Increased C1_q binding immune complexes in felty's syndrome

Abstract

Sera from patients with Felty's syndrome (FS) and rheumatoid arthritis (RA) were examined for the presence of circulating immune complexes (IC) by using the '=I-Clq binding and monoclonal rheumatoid factor (mRF) techniques. Of 15 patients with FS, 9 (60%) had high 'z51-Clq binding as compared to 3 of 26 RA patients (12%). The average Clq binding was significantly higher in the FS patients than in the RA patients without FS. Clq binding in both FS and RA patients was significantly higher than a group of 90 normal controls. In addition, serum C4 levels were significantly lower in the FS patients than in the RA patients. In contrast to these findings, IC levels in FS and RA patients were very similar when measured by the mRF technique. These studies indicate that FS patients have higher levels of complement-fixing IC in their sera than RA patients without FS. These findings raise the possibility that the complement-fixing IC found in these patients may play a role in the pathogenesis of the neutropenia of FS.

IgE class immune complexes in Felty's syndrome: characterisation of antibody activities in isolated complexes.

“…We frequently found heat resistant anti-IgE activity both in sera and in IC (11 sera and 3 PEG fractions). The principle of anti-IgE determination is based on an assumption that practically all IgE molecules in samples are immunochemically destroyed during the 56°C incubation for 4 Whether IgE class autoantibodies, anti-IgE factors, and the consequent formation of IgE complexes are the result of a permanent polyclonal activation in FS or an anomaly of the separate regulation of IgE production and metabolism in FS is unknown. These are questions for further study.…”