—  SHORT COURSE  —

THE VALUE OF IMMUNOHISTOCHEMISTRY
IN THE ASSESSMENT OF BONE MARROW DISORDERS

Attilio Orazi, M.D., FRCPath. and Dennis P. O'Malley, M.D.




ANTI-LAMBDA AND ANTI-KAPPA LIGHT CHAIN

Both antibodies are polyclonal and are made in rabbits as antibodies to kappa and lambda light chains isolated from the urine of patients with Bence-Jones proteinuria. The antibodies react both with free light chains as well as light chains present in intact immunoglobin molecules. Kappa and lambda light chain staining is effective in both formalin fixed as well as B5 fixed bone marrow specimens and is not materially effected by decalcification. Heat-induced epitope retrieval improves the results. However, in some cases, there may be problems with nonspecific background staining. The kappa and lambda light chain reagents stain plasma cells and plasmacytoid lymphocytes. In bone marrow samples the antibodies are only capable of recognizing cytoplasmic light chains and not surface light chains. They are, therefore, of little value in the detection of B lymphocytes, which contain no cytoplasmic immunoglobin. Because of the homology between lambda light chain and the amyloid molecule, the lambda light chain reagent may stain amyloid in tissue sections in selected cases of amyloidosis (e.g. due to lambda 6). However, we do not believe that it is a reliable stain for amyloidosis.

Clinical cases in which anti-kappa and anti-lambda light chain staining are of value include:

  1. The detection and quantitation of plasma cells in bone marrow.
  2. The documentation of light chain restriction in multiple myeloma and related plasma cell dyscrasia and their separation from reactive plasma cell proliferations.
  3. The recognition of plasma cells in the marrow and their differentiation from other hematopoietic cells which they may resemble such as promyelocytes.
  4. The detection and documentation of plasma cell differentiation in immunocytomas and B cell immunoblastic lymphomas.
References
  • Wolf BC, Kumar A, Vera JD, Neiman RS: Bone marrow morphology and immunology in systemic amyloidosis. Am J Clin Pathol 86;84-88, 1986.
  • Wolf BC, Brady K, O'Murchadha MT, Neiman RS: An evaluation of immunohistologic stains for immunoglobin light chains in bone marrow biopsies in benign and malignant plasma cell proliferations. Am J Clin Pathol 44:90, 1990.