Increased platelet-leucocyte complexes do not result in coagulation activation in plateletpheresis donors

BACKGROUND

Although plateletpheresis donation is commonly accepted as a safe procedure, its influence on platelet function, coagulation system and fibrinolysis is not completely elucidated.

OBJECTIVES

In this study, we tried to assess the effects of plateletpheresis on donor's hemostasis system by measuring platelet activation, development of platelet-leukocyte aggregates, and coagulation activation.

STUDY DESIGN

Prospective observational study.

METHODS

We used flow cytometry to determine the levels of platelet-monocyte complexes (PMC) and platelet-neutrophil complexes (PNC). sP-selectin and prothrombin fragment (PF) 1 + 2 values were determined by ELISA.

RESULTS

The PMC levels increased significantly seven days after apheresis in comparison with just after apheresis and 24 h after apheresis (p < 0.05). The PNC levels increased significantly seven days after apheresis compared to immediately after apheresis (p < 0.05). sP-selectin values decreased significantly immediately after apheresis (p < 0.05). While sP-selectin values increased seven days after apheresis in comparison with immediately after apheresis and 24 h after apheresis, but there were not statistically significant differences for sP-selectin levels (p > 0.05). PF1 + 2 levels decreased significantly immediately after apheresis compared to pre-apheresis (p < 0.05) and increased 24 h after apheresis and seven days after apheresis, but these differences were not statistically significant.

CONCLUSION

We concluded that plateletpheresis affects platelet activation but does not cause any change in coagulation activation.

The effect of thrombocytapheresis on hemogram and biochemistry parameters in patients with essential thrombocytemia

BACKGROUND

Essential thrombocythemia is one of the chronic myeloproliferative neoplasms characterized by clonal proliferation of myeloid cells with variable morphological maturation and hematopoietic activity.It is characterized by excessive clonal platelet production with a tendency to thrombosis and bleeding. Thrombocytapheresıs is the removal of platelets by apheresis techniques. Thrombocytapheresıs is generally recommended in patients with essential thrombocythemia with acute, severe thrombotic or hemorrhagic events.

METHODS

The study included 39 patients who were diagnosed with essential thrombocythemia, started cytoreductive and aspirin therapy, and underwent thrombocytapheresıs due to the development of acute severe thrombotic or hemorrhagic events, diagnosed in the adult hematology clinic of İnönü University Turgut Ozal Medical Center. Hemogram and biochemistry values of the patients were scanned retrospectively.

RESULTS

After thrombocytapheresıs, a statistically significant difference was found between the first and last measurements of hemoglobin, mean platelet volume, White blood cell, neutrophil, platelet, platelet distribution width, creatine, lactate dehydrogenase, fibronogen and calcium levels of the patients.

CONCLUSION

The use of thrombocytapheresıs in patients with essential thrombocytosis causes a rapid decrease in platelet values as well as an effect on hemogram and biochemistry parameters. Other hemogram and biochemistry parameters such as platelet value should be monitored in patients.

Regulated upon activation, normal T cells expressed and secreted (CCL5) in platelet concentrate: Role of mode of preparation and duration of storage

BACKGROUND AND OBJECTIVES:

Platelet concentrates (PCs) can be prepared in several different ways, and they can be stored over few days before the use. Regulated on activation, normal T cells expressed and secreted (RANTES) levels in these concentrates may vary depending on the type of preparation and duration of storage of this component. We measured RANTES levels in platelet supernatants in different preparations and with different storage duration.

MATERIALS AND METHODS:

Fifteen PCs were prepared by platelet-rich plasma (PRP) and buffy coat (BC) method each. Forty-two single donor platelets (SDPs) were prepared using cell separators Cobe Spectra, Trima Accel, and Amicus. Filtered PCs were prepared using labside and bedside filters. The supernatants were collected after 1, 18, 65, and 112 h of preparation. SDP samples were taken on the 0 day, 3^rd day, and 5^th day. In filtered PC, pre- and post-filtration samples were taken, and aliquots were frozen at − 56°C for the measurement of RANTES.

