Diagnosis and classification of B-cell non-Hodgkin lymphomas. The role of multiparameter flow cytometry

Immunophenotyping is a routine method to evaluate B-cell non-Hodgkin lymphomas. Flow cytometry plays a complementary role in diagnosis and classification of these types of lymphomas, since combination of morphologic, immunophenotypic and genotypic features is needed to correctly classifying each disease entity. Multiparameter flow cytometry, which is now carried out with routine combinations of six to eight monoclonal antibodies, allows identifying even small lymphomatous cell populations on the basis of aberrant B-cell marker expression and clonality. The immunophenotypic patterns obtained by multiparameter flow cytometry are useful to correctly diagnose most of cases of specific subtypes of B-cell non-Hodgkin lymphomas and to discover peculiar clinical presentations, such as discordant and composite lymphomas. Immunophenotypic variability, however, characterizes B-cell lymphomas. Therefore, flow cytometry should always be used in combination with other techniques to correctly classify each disease entity. Finally, multiparameter flow cytometry is characterized by high sensitivity in detecting residual disease.