title: Analysis of patients with γ-heavy chain disease by the heavy/light chain and free light chain assays.
abstract: BACKGROUND
  The objective of this study was to evaluate the performance of the heavy/light chain and free light chain immunoassays in patients with heavy chain disease, and to assess the ability of the heavy/light chain assay to measure and confirm the abnormal, truncated heavy chain.
  
  
  METHODS
  Frozen serum samples from 15 γ-heavy chain disease patients were tested for IgGκ, IgGλ, total IgG, free light chains, and M-spike concentrations.
  
  
  RESULTS
  The (Gκ+Gλ)/IgGtotal ratio for these 15 patients ranged from 0.02 to 0.80. The 10 patients with IgG concentrations above 1 g/dL all had ratios below 0.3 indicating that a substantial portion of IgG was not quantitated by the Gκ and Gλ reagents. The average M-spike was 1.61 g/dL and the average calculated abnormal γ-chain concentration was 2.94 g/dL. Additionally, free light chain analysis revealed the presence of monoclonal free κ light chain in three of the 15 patients.
  
  
  CONCLUSIONS
  This study demonstrates utility of a nephelometric assay to identify truncated immunoglobulin heavy chains in γ-HCD and that 20% of these patients also have monoclonal free light chain.
authors: Erin
authors: E
authors: Kaleta
authors: Robert
authors: R
authors: Kyle
authors: Raynell
authors: R
authors: Clark
authors: Jerry
authors: J
authors: Katzmann
mesh_terms: D004586:Electrophoresis; D006362:Heavy Chain Disease / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007118:Immunoassay; D007143:Immunoglobulin Heavy Chains / Q000097:blood*; D007147:Immunoglobulin Light Chains / Q000097:blood*; D007145:Immunoglobulin kappa-Chains / Q000097:blood; D007146:Immunoglobulin lambda-Chains / Q000097:blood
chemical_list: D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains