Summary
Laser nephelometry is a sensitive technique for measuring the degree of light scatter caused by the interaction of rheumatoid factors with heat aggregated human IgG. In measuring the rheumatoid factor (RF) level in rheumatoid serum and synovial fluid, it was found that nephelometry measured the combined amounts of IgM-RF and IgG-RF. However, on an equivalent weight basis, IgM-RF produced at least 17 times more scatter than IgG-RF. Low molecular weight IgM-RF had minimal light scattering activity in this assay. The total serum RF level, measured by nephelometry and expressed in terms of μg/ml of IgM-RF equivalents, correlated strongly with IgM-RF measured by solid phase radioimmunoassay (r=0.97, n=30, P<0.001) and an equation was derived to equate the two variables. It is concluded that the nephelometric RF test is a simple and rapid method to measure the total polyclonal RF level in various biological fluids, although monoclonal or an occasional polyclonal preparation of rheumatoid factor may give atypical results.
Similar content being viewed by others
References
Virella G, Waller M, Fudenberg HH (1978) Nephelometric method for determination of rheumatoid factor. J Immunol Methods 22:247–251
Weinblatt ME, Schur PH (1980) Rheumatoid factor detection by nephelometry. Arthritis Rheum 23:777–779
Roberts-Thomson PJ, Wernick RM, Ziff M (1981) Low molecular weight IgM in rheumatoid arthritis and other rheumatic diseases. Arthritis Rheum 24:795
Roberts-Thomson PJ, Neoh SH, Bradley J, Milazzo SC (1980) Circulating and intraarticular immune complexes in rheumatoid arthritis. A comparative study of the Clq binding and monoclonal rheumatoid factor assays. Ann Rheum Dis 39:349–353
Carson DA, Lawrence S, Catalano MA, Vaughan JH, Abraham G (1977) Radioimmunoassay of IgG and IgM rheumatoid factors reacting with human IgG. J Immunol 119:295–300
Chavin SI, Franklin EC (1969) Studies on antigen-binding activity of macroglobulin antibody subunits and their enzymatic fragments. J Biol Chem 244:1345–1352
Stone MJ, Metzger H (1968) Binding properties of a Waldenström macroglobulin antibody. J Biol Chem 243:5977–5984
Koopman WJ, Schrohenloher RE (1980) A sensitive radio-immunoassay for quantitation of IgM rheumatoid factor. Arthritis Rheum 23:302–308
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Roberts-Thomson, P.J., Wernick, R.M. & Ziff, M. Quantitation of rheumatoid factor by laser nephelometry. Rheumatol Int 2, 17–20 (1982). https://doi.org/10.1007/BF00541265
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00541265