[Serum immune complexes in rheumatoid arthritis (a study of 100 cases). Comparison of the results obtained by four...

The detection of serum immune complexes in cases of rheumatoid arthritis (RA) was performed using four different detection techniques: cryoglobuline (CG), the polyethylene glycol C1q test (PEGC1q), the 125I labelled C1q test (C1qBA) and the detection of anticomplement power (ACP). CG, PEGC1q, and C1qBA are more often positive in cases of sero-positive RA than in sero-negative RA (p less than 0,001 for each test). There are significant and relatively concordant correlations between the positivity of these three tests and certain clinical and laboratory parameters in particular, the level of rheumatoid factor (p less than 0,001) and the presence of extra-articular manifestations. When ACP is found in cases of RA of recent onset, it is associated, in sero-positive cases of RA, with the presence of immune complexes and a more severe form of the disease.