title: Dual surface immunoglobulin light-chain expression in B-cell lymphoproliferative disorders.
abstract: BACKGROUND
  Mature B lymphocytes exhibit allelic exclusion in which only a single class of immunoglobulin heavy chain and a single class of light chain, either kappa or lambda, are expressed. There have been several reports indicating that double light-chain gene rearrangements or dual light-chain expression can occur in B-cell malignant neoplasms, including chronic lymphocytic leukemia. Currently, it is a common notion that demonstration of light-chain restriction in a B-cell population is generally considered proof of monoclonality and indicates malignancy.
  
  
  OBJECTIVE
  To increase awareness of the existence of the dual kappa/lambda immunoglobulin light-chain expressing B-cell leukemia/lymphoma, to emphasize the importance of visual inspection of flow cytometric data, and to present the guidelines for flow cytometric interpretation of dual kappa/lambda coexpressing populations.
  
  
  METHODS
  Through comprehensive literature review, this article discusses the current understandings regarding the dual light-chain expression in B-cell neoplasms, the cellular and molecular mechanisms, and the clinical and diagnostic implications of dual light-chain expression.
  
  
  CONCLUSIONS
  Dual kappa/lambda light-chain expressing B-cell leukemia/lymphomas do exist. Recognition of the dual kappa/lambda light-chain expression on B cells has diagnostic implication in leukemia/lymphoma immunophenotyping.
authors.affiliation: Department of Pathology and Laboratory Medicine, Boston Medical Center, Boston, MA 02118, USA. dongsheng.xu@bmc.org
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Xu
mesh_terms: D001402:B-Lymphocytes / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism; D002999:Clone Cells; D005434:Flow Cytometry; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain; D017408:Guidelines as Topic; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000235:genetics / Q000378:metabolism*; D007146:Immunoglobulin lambda-Chains / Q000235:genetics / Q000378:metabolism*; D008232:Lymphoproliferative Disorders / Q000276:immunology* / Q000378:metabolism / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains