[Cryoglobulins and circulating immune complexes in rheumatoid arthritis. Clinical and biological correlations]

We studied circulating immune complexes using a test involving the precipitation of these complexes with polyethylene glycol 6000 at 2.5 percent, and characterization of the Clq bound in vivo to immunoglobulins in the serum of 126 healthy subjects, 95 hospitalized controls and 181 patients suffering from rheumatoid arthritis (RP). Likewise, the RP benefited from a study of cryoglobulins (CG). The PEG-Clq proved positive (PEG +) in 7 per cent of the healthy controls, 25 per cent in the seronegative RP. ThePEG & RP have a level of proteins, gammaglobulins, IgM and IgG that is higher than in patients in whom the test is negative. On the other hand, they have a lower level of C4. One CG was detected in 43 patients who were all PEG +. The level of CG is proportionate to the intensity of the articular inflammation, the sedimentation rate, the level of seric iron and that of hemoglobin. The composition of the precipitins obtained by activity of the PEG is very close to that of the CG.