Advances in Monitoring and Prognostication for Lymphoma by Flow Cytometry

Introduction

Lymphomas comprise a heterogeneous group of diseases with variable clinical presentations, pathological features, and prognoses. In lymphoma diagnosis, flow cytometry (FC) can provide a detailed immunophenotypic profile of the lesional material and can provide a surrogate of clonality. Advantages of FC include a rapid turn-around time (within hours) and the ability to provide detailed data on subpopulations of cells. In certain lymphomas that may not have a tissue counterpart, for example, chronic lymphocytic leukemia (CLL), FC may constitute the primary diagnostic method.

Minimal/measurable residual disease (MRD) can be defined as persistent disease present posttherapy using methods more sensitive and specific than morphologic evaluation. Sensitivity levels in MRD can reach between 0.01% and 0.001% abnormal cells depending on the method utilized. ¹ In FC, the quality of MRD testing is influenced by a number of factors including the amount and quality of the specimen, the staining process (including reagent combinations used), the number of cells evaluated, and the approach to data analysis. ²

Recent advances in lymphoma treatment, namely targeted therapies such as therapeutic monoclonal antibodies and chimeric antigen receptor (CAR) T-cells, have practical implications for clinical FC.

This article addresses select concepts in monitoring and prognostication by FC in mature lymphomas, with information presented by lymphoma subtype.