Accuracy of lymphocyte counts from UniCel DxH 800 in ß-thalassemia/HbE patients having various numbers of nucleated red blood cells.

BACKGROUND: The UniCel® DxH-800 is an automated cell counter widely used in laboratories. However, the effects of increased nucleated red blood cells (NRBCs) on the lymphocyte counts obtained using the UniCel DxH-800 have not been fully elucidated. OBJECTIVE: The study's objective was to compare lymphocyte counts obtained using the DxH-800 and those obtained using flow cytometry in various ranges of NRBCs. METHODS: This cross-sectional study analyzed 25 healthy volunteers and 69 ß-thalassemia/HbE patients. The numbers of lymphocytes were determined using a UniCel DxH-800 and a standard flow cytometer using counting beads. RESULTS: In healthy volunteers, regression analysis of the lymphocyte counts using the two approaches showed an r2 0.85 and a p < 0.0001, and a Bland-Altman plot showed mean bias of +264 cells/µL. In ß-thalassemia/HbE patients, regression analysis of the lymphocyte counts obtained using an automated cell counter and a flow cytometer showed an r2 of 0.06, a p = 0.028, and a Bland-Altman plot showed the mean bias of +1,509 cells/µL. In addition, a high degree of discrepancy in the lymphocyte counts was observed in ß-thalassemia/HbE patients who had NRBCs > 100,001 cells/µL. CONCLUSIONS: The present study demonstrated that the UniCel DxH-800 performed well in enumerating lymphocytes in specimens that contained various numbers of NRBCs. However, a high number of NRBCs may interfere with lymphocyte counts obtained using the counter.

Quantitation of phosphatidylserine-exposing platelets in platelet concentrate prepared in routine blood transfusion laboratory.

BACKGROUND: Phosphatidylserine (PS) plays important roles in platelets' pro-coagulant function. However, little is known about assessing this molecule in platelet concentrates (PCs) prepared for routine blood transfusion service. AIM: To quantitate the number of PS-exposing platelets in PCs prepared in a routine transfusion laboratory. METHODS: PC products were prepared according to routine laboratory procedure. The numbers of PS-exposing platelets in the PCs and in unprocessed whole blood were determined using flow cytometry. RESULTS: A cross-sectional study of 253 PCs found that they had significantly increased numbers of PS-exposing platelets compared to unprocessed whole blood (47,439 ±â€¯26,500 cells/µL; 5903‒166,156 cells/µL) vs. 30,058 ±â€¯12,958 cells/µL; 8,154-86,606 cells/µL). A heterogeneity study demonstrated that 6% and 2% of the measured PCs and of unprocessed donor whole blood, respectively, showed an increase in the number of PS-exposing platelets that was greater than 2 fold. CONCLUSIONS: The study suggested that the number PS-exposing platelets in PC prepared in a routine transfusion laboratory differs. However, assessment of the number of PS-exposing platelets in platelet products could be a valid measure to use in managing the quality of platelet processing in routine laboratories.

Replication and cytokine profiles of different subgenotypes of enterovirus 71 isolated from Thai patients in peripheral blood mononuclear cells.

Enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are common causative agents of mild and self-limiting symptoms of childhood hand, foot, and mouth disease (HFMD). However, some EV71-infected HFMD patients can develop severe neurological and/or fatal cardiopulmonary complications. In Thailand, HFMD associated with the EV71 subgenotypes C4a and B5 were reported to be associated with diverse outcomes. However, variations in enterovirus subgenotypes and virulence factors have not been fully elucidated; this study elucidated these variations in peripheral blood mononuclear cells (PBMCs) exposed to different subgenotypes of isolated enteroviruses for 24 and 48 h. Following infection, viral titers were determined by plaque assay. Infected cells and intracellular cytokines were quantified using flow cytometry, and multiplex assay was used to examine cytokine release. All isolated subgenotypes showed replication capability in PBMCs; specifically, the replication titer of EV71 C4a tended to be higher than titers of EV71 B5 and CA16. Additionally, the infectivity of EV71 B5 was higher in monocytes than in lymphocytes. Compared with EV71 B5, EV71 C4a and CA16 had greater ability to induce intra- and extracellular cytokine responses. These findings provide new insights into variations in cellular immune responses to different EV71 subgenotypes isolated from Thai patients, which should be considered for the development of vaccines and therapeutic agents.

