Evaluation of reticulated platelets in patients with sickle cell diseases.

BACKGROUND AND PURPOSE: Reticulated platelet (RP) count provides an estimate of thrombopoiesis. The objective was to evaluate RP in patients in different stages of sickle cell disease (SCD) and to determine the relationship between interleukin-6 (IL-6), interleukin-3 (IL-3) and thrombopoietin (TPO) and RP count and degree of activation. METHODS: Eighty-nine adult patients with SCD were studied: 38 were in the steady state, 27 in hemolytic crisis (HC) and 24 in vaso-occlusive crisis (VOC). RPs and activated platelets were analyzed by flow cytometry. Soluble P-selectin, IL-6, IL-3 and thrombopoietin (TPO) levels were measured by ELISA tests. RESULTS: The patients in VOC had a higher absolute number of RPs and CD62P+ platelets than did the control group or patients in the steady state. A significant correlation was observed between the absolute number of CD62P+ platelets and RPs in patients in the steady state, HC and VOC. In the steady-state group of patients, the level of soluble P-selectin was found to be dependent on the RP values. IL-3 and TPO serum levels were higher in patients in the steady state, HC and VOC than in the control group. IL-6 serum levels were higher in HC and VOC patients than in the control group and higher in patients in the steady state than in the VOC group. CONCLUSION: Our results suggest that PRs contribute to the vaso-occlusive process in sickle cell disease. Increased interleukin serum levels probably indicate that inflammatory process is involved in the vascular-occlusive phenomenon. However, it appears that these inflammatory mediators do not have an effect on thrombopoiesis in sickle-cell-disease patients.

Hematopoietic progenitor cells (HPC) and immature reticulocytes evaluations in mobilization process: new parameters measured by conventional blood cell counter.

Monitoring the timing of leukapheresis in peripheral blood stem cells (PBSC) mobilization is an important clinical decision that requires an accurate analytical tool. The present study assessed hematopoietic progenitor cells (HPC) and immature reticulocyte fraction (IRF) counts provided by a routine automated blood counter as potential parameters for predicting the appropriate time for harvesting. The HPC and IRF values were compared with white blood cell (WBC) and CD34+ cell counts obtained by flow cytometry in 30 adult patients with hematological malignancies undergoing PBSC mobilization. It was observed that there was a significant correlation between HPC counts and CD34(+) cells in peripheral blood counts (r=0.61, P=0.0003) and between the number of HPC and CD34+cells collected by leukapheresis (r=0.5733, P=0.0009). Comparing HPC, IRF, WBC, and CD34+ cells parameters as a sign of hematological recovery showed that the raise in immature reticulocytes counts preceded the increase of WBC (P=0.0002), HPC (P=0.0001), and CD34(+) (P=0.0001) cells in peripheral blood counts. According to our results, HPC and IRF parameters may be integrated into clinical protocols to evaluate the timing of leukapheresis. IRF, as previously demonstrated in bone marrow transplantation, is the earliest sign of hematopoietic recovery in mobilization process.

Platelet larger cell ratio (P-LCR) in patients with dyslipidemia.

We have described preliminary results of platelet larger cell ratio (P-LCR) analysis, provided by an automated hematology analyzer in patients with hypercholesterolemia and/or hypertriglyceremia. P-LCR values were significantly higher in patients (n = 41) than in control normal group (n = 20) (P < 0.0001). Larger platelets are more reactive and contribute to vasooclusive events in patients with dyslipidemia. P-LCR may be used as an indicator of risk factor for thromboembolic ischemic events.

Immature reticulocytes as an early predictor of engraftment in autologous and allogeneic bone marrow transplantation.

The purpose of this study was to evaluate reticulocyte parameters by means of flow cytometric reticulocyte counting in a group of patients who had undergone autologous and allogeneic bone marrow transplantation (BMT). The pattern of reticulocyte response and the predictive value of absolute neutrophil count (ANC), platelet count, number of CD34+ cell infused and graft source for reticulocyte response were studied. We compared absolute reticulocyte count (RetAbs), mean fluorescence index (MFI) and mean reticulocyte volume/mean corpuscular volume (MRV/MCV) ratio with conventional criteria (ANC and platelet count) in 22 allogeneic and 20 autologous BMT recipients. An abrupt increase in MRV/MCV ratio or a rise in MFI value were the earliest signs of erythropoietic recovery following allogeneic transplantation (63.6 and 22.8% of cases, respectively). In 13.6% of the cases, both parameters were observed simultaneously. All but three autologous transplant recipients showed changes in reticulocyte parameters earlier than ANC recovery. Granulocyte recovery and peripheral blood progenitor cells (PBPC) graft were predictive variables for RetAbs response in allogeneic transplant recipients. In the autologous group, predictive variables for RetAbs response were a high number of CD34+ infused cells and platelet recovery. An increase in the immature reticulocyte population is the earliest sign of haematopoietic recovery following BMT.