Measurement of the cell proliferation rate of bone marrow erythroid precursors by flow cytometry: initial applications to multiple myeloma

Phase III, randomized, double-blind study of epoetin alfa compared with placebo in anemic patients receiving chemotherapy

PURPOSE

To determine whether weekly epoetin alfa could improve hemoglobin (HgB) levels, reduce RBC transfusions, and improve quality of life (QOL) in patients with advanced cancer and with anemia after receiving myelosuppressive chemotherapy.

PATIENTS AND METHODS

This double-blind, placebo-controlled study randomly assigned patients to placebo or epoetin alfa (Ortho Biotech, Bridgewater, NJ) 40,000 U subcutaneous weekly for 16 weeks. QOL, HgB, and RBC transfusions were measured pretreatment and monthly.

RESULTS

The study accrued 344 patients; 330 were assessable for efficacy and 305 were assessable for QOL. Placebo-treated patients had a mean increase in HgB of 0.9 g/dL (range, -3.8 to +5.3) compared with 2.8 g/dL (range, -2.2 to +7.5) for epoetin-treated patients (P < .0001). During the study, 31.7% of placebo-treated patients achieved a > or = 2 g/dL HgB increase compared with 72.7% of epoetin-treated patients (P < .0001). The incidence of RBC transfusion for placebo and epoetin treatment arms was 39.6% and 25.3% (P = .005), respectively. The placebo group received 256 units of RBCs compared with 127 units in the epoetin group (P < .0001). The incidence of toxicity in the groups was similar. Changes in the average QOL scores from baseline to the end of the study were similar in the two groups (P = not significant). The HgB responders (irrespective of treatment arm) had a mean change in Functional Assessment of Cancer Therapy (FACT) fatigue score from a baseline of +5.1 compared with -2.1 for the nonresponders (P = .006).

CONCLUSION

Epoetin alfa significantly improved HgB and reduced transfusions in this patient population. These results support the use of weekly epoetin alfa as an ameliorative agent for cancer-related anemia.

DRAQ5-based DNA content analysis of hematolymphoid cell subpopulations discriminated by surface antigens and light scatter properties

BACKGROUND

Analysis of cell cycle kinetics offers important information regarding the behavior of normal and neoplastic cells. Most often, cell cycle determinations by flow cytometry (FCM) have been performed using whole-sample analysis with intercalating dyes like propidium iodide (PI). The cell cycle phase assessment in individual cell subsets in heterogeneous samples is best performed using combined antigen/scatter and DNA analysis. DRAQ5, a novel DNA binding dye that excites at 488 nm and emits in the far red spectra, rapidly penetrates intact live cells while preserving their light scatter properties and expression of surface antigens. We evaluated the ability of this dye to measure cell cycle phases in a variety of clinical hematolymphoid samples.

METHODS

We first compared whole sample DRAQ5 and PI cell cycle analyses in 26 clinical hematolymphoid samples. Next, we analyzed cell subpopulations in 39 samples of nonpathologic bone marrow by performing simultaneous CD45/CD34 and DRAQ5 staining. We assessed cell cycle characteristics specific to each population identified by CD45/CD34/side light scatter: lymphocytes, monocytes, immature and mature granulocytes, nucleated erythroid cells, and early precursors.

RESULTS

Whole sample DNA cell cycle analyses by DRAQ5 and PI showed no significant differences in S-phase. DRAQ5, however, produced slightly larger coefficients of variation. DRAQ5-based DNA content analysis was easily performed on the distinct marrow cell subpopulations, since light scatter and antigen expression were completely preserved. Significant differences in S-phase were noted between subpopulations of cells exhibiting different degrees of maturation.

CONCLUSIONS

Because of its simplicity of use, excitability with 488 nm lasers, and the ability to stain viable cells, DRAQ5 should prove most useful in the kinetic evaluation of normal and neoplastic hematolymphoid cell subsets identified by light scatter and antigenic expression.

Application of flow cytometric techniques to veterinary clinical hematology

Flow cytometry has emerged as a major new technology in veterinary clinical laboratories. Flow cytometers in current use include stand-alone instruments and cytometers incorporated into hematology analyzers. Flow cytometers offer rapid and quantitative analysis of a variety of cell types based on cell size, molecular complexity, and antigenic composition. Therefore, flow cytometry complements and extends knowledge that can be obtained by light microscopy. Stand-alone instruments are very flexible, however, this flexibility opens the instrument to obtaining invalid or misleading results. The recent development of monoclonal antibodies specific for epitopes on blood cells of food and companion animals has greatly expanded the spectrum of tests with potential clinical application. Tests that appear to have the greatest potential for routine application include reticulocyte and reticulated platelet enumeration, detection of erythrocyte-bound immunoglobulin, immunophenotyping of leukemias and lymphomas, and bone marrow differential cell counting. This report will briefly review the technical aspects of flow cytometry and then focus on techniques with present or potential application to the veterinary clinical laboratory.