RESULTS:

RANTES at 1 h was 1210 ± 560 pg/ml in PRP-PC, 1384 ± 463 pg/ml in BC-PC. At 112 h, 1617 ± 451 pg/ml and 1949 ± 134 pg/ml, respectively. In SDP, 0-day level was 1850 ± 278 pg/ml and >2000 pg/ml on 5^th day. In prestorage, filtered PC RANTES was 1035 ± 496 pg/ml, and in the poststorage sample, it was 310 ± 508 pg/ml. With bedside filters, presample showed 1243 ± 832 pg/ml and postsample showed 556 ± 748 pg/ml.

CONCLUSION:

The concentration of RANTES increased continuously from 1 h to 5 days of storage in all PCs. After 65 h, BC-PC showed higher levels of RANTES compared to PRP-PC. Filtered PRP-PCs appear to be the best in terms of low RANTES to prevent allergic reactions and cultures negative.

The effect of platelet apheresis collection on some immunological factors in donors using two different apheresis devices

INTRODUCTION

The aim of this study was to evaluate and compare two different apheresis and changes in some immunological factors in donors.

MATERIAL AND METHODS

The cross-sectional study was performed from January 2017 to September 2018. Fifty six male blood donors were randomly divided into two groups. CD4, CD8, and CD25 markers by flow cytometry, and TGFBeta by real-time polymerase chain reaction (RT-PCR) method were done before and 7 days after the apheresis procedure. Independent Sample t-test, Mann-Whitney U Test, Wilcoxon signed ranked test, and Fisher exact test were used.

RESULTS

WBC in MCS+ group after donation is significantly higher than before donation (P < 0.05) but no significant difference was seen between MCS+ and Trima groups in these two indicators. But in CD4, CD25, and TGFBeta, there was no significant difference between the two groups.

CONCLUSION

There was no significant difference on CD4, CD25, and TGFBeta gene 7 days after donation.

Granulocyte and monocyte CD11b expression during plasma separation is dependent on complement factor 5 (C5) - an ex vivo study with blood from a C5-deficient individual

The aim of the study was to investigate the role of complement factor 5 (C5) in reactions elicited by plasma separation using blood from a C5-deficient (C5D) individual, comparing it to C5-deficient blood reconstituted with C5 (C5DR) and blood from healthy donors. Blood was circulated through an ex vivo plasma separation model. Leukocyte CD11b expression and leukocyte-platelet conjugates were measured by flow cytometry during a 30-min period. Other markers were assessed during a 240-min period. Granulocyte and monocyte CD11b expression did not increase in C5D blood during plasma separation. In C5DR samples granulocytes CD11b expression, measured by mean fluorescence intensity (MFI), increased from 10481 ± 6022 (SD) to 62703 ± 4936, and monocytes CD11b expression changed from 13837 ± 7047 to 40063 ± 713. Granulocyte-platelet conjugates showed a 2.5-fold increase in the C5DR sample compared to the C5D sample. Monocyte-platelet conjugates increased independently of C5. In the C5D samples, platelet count decreased from 210 × 10⁹ /L (201-219) (median and range) to 51 × 10⁹ /L (50-51), and C3bc increased from 14 CAU/mL (21-7) to 198 CAU/mL (127-269), whereas TCC formation was blocked during plasma separation. In conclusion, up-regulation of granulocyte and monocyte CD11b during plasma separation was C5-dependent. The results also indicate C5 dependency in granulocyte-platelet conjugates formation.

