A variety of apheresis devices are now available on the market for plateletapheresis. We compared two apheresis instruments (Fenwal Amicus and Fresenius COM.TEC) with regard to processing time, platelet (PLT) yield and efficiency, and white blood cell (WBC) content.
Material and Methods
Donors undergoing plateletpheresis were randomly separated into two groups (either the Amicus or the COM.TEC cell separator).
In the pre-apheresis setting, 32 plateletpheresis procedures performed with each instrument revealed no significant differences in donors’ sex, age, weight, height and total blood volume between the two groups. However, the pre-apheresis PLT count was higher with the COM.TEC than with the Amicus (198 × 103/μl vs. 223 × 103/μl; p = 0.035). The blood volume processed to reach a target PLT yield of ≥3.3 × 1011 was higher in the COM.TEC compared to the Amicus (3,481 vs. 2,850 ml; p < 0.001). The median separation time was also significantly longer in the COM.TEC than in the Amicus (61 vs. 44 min; p < 0.001). 91 and 88% of the PLT products collected with the Amicus and the COM.TEC, respectively, had a PLT count of >3.3 × 1011 (p = 0.325). All products obtained with both instruments had WBC counts lower than 5 ↔ 106, as required. There was no statistical difference with regard to collection efficiency between the devices (55 ± 15 vs. 57 ± 15%; p = 0.477). However, the collection rate was significantly higher with the Amicus compared to the COM.TEC instrument (0.077 ± 0.012 × 1011 vs. 0.057 ± 0.008 × 1011 PLT/min; p < 0.001).
Both instruments collected platelets efficiently. Additionally, consistent leukoreduction was obtained with both instruments; however, compared with the COM.TEC instrument, the Amicus reached the PLT target yield more quickly.
Plateletpheresis; Apheresis; Amicus; COM.TEC; Cell separator
Soluble mediators in platelet concentrates (PCs) released from contaminating white blood cells (WBCs) and platelets (PLTs) themselves are supposed to promote allergic and non-hemolytic febrile transfusion reactions in the recipient. Pathogen reduction technologies (PRTs) prevent replication and proliferation of pathogens as well as of WBCs, and may reduce cytokine accumulation in PCs during storage and prevent adverse events after PLT transfusion. On the other hand, such treatments may also lead to increased cytokine production by stimulation of WBCs or PLTs due to the photochemical or photodynamical process itself.
Material and Methods
12 triple-dose PLT apheresis collections were leukoreduced by the process-controlled leukoreduction system of the Trima Accel machine and split into 3 units undergoing Mirasol-PRT treatment (M) or gamma irradiation (X) or remaining untreated (C). During storage for up to 7 days, PLT activation, WBC-derived Th-1/2, and inflammatory as well as PLT-derived cytokines were measured by cytometric bead array and enzymelinked immunosorbent assay, respectively.
Independent of treatment, all PLT products exhibited low levels of WBC-associated cytokines near or below assay detection limits. WBC-associated cytokines were not elevated by Mirasol-PRT treatment. PLT-derived cytokines were detected at higher levels and increased significantly during storage in all units. Most likely due to higher PLT activation, M units showed significantly higher levels of PLT-derived cytokines compared to untreated and gamma-irradiated units on day 5 of storage.
In all PCs, PLTs themselves were the main source of cytokine release. Mirasol-PRT treatment was associated with a significantly increased PLT activation and accumulation of PLT-derived cytokines during storage, without affecting WBC-derived cytokines relative to controls.
Pathogen reduction; Mirasol-PRT; Ccytokines; Transfusion reaction
During haemodialysis (HD), platelets (PLTs) are activated and release granule contents. As HD treatment occurs three times a week, it has been demonstrated that PLTs are exhausted due to the repetitive character of the treatment. To identify PLT depletion morphologically, PLT evaluation was performed by light microscopy and electron microscopy (EM) in a chronic HD subject and a healthy reference subject. Blood samples were taken before the start of HD treatment for measurement of PLT count, PLT volume and size parameters. Blood smears were screened by light microscopy for qualitative evaluation of PLT granule containing cytoplasm, as indicated by its staining density. Morphological PLT parameters of surface area and size of dense bodies were assessed by EM. Data were compared with results of a group of 20 chronic HD subjects and a group of 20 healthy reference subjects. With respect to the percentage of PLTs with appropriate staining density (>75%), light microscopic evaluation showed that this value (9%) was within the range of a group of chronic HD subjects, but considerably below the reference range (70%). EM evaluation revealed an average PLT surface area and dense bodies area of respectively 42% and 31%, if the healthy reference subject was set on 100%. PLTs from a chronic HD subject are considerably smaller and substantially less granular than PLTs from a healthy reference subject. These findings support the hypothesis of PLT depletion in chronic HD subjects due to frequent PLT activation and/or increased urea concentrations.
electron microscopy; platelet activation; platelet degranulation; haemodialysis.
We compare the actual with the potential donor exposure and possible infection rates in the Hanover Medical School (MHH) platelet (PLT) transfusion recipients if the current MHH standard of apheresis PLT concentrate (A-PC) supply would be replaced by a pooled PLT concentrate (P-PC) transfusion regimen.
Donors, Patients, and Methods
The electronic records of the MHH Institute of Transfusion Medicine and the MHH Department of Medical Controlling were evaluated to assess the development of PLT needs and supply at MHH from 2003–2006. For 2006, we evaluated all PLT transfusion recipients with respect to their overall transfusion needs, classified them for low and high PLT transfusion needs, and related them to the diagnostic groups that underlie their PLT demands. We assumed a P-PC preparation procedure using 4 whole blood-derived buffy coats for all calculations for potential donor exposure. To predict the possible infection rates of an unrecognized viral infection with low prevalence in the general population to A-PC or to P-PC recipients and the influence of neutralizing agent specific antibodies (NAB), we established a mathematical contamination/infection model based on the current PLT transfusion mode and data about GBV-C virus infection among Hanover blood donors.
From 2003 to 2006, the 1,300–1,400 persons comprising MHH apheresis donor pool covered a 36% increase in PC transfusions. The exclusive use of P-PCs instead of A-PC would require a total of 36,240–49,276 whole blood donations to meet MHH demands, corresponding to a more than 1 log step increase in donor exposure. For individual hematological patients, the change to P-PCs would imply an 80–125%, for individual surgical patients a 40–50% higher donor exposure. Our infection model revealed an approximately 4 times higher infection.
A change to P-PC would imply a more than one log step higher donor exposure, and an unrecognized infection with a prevalence around 1% leads to an up to 4 times higher infection rate. A general change in the PC transfusion policy that favors P-PCs is dangerous and must be avoided.
Donor exposure; Apheresis platelet concentrates; Pooled platelet concentrates; Infection rates from apheresis platelet concentrates; Infection rates from pooled platelet concentrates
In vitro function of stored platelet (PLT) con-centrates was analyzed after applying two different techniques of pathogen reduction technology (PRT) treatment, which could increase cellular injury during processing and storage.
Nine triple-dose PLT apheresis donations were split into 27 single units designated to riboflavin-UVB (M) or psoralen-UVA (I) treatment or remained untreated (C). Throughout 8 days of storage, samples were analyzed for annexin V release, the mitochondrial transmembrane potential (Δψ) and some classical markers of PLT quality (pH, LDH release, hypotonic shock response (HSR)).
PLT count and LDH release of all units maintained initial ranges. All units exhibited a decrease in pH and HSR and an increase in annexin V release and Δψ disruption. Notably, throughout the entire storage period, annexin V release re-mained lowest in M units. Throughout 7 days of storage, M units remained comparable to C units (p > 0.05), whereas inferior values were observed with I units. Here, differences to C units reached significance by day 1 (pH: p < 0.0001), day 5 (annexin V release: p < 0.014), and day 7 (HSR, Δψ: p ≤ 0.003). After PRT treatment, annexin V release and Δψ disruption were significantly (p < 0.001) correlated with pH and HSR.
During storage, all units showed a de-crease in HSR and an increase in acidity, annexin V release and Δψ disruption. While M units remained comparable to C units, I units demonstrated significantly inferior values during terminal storage. This could have resulted from differences in PRT treatment or simply be due to differences in storage media and should be analyzed for clinical relevance in future investigations.
Pathogen reduction technology; Platelet in vitro function; Endogenous annexin V; Transmembrane mitochondrial potential; INTERCEPT BLOOD SYSTEM; MIRASOL-PRT
Background and Objectives
Platelets during storage undergo diverse alterations collectively known as the platelet storage lesion, including metabolic, morphological, functional and structural changes. Some changes correlate with activation of p38 mitogen activated protein kinase (p38 MAPK). Another MAPK, extracellular signal-related kinase (ERK), is involved in PLT activation. The aim of this study was to compare the properties of platelets stored in plasma in the presence or absence of p38 and ERK MAPK inhibitors.
Materials and Methods
A single Trima apheresis platelet unit (n = 12) was aliquoted into five CLX storage bags. Two aliquots were continuously agitated with or without MAPK inhibitors. Two aliquots were subjected to 48 hours of interruption of agitation with or without MAPK inhibitors. One aliquot contained the same amount of solvent vehicle used to deliver the inhibitor. Platelets were stored at 20–24°C for 7 days and sampled on Days 1, 4, and 7 for 18 in vitro parameters.
Inhibition of p38 MAPK by VX-702 leads to better maintenance of all platelet in vitro storage parameters including platelet mitochondrial function. Accelerated by interruption of agitation, the platelet storage lesion of units stored with VX-702 was diminished to that of platelets stored with continuous agitation. Inhibition of ERK MAPK did not ameliorate decrements in any in vitro platelet properties.
Signaling through p38 MAPK, but not ERK, is associated with platelet deterioration during storage.
Lymphocyte cultures grown from liver allograft biopsies were shown to exhibit alloreactivity towards donor cells as measured by primed lymphocyte testing (PLT). The PLT specificity was determined in assays using HLA typed panel cells and/or by inhibition testing with HLA specific monoclonal antibodies. Certain cultures exhibited PLT specificity towards class I HLA antigens of the donor, whereas others were specific for class II HLA antigens or recognized mixtures of class I and II antigens. These PLT specificity patterns were compared with clinical, histological and laboratory findings on the liver transplant patients at the time of the biopsy. Biopsies yielding class I specific PLT cells were taken generally during the earlier posttransplant period, whereas class II specific cells were grown from later biopsies. There was no significant correlation of the PLT specificity towards class I vs II antigens with the levels of total or direct bilirubin, serum glutamate oxaloacetic transaminase (SGOT), and serum glutamate pyruvate transaminase (SGPT), although a trend towards higher values was noted for biopsies presenting with a class II specific infiltrate. However, the levels of gamma glutamyl transpeptidase (GGTP) and alkaline phosphatase (AP) were significantly increased when biopsies yielded class II specific rather than class I specific PLT cells. Biopsy histology showed more damage to bile duct epithelium in association with class II PLT specificity whereas intense but often reversible infiltrates were found in biopsies yielding class I specific cells. The elevated GGTP and AP levels are probably related to the interaction of class II specific T cells with bile duct epithelium, which has been shown to express induced class II HLA antigens on their cell surface.
T-lymphocytes; liver transplants; donor HLA alloreactivity; liver function tests; histopathology; bile duct damage
Transfusion-related acute lung injury (TRALI) mitigation strategies include the deferral of female donors from apheresis platelet (PLT) donations and the distribution of plasma for transfusion from male donors only. We studied the implications of these policies in terms of component loss at six blood centers in the United States.
STUDY DESIGN AND METHODS
We collected data from allogeneic blood donors making whole blood and blood component donations during calendar years 2006 through 2008. We analyzed the distribution of donations in terms of the sex, transfusion and pregnancy histories, and blood type.
A TRALI mitigation policy that would not allow plasma from female whole blood donors to be prepared into transfusable plasma components would result in nearly a 50% reduction in the units of whole blood available for plasma manufacturing and would decrease the number of type AB plasma units that could be made from whole blood donations by the same amount. Deferral of all female apheresis PLT donors, all female apheresis PLT donors with histories of prior pregnancies, or all female apheresis PLT donors with histories of prior pregnancies and positive screening test results for antibodies to human leukocyte antigens (HLAs) will result in a loss of 37.1, 22.5, and 5.4% of all apheresis PLT donations, respectively.
A TRALI mitigation policy that only defers female apheresis PLT donors with previous pregnancies and HLAs would result in an approximately 5% decrease in the inventory of apheresis PLTs, but would eliminate a large proportion of components that are associated with TRALI.
Rapidly available and accurate platelet counts play an important role in the evaluation of haemorrhagic status and in assessing the need for platelet transfusions. We, therefore, evaluated platelet counting performance of haematology analysers using optical, impedance and immunological methods in thrombocytopenic patients.
Materials and Methods
We considered 99 patients with a platelet (plt) count under 50x109 plt/L. We compared the platelet counts obtained using ADVIA 2120 (optical method), Cell-Dyn Sapphire (optical, impedance and immunological methods with CD61) and a reference, double staining (CD41+CD61) immunological method.
The platelet counts of all the considered methods showed good correlation with those of the reference method, despite an overestimation in platelet quantification. The degree of inaccuracy was greater for platelet counts under 20 x109 plt/L.
Clinicians who use platelet thresholds below 20 x109 plt/L for making clinical decisions must be aware of the limitations in precision and accuracy of cell counters at this level of platelet count. Inaccurate counts of low platelet numbers could create problems if attempts are made to reduce the threshold below 20x109 plt/L.
Platelet count; Accuracy; Thrombocytopenia; Method's correlation
AIM: To establish a simple model consisting of the routine laboratory variables to predict both minimal fibrosis and cirrhosis in chronic hepatitis B virus (HBV)-infected patients.
METHODS: We retrospectively investigated 114 chronic HBV-infected patients who underwent liver biopsy in two different hospitals. Thirteen parameters were analyzed by step-wise regression analysis and correlation analysis. A new fibrosis index [globulin/platelet (GP) model] was developed, including globulin (GLOB) and platelet count (PLT). GP model = GLOB (g/mL) × 100/PLT (× 109/L). We evaluated the receiver operating characteristics analysis used to predict minimal fibrosis and compared six other available models.
RESULTS: Thirteen clinical biochemical and hematological variables [sex, age, PLT, alanine aminotransferase, aspartate aminotransferase (AST), albumin, GLOB, total bilirubin (T.bil), direct bilirubin (D.bil), glutamyltransferase, alkaline phosphatase, HBV DNA and prothrombin time (PT)] were analyzed according to three stages of liver fibrosis (F0-F1, F2-F3 and F4). Bivariate Spearman’s rank correlation analysis showed that six variables, including age, PLT, T.bil, D.bil, GLOB and PT, were correlated with the three fibrosis stages (FS). Correlation coefficients were 0.23, -0.412, 0.208, 0.220, 0.314 and 0.212; and P value was 0.014, < 0.001, 0.026, 0.018, 0.001 and 0.024, respectively. Univariate analysis revealed that only PLT and GLOB were significantly different in the three FS (PLT: F = 11.772, P < 0.001; GLOB: F = 6.612, P = 0.002). Step-wise multiple regression analysis showed that PLT and GLOB were also independently correlated with FS (R2 = 0.237). By Spearman’s rank correlation analysis, GP model was significantly correlated with the three FS (r = 0.466, P < 0.001). The median values in F0-F1, F2-F3 and F4 were 1.461, 1.720 and 2.634. Compared with the six available models (fibrosis index, AST-platelet ratio, FIB-4, fibrosis-cirrhosis index and age-AST model and age-PLT ratio), GP model showed a highest correlation coefficient. The sensitivity and positive predictive value at a cutoff value < 1.68 for predicting minimal fibrosis F0-F1 were 72.4% and 71.2%, respectively. The specificity and negative predictive value at a cutoff value < 2.53 for the prediction of cirrhosis were 84.5% and 96.7%. The area under the curve (AUC) of GP model for predicting minimal fibrosis and cirrhosis was 0.762 [95% confidence interval (CI): 0.676-0.848] and 0.781 (95% CI: 0.638-0.924). Although the differences were not statistically significant between GP model and the other models (P all > 0.05), the AUC of GP model was the largest among the seven models.
CONCLUSION: By establishing a simple model using available laboratory variables, chronic HBV-infected patients with minimal fibrosis and cirrhosis can be diagnosed accurately, and the clinical application of this model may reduce the need for liver biopsy in HBV-infected patients.
Globulin; Platelet; Globulin/platelet model; Liver fibrosis; Noninvasive fibrosis biomarker; Chronic hepatitis B virus
During haemodialysis (HD) treatment, increase of platelet (PLT) activation and induction of procoagulant activity is demonstrated. Although the role of the endothelium and its direct interaction with coagulation and homeostasis is known, it is not elucidated how PLT activation markers and activation of coagulation coincide with markers of endothelial integrity during HD treatment. In the present study uraemia and HD induced changes, with particular emphasis on PLT granules depletion, activation of coagulation and endothelial integrity were investigated.
To detect depletion of PLT granules, peripheral blood slide smears were screened by light microscopy for qualitative evaluation of PLT granule containing cytoplasm, as indicated by its granules staining density. Activation of coagulation was investigated by establishement of thrombin-antithrombin (TAT) and fibrinogen concentrations. To evaluate endothelial integrity proendothelin (proET-1) plasma concentrations were established.
Results of our study demonstrate that proET-1 plasma concentrations were obviously increased in the subjects’ group with end-stage chronic kidney disease (CKD) and renal failure if compared with a group of apparently healthy subjects. The amount of depleted PLT granules was obviously increased in the subjects’ group with end-stage CKD if compared with the group with renal failure. Mean plasma concentrations of TAT and fibrinogen revealed results within the reference range.
It is demonstrated that uraemia is associated with endothelial damage and aberrations in PLT granules morphology in subjects with HD treatment. We hypothesize that increased proET-1 concentrations reflect ongoing stress on endothelial cells amongst others due to uraemia. Biomarkers like proET-1 and aberrations in PLT granules morphology assist in the early detection of procoagulant activity of the endothelium.
Platelet granules depletion; Coagulation; Proendothelin; End-stage kidney disease; Renal failure
The metabolic and functional alterations which occur during the acute phase of nephrotoxic nephritis (NTN) in rats, a model of immune-mediated glomerulonephritis, result from a cooperative interaction between PMNs and platelets (PLTs). In consequence, we hypothesized that fibrinogen (Fg) might play a critical role in this process and, accordingly, we found that defibrination of animals decreased both the acute phase proteinuria in NTN (approximately 70%) as well as the influx of PLTs and PMNs into the glomerulus (approximately 40-50%). In contrast, blockade of the PLT Fg receptor, alpha IIb beta 3, with the RGD peptidomimetic SC-49992 decreased proteinuria (approximately 90%) without substantially altering the influx of PMNs or PLTs. Immunocytochemistry showed a marked increase in beta 3 integrin expression in inflamed glomeruli which was prevented either by PMN or PLT depletion before disease induction. FACS and immunocytochemical analysis of glomerular cell dissociates demonstrated that beta 3 integrin expression was predominantly on intraglomerular PLTs. In vitro, activated PLTs stimulated the PMN respiratory burst, an interaction which could be inhibited by Fg receptor blockade. In sum, acute NTN is accompanied by a marked increase in glomerular beta 3 integrin expression predominantly due to the influx of PLTs which localize to the glomerulus in a PMN-dependent fashion. Fg appears to serve a major role as a coactivating stimulus for PLT-PMNs in situ via alpha IIb beta 3, potentially mediating the PMN respiratory burst which contributes to proteinuria. Fg may also play a subsidiary role in PMN/PLT comigration.
