Hematologic Diagnostics Go with the Flow

(August 1, 2013) - Those diagnosing hematopathological disorders have been reaping the benefits of improved flow cytometry methodologies, though standardization of some techniques is still in the works.

Flow cytometry is being used to identify and evaluate clinical cases of various blood disorders. Researchers have also adapted other types of cellular analyses, such as cytogenetics and molecular genetics, in order to monitor disease states.

Anna Porwit, M.D., Ph.D., at the University of Toronto, has been immunophenotyping lymphoproliferative disorders with more than one malignant cell population. To investigate these diseases, Prof. Porwit and her colleagues use flow cytometry, which is a common immunophenotyping method in hematopathological diagnosis, to identify aberrant populations of cells in the blood and bone marrow.

As medical director of the university’s flow cytometry lab, Prof. Porwit instituted a 10-color flow cytometry method, using the Navios™ instrument from Beckman Coulter. Navios, which contains three lasers, allows Prof. Porwit and her colleagues to analyze 10-14 different antibodies simultaneously on the same cell. By using monoclonal antibodies with different connected fluorochromes, 10-14 different antigens can be assayed in one tube.

To study lymphoid malignancies, Prof. Porwit utilized two 10-color tubes of surface markers for B- and T-lymphocytes, respectively. She then evaluated kappa/lambda ratios separately in various B-cell subsets. Prof. Porwit noticed that in some lymphoma cases, there were two different pathological populations of B-cells or one of B- and one of T-cells in one sample, which was quite unusual because typically there is only a single aberrant population of cells.

In fact, Prof. Porwit and her colleagues identified a cohort of cases where there were clearly two different malignant populations. From 2,600 samples of blood, bone marrow, fine needle aspiration, and tumor cell suspensions, the researchers identified 43 samples showing two abnormal lymphoid populations—40 of which had two aberrant B-cell populations, the remaining three showing one B- and one T-cell aberrant population.

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