The role of thrombocytapheresis in the contemporary management of hyperthrombocytosis in myeloproliferative neoplasms: A case-based review

Extreme thrombocytosis induces an acquired thrombotic-hemorrhagic diathesis, and left uncontrolled is a harbinger of potentially fatal vascular complications. Currently, cytoreduction with medical therapy remains the mainstay of hyperthrombocytosis management. However, it offers a less-than-ideal option in situations where a rapid reduction in platelets is urgently needed, as in the presence of vital end-organ ischemia or to ameliorate of life-threatening hemorrhage. The role of thrombocytapheresis, or plateletpheresis, in hyperthrombocytosis has become increasingly obsolete given the proactive titration of cytoreductive therapies and early identification and correction of reversible causes of reactive thrombocytosis. Despite its narrowed indications, plateletpheresis continues to offer a valuable temporizing measure in platelet count reduction before cytoreductive agents exert their maximal effect. In this context, it is important for the treating physician to be aware of the symptoms and risks associated with hyperthrombocytosis to inform best clinical practices. In this review, we discuss the role of plateletpheresis in the modern-day management of hyperthrombocytosis in patients with myeloproliferative neoplasms through a case based review of the literature. It becomes apparent throughout the discussion that the decision to perform plateletpheresis should be individualized based upon the clinical scenario, degree of thrombocytosis, available infrastructure and every patient's risk profile.

Double dose plateletpheresis by continuous and intermittent flow devices increases platelet–neutrophil complex formation in healthy donors without noticeable neutrophil activation

Several reports have demonstrated that during a single plateletpheresis procedure, platelets may form heterotypic aggregates which may predispose certain donors to thrombotic complications. In this study, changes in the expression of neutrophil adhesion molecules (CD11b/CD18, CD50/54, CD62L) and platelet-neutrophil complex (PNC) formation were investigated by a flow cytometric method in healthy donors following a double dose plateletpheresis (DDP) procedure. Our results show that DDP which are carried out by the Fresenius AS.TEC 204 and Haemonetics MCS+ cause a significant increase in PNC formation in donors. Additionally, the Fresenius AS.TEC 204 device caused a decrease in CD62L expression which is a sign of mild neutrophil activation. Although the clinical significance of these laboratory changes is not clear, the occurrence of neutrophil activation and increased PNC formation might predispose certain donors to thrombotic complications following DDP.

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.

Phosphatidylserine exposure in platelet concentrates during the storage period: differences between the platelets collected with different cell separators

BACKGROUND AND OBJECTIVES

Platelet alterations occur during the production and storage of platelet concentrates, the so called "storage lesion". We studied the platelet alterations during the storage period in apheresis concentrates, employing flow cytometry for phosphatidylserine (PS) detection on platelets during the five days of storage.

MATERIAL AND METHODS

Twenty-seven single donor platelet concentrates harvested with the Cobe Trima, Baxter Amicus, or Haemonetics MCS+ were analyzed for PS exposure by flow cytometry on the day of production (day 1) and on days 3 and 5 of storage. Furthermore PS expression was analyzed in platelet donors' blood samples withdrawn before plateletpheresis.

RESULTS

PS expression on platelets gave the following median values: in blood donors before apheresis it was 1.12% (0.13-1.78) in platelets concentrates on the first day (2 h after apheresis) 2.06% (0.66-15.2), the third day 6.57% (1.98-51.13) and the fifth day 23.04% (3.86-80.23). All differences between median values of PS expression in blood samples before apheresis, and platelets concentrates on days 1, 3 and 5 of storage, are statistically significant. The expression of PS in platelet concentrates was analyzed in relation to the blood cell separator used for the collection procedure and showed the following results: on day 1 the median values of PS in platelet concentrates collected with the three different blood cell separators, Trima, Cobe and MCS, did not show statistically significant differences. On day 3, the platelets concentrates collected with the Trima and with the MCS showed differences that were statistically significant. Those were respectively 10.59% (4.56-51.13) and 3.53% (1.98-12.61), p = 0.005. The PS expression in platelet concentrates collected with the Trima and MCS showed differences that are also statistically significant on day 5 at respectively 32.4% (9.61-80.23) and 8.57% (3.86-48.42), p = 0.005.

