Circulating immune complexes in collagen diseases.

: In a group of 75 patients with collagen diseases a study was carried out for the structural characterization of the circulating immune complexes (CIC) and the eventual detection of a correlation between these complexes and various serum biologic parameters. The results obtained have demonstrated: (a) the great variability of the structure of immune complexes even in the same type of disease and (b) the lack of correlation between the concentration of components in the CIC structure and the level of the same components in the serum. The lack of correlation may be explained by the great variety of immune complexes formation and the increase of any of the serum immunoglobulins does not necessarily mean its total or partial aggregation in the CIC structure.