We previously reported that ultraviolet light B (UVB)-treated human platelets (hPLTs) can cause acute lung injury (ALI) in a two-event SCID mouse model in which the predisposing event was Lipopolysaccharide (LPS) injection and the second event was infusion of UVB-treated hPLTs. To delineate contributions of host mouse platelets (mPLTs) and neutrophils in the pathogenesis of ALI in this mouse model, we depleted mPLTs or neutrophils and measured hPLT accumulation in the lung. We also assessed lung injury by protein content in bronchoalveolar lavage fluid (BALF). LPS injection followed by infusion of UVB-treated hPLTs resulted in sequestration of both mPLTs and hPLTs in the lungs of SCID mice, although the numbers of neutrophils in the lung were not significantly different from the control group. Depletion of mouse neutrophils caused only a mild reduction in UVB-hPLTs accumulation in the lungs and a mild reduction in protein content in BALF. In comparison, depletion of mPLTs almost completely abolished hPLTs accumulation in the lung and significantly reduced protein content in BALF. UVB-treated hPLTs bound to host mPLTs, but did not bind to neutrophils in the lung. Aspirin treatment of hPLTs in vitro abolished hPLT accumulation in the lung and protected mice from lung injury. Our data indicate that host mPLTs accumulated in the lungs in response to an inflammatory challenge and subsequently mediated the attachment of transfused UVB-hPLTs. Neutrophils also recruited a small percentage of platelets to the lung. These findings may help develop therapeutic strategies for ALI which could potentially result from transfusion of UV illuminated platelets.
Platelets (PLTs) act in antimicrobial host defense by releasing PLT microbicidal proteins (PMPs) or PLT kinocidins (PKs). Receptors mediating staphylocidal efficacy and PMP or PK release versus isogenic PMP-susceptible (ISP479C) and -resistant (ISP479R) Staphylococcus aureus strains were examined in vitro. Isolated PLTs were incubated with ISP479C or ISP479R (PLT/S. aureus ratio range, 1:1 to 10,000:1) in the presence or absence of a panel of PLT inhibitors, including P2X and P2Y receptor antagonists of increasingly narrow specificity, and PLT adhesion receptors (CD41, CD42b, and CD62P). PLT-to-S. aureus exposure ratios of ≥10:1 yielded significant reductions in the viability of both strains. Results from reversed-phase high-performance liquid chromatography indicated that staphylocidal PLT releasates contained PMPs and PKs. At ratios below 10:1, the PLT antistaphylococcal efficacy relative to the intrinsic S. aureus PMP-susceptible or -resistant phenotype diminished. Apyrase (an agent of ADP degradation), suramin (a general P2 receptor antagonist), pyridoxal 5′-phosphonucleotide derivative (a specific P2X1 antagonist), and cangrelor (a specific P2Y12 antagonist) mitigated the PLT staphylocidal response against both strains, correlating with reduced levels of PMP and PK release. Specific inhibition occurred in the presence and absence of homologous plasma. The antagonism of the thromboxane A2, cyclooxygenase-1/cyclooxygenase-2, or phospholipase C pathway or the hindrance of surface adhesion receptors failed to impede PLT anti-S. aureus responses. These results suggest a multifactorial PLT anti-S. aureus response mechanism involving (i) a PLT-to-S. aureus ratio sufficient for activation; (ii) the ensuing degranulation of PMPs, PKs, ADP, and/or ATP; (iii) the activation of P2X1/P2Y12 receptors on adjacent PLTs; and (iv) the recursive amplification of PMP and PK release from these PLTs.
The present data on the evaluation of platelet (PLT) parameters in Chinese Han population and Tibetans are still limited. The objective of this study was to determine the differences in common PLT indices between Han population and Tibetans in China, through a large-scale investigation of healthy people.
2131 Han people from Chengdu Plain, 1099 Tibetans from Qinghai-Tibet Plateau and 956 Plateau Han migrants were included in this study. All the subjects were healthy people through the health screening. PLT indices were measured with Sysmex XE-2100 and XT-1800i blood cell automatic analyzer.
Compared with Han people in Chendu Plain, Tibetans had higher PLT count (P<0.01) but lower mean platelet volume (MPV), platelet distribution width (PDW) and platelet-large cell ratio (P-LCR) (P<0.01); while Plateau Han migrants had lower PLT count, MPV and P-LCR (P<0.05). When compared with Tibetans, Plateau Han migrants had lower levels of mean PLT count but higher PDW and P-LCR (P<0.05).
There are ethnic differences in PLT indices between Chinese Han population and Tibetans. Based on this finding, it would be reasonable to conduct formal prospective studies to determine the clinical significance of these differences and to explore the effects of genetic background on these indices.
