title: [Evaluation of the new Hevylite™ IgA assay for the diagnosis and follow-up of monoclonal gammopathies].
abstract: Multiple myeloma diagnosis and follow-up are based on monoclonal protein measurement. The estimation of monoclonal immunoglobulin production requires serum protein electrophoresis, immunoelectrophoresis and free light chain assay. However these classical assays have some limitations. Hevylite™ IgA (Binding Site) is a new nephelometric/turbidimetric assay allowing the IgA κ and IgA λ measurement. The aim of this study was to determine the performance of this assay, for the diagnosis and follow-up of myeloma patients at different stages. Sixty seven frozen sera from 26 patients were assayed. Total IgA, IgA κ, IgA λ concentrations, serum protein electrophoresis and serum immunofixation were performed at diagnosis and during follow-up. All myeloma patients had an abnormal IgA κ/IgA λ ratio at diagnosis. During disease monitoring, the IgA κ or IgA λ concentrations correlated well with the electrophoretic estimation of the monoclonal spike and the values of total IgA. Hevylite™ test was more sensitive than serum protein electrophoresis and provided numerical and reproductible assessment of the monoclonal and non-monoclonal isotype. The IgA κ/IgA λ ratio allowed early prediction of disease relapse. Hevylite™ is an interesting assay especially when the monoclonal IgA comigrates on electrophoresis with normal proteins making impossible a reliable densitometric estimation. Hevylite™ might become an important assay in the biological exploration of gammopathies.
authors.affiliation: Laboratoire de biochimie spécialisée, CHU de Dijon, France. daniela.lakomy@chu-dijon.fr
authors.forename: Daniela
authors.initials: D
authors.lastname: Lakomy
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Lemaire-Ewing
authors.forename: Damien
authors.initials: D
authors.lastname: Denimal
authors.forename: Jean-Noël
authors.initials: JN
authors.lastname: Bastie
authors.forename: Ingrid
authors.initials: I
authors.lastname: Lafon
authors.forename: Denis
authors.initials: D
authors.lastname: Caillot
mesh_terms: D001797:Blood Protein Electrophoresis / Q000379:methods; D016022:Case-Control Studies; D005500:Follow-Up Studies; D006405:Hematology / Q000379:methods; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007070:Immunoglobulin A / Q000032:analysis* / Q000097:blood; D007145:Immunoglobulin kappa-Chains / Q000032:analysis / Q000097:blood; D007146:Immunoglobulin lambda-Chains / Q000032:analysis / Q000097:blood; D047468:Immunoprecipitation / Q000379:methods; D057230:Limit of Detection; D008991:Monitoring, Physiologic / Q000379:methods*; D009101:Multiple Myeloma / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*; D010265:Paraproteinemias / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D012189:Retrospective Studies
chemical_list: D007070:Immunoglobulin A; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains
keywords: Hevylite assay; monoclonal IgA; multiple myeloma; protein electrophoresis; serum immunofixation