Biomedical subjects
W C Levin
Publications and source records attributed to W C Levin.
Idiopathic (asymptomatic) monoclonal gammopathies.
Asymptomatic forms of monoclonal gammopathies (MG) are recognized with increasing frequency; their recognition and differentiation from the symptomatic forms of MG appear imperative, since the therapeutic approaches are different. Available clinical and laboratory indexes lack specificity required for useful and practical discrimination; presently, we must still rely on the timecourse monitoring of such laboratory values as hemoglobin levels, M-protein concentrations, and presence of Bence Jones proteins. Elucidation of histocompatibility A and W antigenic profiles, as well as the functions and kinetics of B-lymphocytes from such patients, appear most promising. Evidence of the causative role of extrinsic and intrinsic antigenic stimulation in MG production is increasing; segregation into two distinct concentration ranges of M-proteins in the asymptomatic and symptomatic groups suggests two control levels of the expression of immune response (Ir) genes, due to partial or complete derepression of the latent Ir gene function, reflecting "partial" (asymptomatic, benign MG) and "complete" (symptomatic, malignant MG) monoclonal immune responders.
Methodologic differences in values for M-proteins in serum, as measured by three techniques.
Accurate and reproducible measurement of M-proteins is essential for managing patients with monocional gammopathies, but serum protein electrophoresis, radial immunodiffusion, and electroimmunodiffusion yield comparatively divergent results. We have studied these differences and their causes. Sera from cases of IgG-monoclonal gammopathy, IgA-monoclonal gammopathy, and IgM-monoclonal gammopathy were assayed by each of the three techniques. Results indicated inter-method discrepancies as great as fivefold for all proteins studied. For IgG-monoclonal gammopathy, radial immunodiffusion values were less consistently so. For IgA-monoclonal gammopathy, both radial immunodiffusion and electroimmunodiffusion gave lower results than did serum protein electrophoresis. For IgM-monoclonal gammopathy, results were variable, but values by radial immunodiffusion tended to be higher than, and electroimmunodiffusion comparable to, those for serum protein electrophoresis. The differences were not correlated with protein abundance, serum freshness, immunoglobulin class, light-chain type, ultracentrifugal characteristics, or electrophoretic mobility. Clearly, values for M-protein concentration depend on the techniques used to obtain them. We postulate that subclass differences may contribute to the diversity of radial immunodiffusion results, and that for electroimmunodiffusion the fixed electrophoretic mobility of M-proteins leads to unpredictable results. We conclude that serum protein electrophoresis is the best of the three assay techniques for M-proteins.