Mean platelet volume (MPV) and platelet count (PLT) are highly heritable and tightly regulated traits. We performed a genome-wide association study for MPV and identified one SNP, rs342293, as having highly significant and reproducible association with MPV (per-G allele effect 0.016 ± 0.001 log fL; P < 1.08 × 10−24) and PLT (per-G effect −4.55 ± 0.80 109/L; P < 7.19 × 10−8) in 8586 healthy subjects. Whole-genome expression analysis in the 1-MB region showed a significant association with platelet transcript levels for PIK3CG (n = 35; P = .047). The G allele at rs342293 was also associated with decreased binding of annexin V to platelets activated with collagen-related peptide (n = 84; P = .003). The region 7q22.3 identifies the first QTL influencing platelet volume, counts, and function in healthy subjects. Notably, the association signal maps to a chromosome region implicated in myeloid malignancies, indicating this site as an important regulatory site for hematopoiesis. The identification of loci regulating MPV by this and other studies will increase our insight in the processes of megakaryopoiesis and proplatelet formation, and it may aid the identification of genes that are somatically mutated in essential thrombocytosis.
This study investigated the relationship between platelet (PLT) serotonin (5-HT) and intestinal permeability in children with pervasive developmental disorders (PDD). Differential sugar absorption and PLT 5-HT were determined in 23 children with PDD. PLT 5-HT (2.0–7.1 nmol/109 PLT) was elevated in 4/23 patients. None exhibited elevated intestinal permeability (lactulose/mannitol ratio: 0.008–0.035 mol/mol). PLT 5-HT did not correlate with intestinal permeability or GI tract complaints. PLT 5-HT correlated with 24 h urinary 5-hydroxyindoleacetic acid (5-HIAA; p = .034). Also urinary 5-HIAA and urinary 5-HT were interrelated (p = .005). A link between hyperserotonemia and increased intestinal permeability remained unsupported. Increased PLT 5-HT in PDD is likely to derive from increased PLT exposure to 5-HT. Longitudinal studies, showing the (in)consistency of abnormal intestinal permeability and PLT 5-HT, may resolve present discrepancies in the literature.
Child development disorders; Pervasive; Platelets; Serotonin; Gastrointestinal; Permeability
CONFLICT OF INTEREST: NONE DECLARED
The collection of platelets by apheresis is considered as a very great progress in transfusion medicine. A larger yield (total number of collected platelets) is obtained if the donor has a greater number of initial platelets and if the separation is done in a shorter time. One of the parameters is also the efficiency of the platelet collection (expressed in percentage) on the value of which different factors may have direct or indirect influence.
To calculate the efficiency of platelet collection with the separator Fenval Baxter AMICUS and to compare the efficiency of platelet collection with this separator in relation to the initial value of donor hematocrit.
Donors and Methods
The donors who participated in this study were divided into groups according to the value of the donor’s ‘hematocrit before separation. Group C consisted of donors whose initial value of the hematocrit was lower or equal to 46%. Group D consisted of donors whose initial value of the hematocrit was higher than 46%. The process was carried out on Fenval Baxter AMICUS. The expected efficiency of the collection was obtained by dividing the total number of collected cells by the expected total number of processed cells, i.e. the total number of cells passed through the equipment.
In the 258 separations which satisfied the fixed criteria were men in 226 cases (87.6%) and women in 32 (12.4%). There is a statically significant difference in the platelet value between the groups and this value is higher in group D than in group C. The average value of platelets before separation was 46.66. The range of minimal and maximal value is from 38.8 to 52.4 ±2.78. The initial value of hematocrits of the donor does not intervene in the length of the separation, but it has a significant effect on the efficiency of the platelet collection. Increases in the number of hematocrits significantly decrease the efficiency of platelet collection. In practice it means that we can base on this fact make a better selection of donors. In this kind selection, one should prefer a donor with a higher number of initial platelets and lower levels of hematocrits. In that way we can collect a more important yield, have a shorter length of separation and increase the efficiency of platelet collection. Its advantage is as well medical because of a more important yield but also financial because of the decrease of the length of the separation and the increase in efficiency. Key words: value of hematocrits, donors, apheresis, platelets, efficiency.
value of hematocrits; donors; apheresis; platelets; efficiency
Blood group A and B antigens are expressed only weakly on platelets (PLTs) of most individuals but are very strongly expressed on PLTs from approximately 1 percent of normal subjects (Type II high expressers). The implications of this trait for transfusion medicine are undefined.
STUDY DESIGN AND METHODS
A family was studied in which two Group B infants were born with neonatal thrombocytopenia, whereas a third infant whose blood group was A2 had a normal PLT count at birth.
