The effect of GM-CSF on reticulocytes, haemoglobin and haematocrit in patients receiving chemotherapy for solid tumours

Improvement of detection specificity of Plasmodium-infected murine erythrocytes by flow cytometry using autofluorescence and YOYO-1

BACKGROUND

Microscopic analysis of blood smears is currently the most frequently used method to measure parasitemias in experiments of drug efficacy in murine models of malaria. However, it is subjective and labour intensive, which preclude its utilization in large-scale evaluation programs. Flow cytometry is an alternative method, but due to the limited specificity achieved with the currently available techniques, it has not been widely used in murine models of malaria during preclinical evaluation. We describe a new flow cytometric method based on the differences of autofluorescence and DNA content measured after staining with YOYO-1 that are observed in infected erythrocytes compared with noninfected erythrocytes.

METHODS

Samples of blood from Plasmodium yoelii-infected animals were fixed with glutaraldehyde, incubated with RNAase, and stained with YOYO-1 in 96-well plate format. After acquisition, erythrocytes gated in logarithmic side/scatter plots were analyzed in bidimensional FL-2/YOYO-1 plots in comparison with unidimensional YOYO-1 analysis.

RESULTS

The infected erythrocytes showed a characteristic pattern of staining different from that of noninfected erythrocytes. In routine evaluation, the limit of sensitivity was 0.01% and the measurements of parasitemia were linear at parasitemias above 0.1%. Interestingly, using this approach, infected reticulocytes could be differentiated from infected normocytes.

CONCLUSIONS

The method described is robust, increases the specificity and sensitivity of detection in routine testing, and is especially well suited for detection of low parasitemias in murine models of malaria.

Persistent nucleated red blood cells in peripheral blood is a poor prognostic factor in patients undergoing stem cell transplantation

We compared detection rates and counts of nucleated red blood cell (NRBC) in the peripheral blood of survivors and nonsurvivors (total 44 patients) of stem cell transplantation. The rate of NRBC detection increased to 79.5% after transplantation. After engraftment, the detection rate of NRBC decreased to 17.0% in survivors, but increased to 100% in nonsurvivors. The NRBC count increased after transplantation in both groups. This increase was transient in survivors, but increased after engraftment in nonsurvivors. The mean NRBC count after engraftment was 872 vs. 40.3 for nonsurvivors vs. survivors, respectively. At postengraftment, all patients who were negative for NRBC survived, but 10 of the 15 patients who were positive for NRBC died (66.7%). The survival rates of patients with a NRBC count >200 x 10(6)/l were significantly lower than those of patients whose counts were <100 x 10(6)/l. These data indicated that persistent NRBC in peripheral blood is a poor prognostic factor, and suggested that monitoring NRBC after SCT might provide useful clinical information.

Reticulocyte analysis by flow cytometry and other techniques

Enumeration of peripheral blood reticulocytes is an essential part of the diagnosis and management of anemic patients, since the number of reticulocytes in the peripheral blood reflects the erythrocytic activity of the bone marrow. Reticulocyte enumeration using flow cytometric methodology is rapidly replacing the inaccurate, imprecise manual counting technique used in the past. This article explores the pathophysiology of the reticulocyte, the various means of counting reticulocytes, and the diverse clinical applications of reticulocyte data.