[Rheumatoid factors, C-reactive protein and circulating immunocomplexes: laser-nephelometric determination using the latex aggregation method. Preliminary evaluation in rheumatoid arthritis]

C-reactive protein and rheumatoid factor assays are relevant laboratory parameters, among the most used in the clinical practice, being very useful in diagnosing and "monitoring" rheumatic diseases. A quantitative test to detect these two serum proteins is an important, more specific, new tool for clinical medicine. In our study we evaluated two new laser nephelometric assays, both quantitative, based on the agglutination of polystyrene latex particles, able to show serum concentration of CRP and RF. With a similar technique we tested the presence of circulating immune complexes. We performed our tests in a group of patients with rheumatoid arthritis, other autoimmune diseases, and healthy blood bank donors assaying simultaneously, whenever possible, the "classic" Rose-Waaler and RA tests. We found both methods easy to perform, well correlating with the semi-quantitative techniques and highly reproducible.