Serologic studies demonstrated a maternal antibody that reacted strongly with PLTs from the father and the two group B children in flow cytometry and with GPIIb/IIIa from their PLTs in solid-phase assays. No PLT-specific antibodies were detected in maternal serum sample, but it contained a high-titer immunoglobulin G antibody specific for blood group B. All PLT-reactive antibody in the mother’s serum was removed by absorption with pooled, washed group A and B red cells (RBCs). Studies with monoclonal anti-B and measurement of serum B-glycosyltransferase activity showed that the father and both group B children were Type II high expressers of blood group B.
The findings indicate that high-titer blood group antibodies acquired from the mother can cause thrombocytopenia in infants possessing the Type II high-expresser phenotype despite competition for antibody binding by blood group antigens expressed on RBCs and other tissues.
Platelet concentrate (PC) remains one of the most important support measures in thrombocytopenic patients. An efficient cell separator is a prerequisite for an optimally functioning apheresis setup. Donor blood count may undergo a temporary reduction after the procedure.
The aim was to find the extent of reduction in donor blood count (hemoglobin, hematocrit, white blood cell, and platelet) after plateletpheresis and to evaluate the cell separator for collection efficiency, processing time, and leukoreduction.
Study Design and Methods:
Two hundred and thirty seven procedures performed on the Amicus (N = 121), Fenwal CS-3000 Plus (N = 50) and Cobe spectra (N = 66) in a one year period were evaluated. The procedures performed on the continuous flow centrifugation (CFC) cell separators and donor blood counts (pre and post donation) done were included in the study.
The percent reduction in hemoglobin (HB), hematocrit (HCT), white blood cell (WBC) and platelet count ((PLT ct) was 2.9, 3.1, 9, 30.7 (Mean, N = 237) respectively after the procedure. The post donation PLT ct reduced to < 100×109/L (range 80-100) in five donors (N = 5/237, Amicus). The pre donation PLT ct in them was 150-200×109/L. Collection efficiency (percent) of Amicus (79.3) was better as compared to the other two machines (CS: 62.5, Cobe: 57.5). PC collected on Cobe spectra had <1×106 WBC. The donor pre donation PLT levels had a positive correlation to the product PLT yield (r = 0.30, P = 0.000).
Monitoring donor blood counts helps to avoid pheresis induced adverse events. A cautious approach is necessary in donors whose pre donation PLT ct is 150-200×109/L. The main variable in PLT yield is donor PLT ct (pre donation). High collection efficiency is a direct measure of an optimally functioning cell separator.
Continuous flow cell separator; donor blood count; plateletpheresis; platelet yield; Blood donor; apheresis
TLR9 localizes to a novel intracellular compartment called the T granule to
promote immune signaling by platelets.
Human and murine platelets (PLTs) variably express toll-like receptors (TLRs),
which link the innate and adaptive immune responses during infectious
inflammation and atherosclerotic vascular disease. In this paper, we show that
the TLR9 transcript is specifically up-regulated during pro-PLT production and
is distributed to a novel electron-dense tubular system-related compartment we
have named the T granule. TLR9 colocalizes with protein disulfide isomerase and
is associated with either VAMP 7 or VAMP 8, which regulates its distribution in
PLTs on contact activation (spreading). Preincubation of PLTs with type IV
collagen specifically increased TLR9 and CD62P surface expression and augmented
oligodeoxynucleotide (ODN) sequestration and PLT clumping upon addition of
bacterial/viral ODNs. Collectively, this paper (a) tracks TLR9 to a new
intracellular compartment in PLTs and (b) describes a novel mechanism of TLR9
organization and signaling in human PLTs.
The combination of granulocyte–colony-stimulating factor (G-CSF) and dexamethasone is an effective granulocyte mobilization regimen. The short-term side effects of G-CSF are well studied, but the potential long-term effects of repeated G-CSF stimulation in unrelated volunteer granulocyte donors have not been reported.
STUDY DESIGN AND METHODS
Donors who had received G-CSF three or more times for granulocytapheresis between 1994 and 2002 were identified and attempts were made to contact them if they were no longer active donors. They were matched with control platelet (PLT) donors for sex, age, and approximate number of cytapheresis donations. A health history was obtained and complete blood counts (CBCs) and C-reactive protein (CRP) determined where feasible.
Ninety-two granulocyte donors were identified, and 83 of them were contacted. They contributed to 1120 granulocyte concentrates, or a mean of 13.5 granulocytapheresis procedures per donor (and a mean of 87.5 plateletpheresis procedures per donor). There was no difference in CBCs between the granulocyte donors and the control PLT donors. There was no difference in CRP between the two groups, and no difference in pre- and post–G-CSF CRP in a subset of 22 granulocyte donors. Predefined health events included malignancies, coronary artery disease, and thrombosis. At a median 10-year follow-up, there were seven such events in the granulocyte donors and five in the PLT donors.
Although the number of granulocyte donors studied is small and continued surveillance of healthy individuals after G-CSF is prudent, our data suggest that G-CSF/dexamethasone stimulation appears to be safe.
There are limited data on the evolution of the leukocyte and platelet counts in malaria patients.