CONCLUSIONS

PS exposure in platelet concentrates on days 3 and 5 rise to levels that could compromise the quality of the platelet units. Improvements in standardized platelet quality controls, and in platelet collection systems are required to reduce the storage lesions in platelets concentrates.

Binding of activated platelets to WBCs in vivo after transfusion

BACKGROUND

During preparation and storage of apheresis concentrates, platelets are being activated. One of the alterations that occur during this process is an increased expression of P-selectin (CD62p) on the cytoplasmic surface of platelets. This neoepitope represents a ligand for the binding of platelets to WBCs. It has been suggested that the activation of platelets is associated with the sequestration of platelets after transfusion. In this in vivo study, the binding of platelets to WBCs was analyzed following transfusion of platelet concentrates (PCs).

STUDY DESIGN AND METHODS

Double apheresis concentrates were prepared with two different cell separators. One of the split products was stored for 1 to 2 days and the other one for 3 to 5 days. Flow cytometry was applied to analyze the degree of platelet activation in vitro, and also to measure the extent of platelet binding to WBC subclasses in vivo after transfusion into patients.

RESULTS

The results of this study show that platelet activation occurs during apheresis and storage of PCs. After transfusion of the PCs, no significant binding of platelets to T or B-cells could be detected. However, a significant binding of platelets to monocytes and neutrophil granulocytes occurs. While in Baxter PCs stored for 1-2 days the amount of platelet-leukocyte aggregates in vivo was higher compared to COBE PCs, no such difference could be detected anymore for the PCs stored for 3-5 days.

CONCLUSION

This study demonstrates that binding of activated platelets occurs to monocytes and neutrophil granulocytes but not to T- and B-cells in the circulation after transfusion. In addition, the interaction of platelets and WBCs is dependent on the degree of P-selectin expression. Platelets showing a higher degree of activation adhere to WBCs to a higher degree than nonactivated platelets.

Cytokine levels as performance indicators for white blood cell reduction of platelet concentrates

BACKGROUND AND OBJECTIVES

With the implementation of universal white blood cell (WBC) reduction in the UK, in-process WBC-reduction filters for pooled buffy coat (BC)-derived platelet concentrates (PCs) and apheresis methods are used routinely for the production of WBC-reduced PCs. While these strategies meet the specification for WBC reduction (< 5 x 10(6) WBCs/unit), the products from these processes may differ depending on the process employed and its performance. The aim of this study was therefore to investigate whether PCs prepared using various WBC-reduction processes are sufficiently depleted of WBCs to limit cytokine accumulation during storage and to assess if cytokine levels detected in platelet products can serve as indicators of acceptable platelet activation as a result of the WBC-reduction process.

MATERIALS AND METHODS

We measured the levels of cytokines predominantly derived from WBCs [e.g. interleukin-8 (IL-8)] and platelets [e.g. regulated on activation, normal, T-cell expressed, and secreted (RANTES) and transforming growth factor-beta(1) (TGF-beta(1))] under the present experimental conditions in different WBC-reduced PCs, i.e. PCs prepared from three different WBC-reduction filters and control non-filtered PCs using pooled BCs from the same donors and three apheresis types. Supernatant plasma was collected at the beginning (day 1) and end (day 5) of the shelf life of each PC, and the cytokine content was determined using appropriate enzyme-linked immunosorbent assays (ELISAs). Process efficiency was assessed by platelet yield and residual WBC count.

RESULTS

We found that products from the apheresis process involving a filtration step (Haemonetics MCS+) showed a lower cytokine content on both day 1 and day 5 in comparison with the fluidized bed (COBE Spectra) or elutriation (Amicus) processes. WBC reduction of BC-PCs of the same origin using three different filters showed comparable levels of cytokines on day 1 in all units. After storage for 5 days, the levels of IL-8 remained essentially unchanged in filtered BC-PCs but increased by more than threefold in control non-filtered BC-PCs, suggesting IL-8 release by residual WBCs present in the control PCs. The concentration of platelet-derived cytokines such as RANTES and TGF-beta(1), however, increased significantly in all filtered and control non-filtered PCs during the storage period.

