[Selective binding in vitro of a modified form of the C3 component of complement to human erythrocytes].

C3 was bound to human erythrocytes from autologous plasma or from serum brought to low ionic strength (mu less than or equal to 0.03) and pH between 4.0 and 5.

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

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.