Thalassemia trait and G6PD deficiency in Thai blood donors.

BACKGROUND: Thalassemia trait and G6PD deficiency are asymptomatic and volunteers with these variants are eligible for blood donation. AIMS: This study aimed to investigate prevalence and hematologic profiles of blood donors with thalassemia trait and G6PD deficiency and the influence of these abnormalities have on donor retention and blood component preparation. METHODS: Prospectively recruited blood donors were investigated for thalassemia and G6PD deficiency. Characteristic data, hematologic profiles, proportions of prepared blood components, donor return rate within 12 months and adverse reactions in patients receiving red cell transfusions were compared among thalassemia trait, G6PD deficiency, and normal donors. RESULTS: In Thai blood donors, thalassemia trait prevalence was 21.1% and G6PD deficiency prevalence based on G6PD activity was 7.7%. Blood donors with thalassemia trait had significantly lower hemoglobin, MCV, and MCH than blood donors without thalassemia trait (Hb 13.55 ± 1.00 vs. 13.96 ± 1.25 g/dL, MCV 76.70 ± 6.69 vs. 87.01 ± 5.10 fL, and MCH 25.06 ± 2.17 vs. 28.67 ± 1.91 pg, all respectively and all p < 0.01). However, the hematologic profiles of blood donors with G6PD deficiency were not significantly different from the hematologic profiles of blood donors with normal G6PD activity. No significant difference was observed among thalassemia trait, G6PD deficiency, and normal donors relative to donor retention and blood component preparation. CONCLUSION: The high prevalence of thalassemia trait and G6PD deficiency in Thai blood donors observed in this study does not adversely affect donor retention and blood component preparation.

Effects of donor age, donor sex, blood-component processing, and storage on cell-derived microparticle concentrations in routine blood-component preparation.

BACKGROUND: A number of factors cause increases in the number of cell-derived microparticles (MPs) in blood components. However, the overall effects of these factors on the concentration of MPs during routine blood-component preparation have not fully been elucidated. AIM: To evaluate the effects of donor age, donor sex, blood-component preparation, and storage on MP concentrations. METHODS: Flow cytometry was used to quantitate the number of whole blood-derived MPs. RESULTS: The total MP concentration was similar in male and female donors (26,044 ± 1254 particles/µL vs. 27,696 ± 1584 particles/µL). The total MP concentration did not differ significantly among the different age groups: 18-30 years (28,730 ± 1600 particles/µL), 31-40 years (24,972 ± 5947 particles/µL), and 41-58 years (25,195 ± 1727 particles/µL). However, the total number of MPs in fresh plasma (152,110 ± 46,716 particles/µL) was significantly higher (p < 0.05) than that in unprocessed whole blood (26,752 ± 985 particles/µL), fresh packed red blood cells (PRBCs) (28,574 ± 1028 particles/µL), and platelet concentrate (PC) (33,072 ± 1858 particles/µL). Furthermore, the total numbers of MPs in stored PRBCs and fresh-frozen plasma (FFP) were significantly higher (p < 0.05) than those in fresh PRBCs and fresh plasma, respectively. CONCLUSIONS: The study suggests that donor factors, blood-component processing and storage contribute to the MP concentration in routine blood-product preparation. The findings can improve quality control and management of blood-product manufacturing in routine transfusion laboratories.

Normalized levels of red blood cells expressing phosphatidylserine, their microparticles, and activated platelets in young patients with ß-thalassemia following bone marrow transplantation.

Bone marrow transplantation (BMT) serves as the only curative treatment for patients with ß-thalassemia major; however, hemostatic changes have been observed in these BMT patients. Aggregability of thalassemic red blood cells (RBCs) and increased red blood cell-derived microparticles (RMPs) expressing phosphatidylserine (PS) are thought to participate in thromboembolic events by initially triggering platelet activation. To our knowledge, there has been no report providing quantitation of these circulating PS-expressing RBCs and RMPs in young ß-thalassemia patients after BMT. Whole blood from each subject was fluorescently labeled to detect RBC markers (CD235a) and annexin-V together with the known number TruCount™ beads. PS-expressing RBCs, RMPs, and activated platelets were identified by flow cytometry. In our randomized study, we found the decreased levels of three aforementioned factors compared to levels in patients receiving regular blood transfusion (RT). This study showed that BMT in ß-thalassemia patients decreases the levels of circulating PS-expressing RBCs, their MPs, and procoagulant platelets when compared to patients who received RT. Normalized levels of these coagulation markers may provide the supportive evidence of the effectiveness of BMT for curing thalassemia.

Microparticles from splenectomized ß-thalassemia/HbE patients play roles on procoagulant activities with thrombotic potential.

Thromboembolic events including cerebral thrombosis, deep vein thrombosis, and pulmonary embolism are major complications in ß-thalassemia. Damaged red blood cells and chronic platelet activation in splenectomized ß-thalassemia/HbE patients were associated with increased microparticles (MPs) releases into blood circulation. MPs are small membrane vesicles, which play important roles on coagulation. However, the role of MP in thalassemia is poorly understood. In this study, the effects of splenectomized-MPs on platelet activation and aggregation were investigated. The results showed that isolated MPs from fresh platelet-free plasma of patients and normal subjects directly induce platelet activation, platelet aggregation, and platelet-neutrophil aggregation in a dose-dependent manner. Interestingly, MPs obtained from splenectomized patients are more efficient in induction of platelet activation (P-selectin+) when compared to MPs from normal subjects (P < 0.05), tenfold lower than pathophysiological level, at 1:0.1 platelet MP ratio. Co-incubation of splenectomized-MPs with either normal-, non-splenectomized- or splenectomized-platelets at 1:10 platelet MP ratio increased platelet activation up to 5.1 ± 2.2, 5.6 ± 3.7, and 9.5 ± 3.0%, respectively, when normalized with individual baseline. These findings suggest that splenectomized patients were proned to be activated by MPs, and splenectomized-MPs could play an important role on chronic platelet activation and aggregation, leading to thrombus formation in ß-thalassemia/HbE patients.

Flow rate calibration to determine cell-derived microparticles and homogeneity of blood components.

BACKGROUND: Cell-derived microparticles (MPs) are currently of great interest to screening transfusion donors and blood components. However, the current approach to counting MPs is not affordable for routine laboratory use due to its high cost. AIM: The current study aimed to investigate the potential use of flow-rate calibration for counting MPs in whole blood, packed red blood cells (PRBCs), and platelet concentrates (PCs). METHODS: The accuracy of flow-rate calibration was investigated by comparing the platelet counts of an automated counter and a flow-rate calibrator. The concentration of MPs and their origins in whole blood (n=100), PRBCs (n=100), and PCs (n=92) were determined using a FACSCalibur. The MPs' fold-changes were calculated to assess the homogeneity of the blood components. RESULTS: Comparing the platelet counts conducted by automated counting and flow-rate calibration showed an r2 of 0.6 (y=0.69x+97,620). The CVs of the within-run and between-run variations of flow-rate calibration were 8.2% and 12.1%, respectively. The Bland-Altman plot showed a mean bias of -31,142platelets/µl. MP enumeration revealed both the difference in MP levels and their origins in whole blood, PRBCs, and PCs. Screening the blood components demonstrated high heterogeneity of the MP levels in PCs when compared to whole blood and PRBCs. CONCLUSIONS: The results of the present study suggest the accuracy and precision of flow-rate calibration for enumerating MPs. This flow-rate approach is affordable for assessing the homogeneity of MPs in blood components in routine laboratory practice.

Differences in levels of platelet-derived microparticles in platelet components prepared using the platelet rich plasma, buffy coat, and apheresis procedures.

BACKGROUND: There has been an increased interest in platelet-derived microparticles (PMPs) in transfusion medicine. Little is known about PMP status during the preparation of platelet concentrates for transfusion. AIM: The aim of this study is to compare the PMP levels in platelet components prepared using the buffy coat (BC), platelet-rich plasma platelet concentrate (PRP-PC), and apheresis (AP) processes. METHODS: Platelet components were prepared using the PRP-PC and BC processes. Apheresis platelets were prepared using the Trima Accel and Amicus instruments. The samples were incubated with annexin A5-FITC, CD41-PE, and CD62P-APC. At day 1 after processing, the PMPs and activated platelets were determined using flow cytometry. RESULTS: Both the percentage and number of PMPs were higher in platelet components prepared using the Amicus instrument (2.6±1.8, 32802±19036 particles/µL) than in platelet components prepared using the Trima Accel instrument (0.5±0.4, 7568±5298 particles/µL), BC (1.2±0.6, 12,920±6426 particles/µL), and PRP-PC (0.9±0.6, 10731±5514 particles/µL). Both the percentage and number of activated platelets were higher in platelet components prepared using the Amicus instrument (33.2±13.9, 427553±196965 cells/µL) than in platelet components prepared using the Trima Accel instrument (16.2±6.1, 211209±87706 cells/µL), BC (12.9±3.2, 140624±41003 cells/µL), and PRP-PC (21.1±6.3, 265210±86257 cells/µL). CONCLUSIONS: The study suggests high variability of PMPs and activated platelets in platelet components prepared using different processes. This result may be important in validating the instruments involved in platelet blood collection and processing.

Phenotypic characterization of circulating CD4/CD8 T-lymphocytes in ß-thalassemia patients.

BACKGROUND: Infection is one of the most common causes of death in ß-thalassemia patients. This may be due in part to an underlying immunological abnormality. During the past decade, a subset of CD3+ T cells that express both CD4+CD8+ (DP) T-cells were discovered and have been described in several pathological conditions. However, phenotypic characterization of this unique T-lymphocyte subset in patients with ß-thalassemia has not yet been investigated. METHODS: Flow cytometry was used to determine the frequency of such CD4+CD8+(DP) cells in concert with frequencies of CD4+, CD8+, NKT cells and γδ-TCR T-lymphocytes in the peripheral blood of ß-thalassemia/HbE patients. The frequencies of these lymphocyte subsets were compared with those in blood samples from healthy volunteers. RESULTS: The results showed that the frequency of lymphocytes was significantly increased in splenectomized ß-thalassemia/HbE patients but the frequencies of CD3+, CD4+ and CD8+ T-lymphocytes were not significantly different among the studied groups. However, analysis of unconventional T-lymphocytes revealed a significant increase in the frequency of CD4-CD8- in splenectomized ß-thalassemia/HbE patients. The frequencies of CD4-CD8dim and CD4+CD8+ in ß-thalassemia/HbE patients were similar to the controls. Further classification of the CD4+CD8+ cells revealed that ß-thalassemia/HbE patient expressed significantly high levels of CD4brightCD8dim, with a marked increase found in non-splenectomized patients. Furthermore, significant increases in the frequency of γδ-TCR and NKT cells were also demonstrated in these splenectomized ß-thalassemia/HbE patients. CONCLUSION: Our findings show the alteration of unconventional T-lymphocyte subsets in ß-thalassemia/HbE patients, which may be responsible or may reflect the impaired immune response in ß-thalssemia disease.

Blood Donors with Thalassemic Trait, Glucose-6-Phosphate Dehydrogenase Deficiency Trait, and Sickle Cell Trait and Their Blood Products: Current Status and Future Perspective.

