Evaluation of erythropoiesis after bone marrow transplantation: quantitative reticulocyte counting

Abstract

Erythroid regeneration is an important and separate element in the engraftment process in allogeneic and autologous bone marrow transplantation (alloBMT, autoBMT). Qualitative visual reticulocyte counting has proved inadequate in the evaluation of erythropoiesis after BMT but automated flow cytometry now allows the reliable quantitation of reticulocytes even to very low levels. Reticulocyte counts and highly fluorescent reticulocyte (HFR) counts (very early reticulocytes) were estimated daily in recipients of 22 autoBMT and 14 alloBMT using a Sysmex R-1000 automated reticulocyte counter. Marrow ablation caused an immediate and rapid fall in both the reticulocyte count and the HFR. Measurable numbers of reticulocytes persisted throughout the hypoplastic period, but HFR fell to zero in the majority of both the autoBMT and alloBMT. HFR rose significantly after a median time of 14 d post-autoBMT, and 12 d post-alloBMT. Attainment of 15 x 10(9)/l reticulocytes and 0.5 x 10(9)/l HFR at day 21 post-transplant was associated with ultimate engraftment in 100% cases. Inadequate engraftment was seen in the majority of patients whose responses fell below these levels. Graft-versus-host disease was associated with a transient slight reduction in reticulocyte count. Neither episodes of infection nor blood transfusions had any significant impact on trends of reticulocytes or HFR. Automated flow cytometric reticulocyte counting has been shown to provide an accessible measure of erythroid activity which may be of predictive value in the management of patients following bone marrow transplantation.

Recovery from neutropenia can be predicted by the immature reticulocyte fraction several days before neutrophil recovery in autologous stem cell transplant recipients

“…These studies however, utilized different methods for measuring immature reticulocytes and/or compared the IRF to ANCX500/ml and not to the more clinically relevant ANCX100/ml (Table 4). 10,[15][16][17][18][19][20][21][22] Since there are different types and manufacturers of blood count analyzers with different reference values and calibration parameters, 9,23 end points such as doubling (IRF-D) or normalization (IRF-N) of the IRF can be used regardless of equipment and would simplify and standardize result interpretation among investigators.…”

Flow cytometric reticulocyte maturity index: A useful laboratory parameter of erythropoietic activity in anemia

“…The parameter has also been reported to distinguish iron deficiency anemia from anemia of chronic disease (34). A similar RMI parameter can be derived from the Sysmex R series' dedicated reticulocyte analyzers based on the fluorescence intensity of auramine 0 reticulocyte staining, which has also been reported to be an early predictor of bone marrow engraftment (3,9,19,22) and parallels the increase in circulating CD34+ cells following granulocyte colony-stim-0 1 9 9 5 Wiley-Liss, Inc.ulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) priming prior to peripheral stem cell harvesting (27,29). However, no information on the RMI and its relationship to standard hematologic red cell parameters in a large series of anemic patients has been reported.…”

“…The parameter has also been reported to distinguish iron deficiency anemia from anemia of chronic disease (34). A similar RMI parameter can be derived from the Sysmex R series' dedicated reticulocyte analyzers based on the fluorescence intensity of auramine 0 reticulocyte staining, which has also been reported to be an early predictor of bone marrow engraftment (3,9,19,22) and parallels the increase in circulating CD34+ cells following granulocyte colony-stim-0 1 9 9 5 Wiley-Liss, Inc.…”

Immature platelet fraction for prediction of platelet engraftment after allogeneic stem cell transplantation

“…Although reticulocyte counts performed by automated flow cytometric methods provide a good indicator of erythropoietic activity that may predict bone marrow regeneration, the duration, until increases in reticulocytes are seen, is usually later than or equal to that of neutrophils after transplantation. [4][5][6] Analysis of chimerism using fluorescence in situ hybridization (FISH) or polymerase chain reaction (PCR)-based methods can allow earlier demonstration of engraftment after transplantation, 7 but is costly and therefore unsuitable for routine monitoring.…”