In a clinical trial of chloroquine vs. chloroquine plus doxycycline vs. doxycycline alone against Plasmodium vivax (n = 64) or Plasmodium falciparum (n = 98) malaria, the total white cell (WCC) and platelet (PLT) counts were measured on Days 0, 3, 7 and 28 in 57 indigenous Papuans with life long malaria exposure and 105 non Papuan immigrants from other parts of Indonesia with limited malaria exposure.
The mean Day 0 WCC (n = 152) was 6.492 (range 2.1–13.4) × 109/L and was significantly lower in the Papuans compared to the non Papuans: 5.77 × 109/L vs. 6.86 × 109/L, difference = -1.09 [(95% CI -0.42 to -1.79 × 109/L), P = 0.0018]. 14 (9.2%) and 9 (5.9%) patients had leukopaenia (<4.0 × 109/L) and leukocytosis (>10.0 × 109/L), respectively. By Day 28, the mean WCC increased significantly (P = 0.0003) from 6.37 to 7.47 × 109/L (73 paired values) and was similar between the two groups. Ethnicity was the only WCC explanatory factor and only on Day 0.
The mean Day 0 platelet count (n = 151) was 113.0 (range 8.0–313.0) × 109/L and rose significantly to 186.308 × 109/L by Day 28 (P < 0.0001). There was a corresponding fall in patient proportions with thrombocytopaenia (<150 × 109/L): 119/151 (78.81%) vs. 16/73 (21.92%, P < 0.00001). Papuan and non Papuan mean platelet counts were similar at all time points. Only malaria species on Day 0 was a significant platelet count explanatory factor. The mean D0 platelet counts were significantly lower (P = 0.025) in vivax (102.022 × 109/L) vs. falciparum (122.125 × 109/L) patients.
Changes in leukocytes and platelets were consistent with other malaria studies. The Papuan non Papuan difference in the mean Day 0 WCC was small but might be related to the difference in malaria exposure.
There are multiple benefits to transfusing only ABO identical blood components. Historically our institution routinely transfused ABO non-identical platelets (PLTs) and cryoprecipitate to surgical patients. In April 2005, we implemented a policy of transfusing only ABO identical components whenever feasible, regardless of outdating/logistic considerations.
Technical staff closely monitored product usage and adjusted blood center orders based on recent utilization and planned transfusions. When unable to provide ABO identical PLTs ABO compatible platelets were washed to remove incompatible plasma. Data on outdating were collected for eighteen months before and after implementation. We compared transfusion reaction and red cell alloimmunization incidence for four years preceding (2001–2004) and subsequent (2006–2009) to implementation.
In the year following implementation, only 11 of 410 surgical patients received ABO non-identical platelets (2.7%). There was a 5.6% increase in outdating of platelets. Transfusing ABO identical components was associated with significant reductions in febrile (−46%; 8.0 to 4.3 per 10,000 components; p<0.0001) and allergic transfusion reactions (−23%; from 7.0 to 5.4 per 10,000 components; p=0.025). A progressive reduction in de novo red cell alloimmunization incidence also occurred (−50% by 2009; p=0.03).
Providing ABO identical platelets to almost all patients was feasible in our setting by changing ordering and inventorying procedures, and making the ABO identical policy a staff priority. Unexpected and striking reductions in febrile and allergic reactions, and red cell alloimmunization were observed, of uncertain causal relationship to this ABO policy change, which will require further study.
Concentrating and washing apheresis platelets (APs) substantially reduce the number of allergic transfusion reactions likely due to removal of plasma. However, these processes may damage platelets. This study evaluated whether concentrating or washing APs decrease the Corrected Count Increment (CCI).
Study Design and Methods
This retrospective study evaluated individuals who initially received unmanipulated APs and subsequently received concentrated and/or washed APs at a large university hospital between 1998 and 2009. Concentrated units were prepared by reducing the plasma volume of APs by a goal of >67%. Washed units were prepared by washing the APs with 1L normal saline. The CCI (plt × m2/uL) for all transfusions was calculated. Hypothesis testing was performed with Student’s t-tests for continuous variables and chi-square tests for dichotomous variables.
We evaluated 121 individuals; 46 patients who received unmanipulated, concentrated and then washed APs, 59 patients who received unmanipulated and then concentrated APs; and 16 patients who received unmanipulated and then washed APs. Patient demographics were similar among the three groups. The mean CCI for unmanipulated AP transfusions at 0–2 hours post transfusion were significantly higher than concentrated and washed platelet transfusions (p<0.001). However, when accounting for platelet loss due to manipulation, concentrating APs did not impact the CCI, but the CCI remained significantly lower for washed products at all time points post transfusion (40.7% mean reduction at 20–24 hours, p<0.001).
Washing APs significantly reduces platelet count recovery and survival, as demonstrated by a significantly reduced CCI.
corrected count increment (CCI); allergic transfusion reaction (ATR); platelet; wash; concentrate; urticaria; hives; anaphylaxis; premedication