The use of blood products for different medical purposes has increased in recent years. To meet increasing demand, some blood centers allow volunteer donors with thalassemic trait, glucose-6-phosphate dehydrogenase deficiency (G6PD) trait, and sickle cell trait (SCT) to donate blood if their hemoglobin values fall within acceptable ranges and show no signs of hemolysis. Currently, there are no standard guidelines or policies regarding the use or management of blood products obtained from these donors. However, in recent years, there has been advanced research on eligible donors who have these underlying conditions. In this review, we summarize the current knowledge from in vitro and in vivo studies regarding donor characteristics, changes in physical and biochemical parameters in blood products during processing and storage, and posttransfusion efficacy of blood products. In addition, we discuss some unresolved issues concerning blood products from thalassemic trait, G6PD-deficiency trait, and SCT donors.

Diagnostic Performance of 10 Mathematical Formulae for Identifying Blood Donors with Thalassemia Trait.

OBJECTIVE: To compare the diagnostic performance of 10 mathematical formulae for identifying thalassemia trait in blood donors. METHODS: Compete blood counts were conducted on peripheral blood specimens using the UniCel DxH 800 hematology analyzer. Receiver operating characteristic curves were used to evaluate the diagnostic performance of each mathematical formula. RESULTS: In the 66 donors with thalassemia and 288 subjects with no thalassemia analyzed, donors with thalassemia trait had lower values for mean corpuscular volume and mean corpuscular hemoglobin than subjects without thalassemia donors (77 fL vs 86 fL [P < .001]; 25 pg vs 28 pg [P < .001]). The formula developed by Shine and Lal in 1977 showed the highest area under the curve value, namely, 0.9. At the cutoff value of <1812, this formula had maximum specificity of 82.35% and sensitivity of 89.58%. CONCLUSIONS: Our data indicate that the Shine and Lal formula has remarkable diagnostic performance in identifying donors with underlying thalassemia trait.

Thrombopoietin-independent generation of platelet-like particles from megakaryoblastic cells.

The use of megakaryoblastic leukemia MEG-01 cells can help reveal the mechanisms of thrombopoiesis. However, conventional in vitro activation of platelet release from MEG-01 cells requires thrombopoietin, which is costly. Here, we aim to develop a more straightforward and affordable method. Synchronization of the MEG-01 cells was initially performed using serum-free culture, followed by spontaneous cell differentiation in the presence of serum. Different stages of megakaryoblast differentiation were classified based on cell morphology, DNA content, and cell cycle. The MEG-01 cells released platelet-like particles at a level comparable to that of the thrombopoietin-activated MEG-01 cells. The platelet-like particles were distinguishable from PLP-derived extracellular vesicles and could express P-selectin following ADP activation. Importantly, the platelet-like particles induced fibrin clotting in vitro using platelet-poor plasma. Therefore, this thrombopoietin-independent cell synchronization method is an effective and straightforward method for studying megakaryopoiesis and thrombopoiesis.

The use of acridine orange and glutaraldehyde-fixed chicken red blood cells for absolute counting of residual white blood cells in leuco-depleted packed red blood cells.

BACKGROUND: We have previously developed an affordable flow cytometric method for absolute cell count using glutaraldehyde-fixed chicken red blood cells. However, its use is limited to CD4+ T cells. In the current investigation, we studied the potential use of glutaraldehyde-fixed chicken RBCs to determine the number of residual white blood cells (rWBCs) in WBC-reduced blood component. METHODS: Acridine orange (AO) was used to identify leucocytes in serial diluted blood samples ranging from 0.65 to 1,000 cells/microL. The absolute number of AO stained leucocytes were determined by using a known number of glutaraldehyde-fixed chicken RBCs on flow cytometer. The results were compared with the expected value and the absolute count determined by BD Leucocount (Becton Dickinson Bioscience). In addition, the stability of AO stained leucocytes and sample stability at various time points were measured. Reproducibility of the assay method was also addressed. RESULTS: There was a good correlation in the number of leucocytes between our new method and the expected numbers from serially diluted blood samples (r2 = 0.99, y = 1.04x + 0.50, p < 0.001). Furthermore, absolute leucocyte counts determined by the new method correlated well with those obtained from BD Leucocount (r2 = 0.99, y = 1.31 x - 6.37, p < 0.001). FL-1 intensity and the absolute number of AO stained leucocytes were stable for at least 24 hours after staining. Samples stored at 4 degrees C were stable for 48 hours and CV of the assay was at an acceptable level. CONCLUSION: This flow cytometric method for absolute leucocyte counts using AO and glutaraldehyde-fixed chicken RBCs is a simple, rapid, reliable and inexpensive method for routine monitoring of low levels of leucocytes in blood products.

