Immunophenotyping by flow cytometry is a solution to determine the type of lymphoma as panels of markers can be run to track the aberrant expression of antigens on lymphocytes.
Immunophenotyping
When a lymphoproliferative disorder remains a significant possibility after clinical evaluation, cell surface and some intracellular phenotyping of lymphocytes is warranted.
Flow cytometry allows the screening of peripheral blood mononuclear cells (PBMCs), bone marrow and other fluids such as cerebrospinal fluid (CSF) to monitor not only the percentage of lymphocytes positive for a specific antigen but also the density of the antigens. Normal PBMC composition includes approximately 10% B cells, 80% T cells and 10% NK cells. Variations in these cell populations are cause for suspicion of lymphoproliferative disease. Specific flow cytometry panels can be run to assess each of these populations. Flow cytometry can also be used for phenotyping other lymphoid cells and tissues, including lymph nodes, skin, organs and brain as well as body fluids.
Diffuse large B cell lymphoma
Diffuse large B cell lymphoma (DLBCL) is the largest category of lymphoma and accounts for 30 to 40% of adult NHL in western countries. This category of lymphoma can be a progression from another lymphoid malignancy such as follicular lymphoma (FL) or chronic lymphocytic leukemia (CLL). It is characterized by large lymphocytes that can be detected by flow cytometry. A standard immunophenotyping panel for DLBCL includes pan-B cell markers (CD19, CD22, CD79a), germinal center marker CD10, and proliferation marker Ki67. A high Ki67 indicates increased proliferation of the malignant lymphoma cells.6,7
T cell/NK cell neoplasms
Abnormalities in pan-T cell antigens, e.g., CD2, CD3, CD5, CD7, are indicative of a T cell lymphoproliferative disorder.8 T cell non-Hodgkin lymphoma (T cell NHL) represents about 12% of all non-Hodgkin lymphomas.9
T/NK cell neoplasms represent a small portion of lymphomas. They display an aberrant T cell or NK cell phenotype. Chronic lymphoproliferative disorders of NK cells (CLPD-NK) are rare heterogeneous disorders with continuous expansion of NK cells in peripheral blood, expressing CD16 and low levels of CD56 and CD57.10 Peripheral T cell lymphoma is an uncommon heterogeneous malignancy, accounting for less than 15% of all lymphomas.11
Flow cytometry–based applications
BD Biosciences offers a large portfolio of single-color antibody reagents that span across a range of specificities and dyes that can help in the characterization of hematologic neoplasia. These panels are to be verified and validated by the lab.
Furthermore, BD Biosciences provides the BD OneFlow™ Solution, comprising a comprehensive set of reagents, setup beads, protocols and assay templates, to help standardize leukemia and lymphoma immunophenotyping. This can improve laboratory efficiency and enable reliability and accuracy of results.12,13