[Application of Flow Cytometry in Clinical Laboratories and Its Future Direction, Focusing Upon Multicolor Flow Cytometry].

Flow cytometry (FCM) has been introduced into clinical laboratories to determine the lineage and functional stage of differentiation of hematopoietic tumor cells using multiple immunophenotypic markers. Multi-parametric analysis, which simultaneously measures multiple cellular characteristics, not only provides a large amount of novel information for each sample studied, but also requires a reduced volume of the specimen and avoids redundancies of reagents within antibody panels. Through a series of novel developments in FCM hardware, software, and dye-chemistry, recently developed multicolor flow cytometers are capable of detecting 10 or more fluorochromes simultaneously and expeditiously, taking advantage of not only cluster analysis but also detecting rare cellular populations within complex materials. In this study, we applied the multicolor FCM technology for: i) T-cell lineage assessment in early T-cell precursor acute lymphoblastic leukemia, ii) detection of a rare neoplastic population in angioimmunoblastic T-cell lymphoma composed of a complex mixture of cells, iii) assessment of bone marrow infiltration of B-cell lymphoma, and iv) sensitive detection of multiple myeloma cells with the use of a combination of antibodies, which is applicable to monitoring the response to treatment.