CONCLUSION

These results show that markers of cytokine release from both WBCs and platelets are useful indicators of the performance and efficacy of the WBC-reduction process and of platelet quality.

Evidence for de novo synthesis of cytokines and chemokines in platelet concentrates

BACKGROUND AND OBJECTIVES

Inflammatory cytokines in platelet concentrates (PC) may cause side-effects such as febrile non-haemolytic transfusion reactions. The maximum white blood cell (WBC) content tolerable to avoid the accumulation of cytokines, and whether these cytokines originate from degranulating leucocytes or de novo synthesis during storage, had not been investigated prior to this study.

MATERIAL AND METHODS

We investigated the secretion of interleukin (IL)-1beta, IL-2, IL-6, IL-8, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) and quantified the appropriate expression of corresponding mRNA in PC with regard to different levels of WBC contamination and storage times. In addition we tested the viability of WBCs during PC storage (by staining with 7-aminoactinomycin D) and their ability to perform de novo cytokine synthesis (by using superantigen stimulation).

RESULTS

We detected a statistically significant increase of IL-1beta, IL-6, IL-8 and TNF-alpha in PC with > or = 108 WBCs. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) showed increasing mRNA expression of the respective cytokines depending on the number of WBC present. On day 5 of storage, WBC viability was > 80% and the leucocytes were still able to produce cytokines de novo.

CONCLUSIONS

These data show clear evidence for de novo synthesis of cytokines in PC. The cytokine pattern supports the hypothesis that activated monocytes are responsible for this cytokine synthesis. PC with a WBC contamination of > or = 108 contain inflammatory mediators in clinically relevant concentrations.

Collection of autologous monocytes for dendritic cell vaccination therapy in metastatic melanoma patients

BACKGROUND

Dendritic cells (DCs) for immunotherapy of malignant melanoma can be generated from partially enriched monocytes prepared from PBMNCs. The feasibility of a single steady-state leukapheresis procedure to enrich monocytes for a complete vaccination series with up to 10 vaccinations was investigated.

STUDY DESIGN AND METHODS

Thirty-eight patients (27 males and 11 females) with metastatic melanoma were enrolled in the study. All leukapheresis procedures were performed by a continuous flow method (Spectra, Cobe BCT) with a standard MNC program.

RESULTS

An average of 11.7 L (range, 8-14 L) of whole blood was processed within 197.3 +/- 23.7 minutes, and a mean of 13.5 +/- 5.7 x 109 WBCs in a final volume of 191.0 +/- 24.2 mL was collected. The MNC purity in the apheresis component was 81.5 +/- 15.1 percent, from which 29.8 +/- 14.7 percent were monocytes. Thus, 11.0 +/- 5.0 x 109 MNCs and 3.2 +/- 2.0 x 109 monocytes were collected per procedure. Linear regression analysis revealed a high correlation between the absolute number of monocytes in peripheral blood before the apheresis procedure and the number of monocytes in the collected component (r=0.74, p < 0.0001). For the generation of DCs, 1.6 +/- 0.8 x 109 MNCs were plated into culture dishes; 3.2 +/- 1.8 percent of the cultured cells matured to DCs, which resulted in 56.5 +/- 49.4 x 106 DCs (range, 6.3-178) per patient for the complete vaccination series.

CONCLUSION

A target dose of monocytes for the complete vaccination series could be obtained by a single convenient, safe, steady-state leukapheresis procedure in each patient without the need for G-CSF mobilization. The absolute number of monocytes in peripheral blood before the apheresis procedure is the best predictive variable for the yield of monocytes in the apheresis component.