Lambda Light Chain, IHC with Interpretation, Tissue

Laboratory assay overview

This test is used to evaluate the genetic expression of kappa and lambda light chains in fixed lymphoid tissue or bone marrow. An atypical ratio of kappa-expressing to lambda-expressing cells can help support a diagnosis of plasma cell neoplasm or B-cell lymphoma [1,2]. Immunoglobulin comprises 4 polypeptide chains: 2 heavy chains and 2 light chains (kappa or lambda). Light chains can be found on the surface of B cells and in the cytoplasm of plasma cells. Restricted expression of kappa or lambda light chains can be an indication of B-cell lymphomas or plasma cell neoplasms, which include monoclonal gammopathy of undetermined significance, plasmacytoma, and multiple myeloma. Multiple myeloma and other plasma cell neoplasms may cause amyloidosis, which can lead to organ dysfunction [3]. This test is used to evaluate the expression of kappa and lambda light chains when fixed tissue or a limited amount of biopsy tissue is obtained. When sufficient fresh tissue is available, flow cytometry can be used to achieve high sensitivity over a broad dynamic range of protein expression. Serum kappa/lambda light chains can also be used to assist in the diagnosis of plasma cell disorders as well as in monitoring disease activity and treatment. Kappa/lambda light chain in situ hybridization cannot detect small amounts of surface immunoglobulin present on most resting B cells [1,3]. Interpretation of this test is performed by a qualified pathologist. The significance of the result should be determined in the context of pertinent clinical and family history, findings of physical examinations, and other diagnostic tests. References 1. Guo L, et al. Mod Pathol. 2018;31(3):385-394. 2. Weiss LM, et al. Am J Pathol. 1990;137(4):979-988. 3. National Cancer Institute. Plasma cell neoplasms (including multiple myeloma) treatment (PDQ®)-health professional version. Accessed September 1, 2021. https://www.cancer.gov/types/myeloma/hp/myeloma-treatment-pdq