Storage Duration and Red Blood Cell-Derived Microparticles in Packed Red Blood Cells Obtained from Donors with Thalassemia.

OBJECTIVE: To address the effects of storage duration on red blood cell (RBC)-derived microparticles (RMPs) in packed RBCs from donors who have thalassemia. MATERIALS AND METHODS: Packed RBCs were prepared according to laboratory routine. The quantity of RMPs was determined using FACSCalibur and counting beads. RESULTS: Across durations of storage, the packed RBCs from donors with thalassemia (n = 28) and healthy volunteers (n = 104) showed average RMPs to be 47,426 (10,139‒127,785) particles/µL vs 49,021 (13,033‒126,749) particles/µL, respectively (P = .63). The peak RMP levels in donors with thalassemia and healthy volunteers, respectively, were shown in products from storage days 34 and 38. Both groups showed a trend toward a positive association between RMP concentration and the duration of storage in packed RBC bags stored under blood bank conditions. CONCLUSION: Our results suggest that storage-induced RMP release has similar effects in stored packed RBCs obtained from both donors with thalassemia and healthy volunteers.

Urinary red blood cell-derived microparticles and phosphatidylserine-exposing red blood cells in glomerular and non-glomerular hematuria patients.

BACKGROUND: Distinguishing glomerular hematuria (GH) from non-glomerular hematuria (NGH) is important for treating the cause of hematuria. We aimed to determine red blood cell-derived microparticles (RMPs) and phosphatidylserine (PS)-exposing red blood cells (RBCs) and evaluate their use for diagnosing GH and NGH patients. METHODS: All patients received a physical assessment and urological examination. Dysmorphic RBCs (dRBCs) and acanthocytes were examined using a light microscope. The urinary RMPs and PS-exposing RBCs were determined using flow cytometry. RESULTS: The ratio of RMPs to RBCs was higher in GH patients (n = 29) than in NGH patients (n = 29) (1.06 vs. 0.18). The value of the sum of the PS-exposing RBCs plus RMPs divided by the number of RBCs was higher in GH patients than in NGH patients (48.3% vs. 19.4%). The percentage of RBCs was higher in GH patients than in NGH patients (54.5% vs. 21.8%). Similarly, both the percentages of acanthocytes and of non-acanthocytes were higher in GH patients than in NGH patients (29% vs. 7.7% and 25.4% vs. 14.2%, respectively). The ROC-AUC of the number of PS-exposing RBCs plus RMPs divided by the number of RBCs was 0.9 (95% CI, 0.82-0.97), and the RMPs:RBCs ratio was 0.88 (95% CI, 0.79-0.98). The ROC-AUCs of the dRBCs and acanthocytes were 0.85 (95% CI, 0.78-0.95) and 0.88 (95% CI, 0.8-0.97), respectively. CONCLUSIONS: Patients with GH have higher numbers of urinary RMPs and PS-exposing RBCs. These parameters have the potential to be predictive tools for classifying GH in the future.

Flow cytometric CD4 enumeration of four different HIV-infected blood samples at the cost of one monoclonal antibody reagent.

