, C.
Clinical and Experimental Immunology 49(1): 31-40
1982
ISSN/ISBN: 0009-9104 PMID: 7127902 Document Number: 184513
Synovial fluids and paired sera taken from patients either before, after or at the time of diagnosis of definite rheumatoid arthritis (RA) were compared with samples from patients with unclassified inflammatory arthropathies (IA). Raised levels of immune complexes (IC) were detected in some RA patients by C1q [complement component 1q] binding activity but in the majority of both RA and IA patients by the platelet aggregation test; levels were usually higher in joint fluids than in sera. IgM rheumatoid factors (RF) and IgA RF were lower in synovial fluids but IgG RF levels were similar in matched samples. Synovial fluid to serum albumin ratios were used to estimate synovial permeability (inflammation) and then to calculate which patients synthesized macromolecules locally in the synovium. Local synthesis of RF was detected in a greater proportion of RA than IA patients and only 2 patients formed RF locally in the first months of symptoms. Half the patients in both groups appeared to synthesize or trap IC constituents and in many patients there was evidence of local synthesis within 6 mo. after their symptoms had started. Local synthesis of large amounts of RF is uncommon in the early stages of RA but IC of unknown composition are synthesized or localized in the affected joints of many patients with RA and inflammatory arthropathies shortly after their symptoms appear.