BACKGROUND: The frequency and absolute number of CD4+ T-lymphocytes continue to be one of the major clinical markers for management of HIV/AIDS. The present standard dual-platform (DP) three-color and two-color PanLeucogating flow cytometric (FCM) methods for most developing countries are either expensive if manufacturers' monoclonal antibody reagents are used or limited due to an insufficient supply of generic reagents. Clearly, more affordable FCM methods are needed. OBJECTIVE: To develop a novel DP FCM method using biotin-streptavidin-fluorochrome labeling in combination with the two standard DP methods for 4 different white blood cells (WBC) using only one monoclonal antibody reagent. METHODS: The percentage of CD4+ T-lymphocytes in 116 HIV-infected blood samples was determined using our new method. Results were compared with the two standard methods. Correlation and agreement of the pair method were determined using linear regression, Bland-Altman and percent similarity analysis. RESULTS: Our study showed that percentage of CD4+ T-lymphocyte values obtained from the new method correlated highly with the standard three-color and the two-color methods (r2 = 0.95 {n=52} and 0.97 {n=64}). The mean bias and percent similarity for the new method compared with the two standard methods were -0.53% (limit of agreement {LOA}:-5.22% to +4.16% with percent similarity of 99.28; and -0.22% with LOA of -3.42% to +2.98%, the percent similarity of 98.15, respectively. CONCLUSIONS: Our FCM method using biotin to label 4 different WBC samples followed by streptavidin staining is reliable for determination of CD4+ T-lymphocytes. Such an approach will significantly reduce the cost for monitoring HIV-infected patients in resource-limited settings.

Effects of Cell-Derived Microparticles on Immune Cells and Potential Implications in Clinical Medicine.

In the past few years, interest has increased in cell-derived microparticles (MPs), which are defined by their size of from 0.1 to 1 µm, and can be derived from various cell types, including endothelial cells, leukocytes, red blood cells (RBCs), and platelets. These MPs carry negatively charged phosphatidylserine (PS) on their surfaces and proteins packaged from numerous cellular components. MPs that have been shed by the body can play important roles in the pathophysiology of diseases and can affect various biological systems. Among these systems, the immune components have been shown to be modulated by MPs. Therefore, understanding the roles of MPs in the immune system is crucial to developing alternative therapeutic treatments for diseases. This review describes the effects of MPs on various immune cells and provides plausible potential applications of the immune-modulating properties of MPs in clinical medicine.

Cell-Derived Microparticles in Blood Products from Blood Donors Deficient in Glucose-6-Phosphate Dehydrogenase.

OBJECTIVE: To quantitate the microparticles (MPs) in whole blood and blood products obtained from blood donors who are deficient in glucose-6-phosphate dehydrogenase (G6PD). METHODS: The current study analyzed whole blood and blood components prepared from 49 blood donors with G6PD deficiencies and 98 with G6PD-normal results. Packed red blood cells (PRBCs), platelet concentrate (PC), and plasma were prepared according to transfusion laboratory procedures. MP concentrations were determined using a flow cytometer. RESULTS: Blood components prepared from donors with G6PD deficiency were characterized by higher red blood cell-derived MP (RMP) concentration in PRBCs (25,526 vs 18,738 particles/µL) but lower concentrations of platelet-derived MPs (PMPs; in whole blood and PC), leukocyte-derived MPs (LMP; in whole blood and plasma) and total MP (in PC), compared with those from donors with G6PD-normal test results. CONCLUSIONS: These results suggest that differences in G6PD status may account for variation in RMP levels during processing.

Cell-Derived Microparticles in Blood Products from Thalassemic Blood Donors.

OBJECTIVE: To determine the number of cell-derived microparticles (MPs) in blood products obtained from donors who have thalassemia. METHODS: Packed red blood cells (PRBCs), plasma, and platelet concentrate (PC) were prepared according to routine procedures. We used flow cytometry to quantitate the concentration of MPs. RESULTS: The results of a comparison of MP levels in unprocessed whole blood showed that the concentration of all MPs in the donors without thalassemia trait (n = 255) was higher than in donors with thalassemia trait (n = 70). After processing, increased concentrations of MPs were documented in both groups. Among the blood components, PRBC showed higher platelet-derived MP concentrations in donors with thalassemia than in donors without thalassemia. However, PC showed higher concentrations of total MPs in donors without thalassemia than in donors with that condition. CONCLUSIONS: Our results suggest little influence of thalassemia-trait status on changes in MP concentrations in blood components.