Platelet transfusion in adults: An update

Quality assessment of the preparation and storage of leukocyte-depleted pooled platelet concentrates

OBJECTIVE

To explore the feasibility of using a disposable platelet storage bag containing a leukocyte filter to prepare leukocyte-depleted pooled platelet concentrates with the buffy coat method.

METHODS

150 bags of whole blood samples (400 mL/bag) were stored overnight at 22 ± 2°C, and buffy coats were separated on Day 2, then 5 units of ABO homotypic buffy coat and 1 unit of plasma were pooled into a disposable platelet storage bag containing a leukocyte filter to prepare leukocyte-depleted pooled platelet concentrates and stored in a Platelet Agitator. On Day 2, 4, 5 and 7 after the collection of whole blood, platelet content, pH value, pO2, pCO2, glucose (GLU), ATP, and other quality indicators were measured.

RESULTS

The quality indicators of leukocyte-depleted pooled platelet concentrates met the requirements for leukocyte-depleted aphaeresis platelets in the Chinese national standard Quality Requirements for Whole Blood and Blood Components (GB18469-2012). With the prolongation of storage time, MPV and PDW of platelets gradually increased, pH value, bicarbonate, and GLU gradually decreased, LA, LDH, and ATP gradually increased, pO2 slightly increased, pCO2 decreased, and HSR had no significant change. ESC decreased significantly on Day 7, CD62p decreased first and then increased, sP-selectin and GP V increased first and then decreased, but the results on Day 7 were higher than those on Day 2.

CONCLUSION

The quality of leukocyte-depleted pooled platelet concentrates prepared by the buffy coat method using disposable platelet storage bags containing a leukocyte filter was comparable to that of leukocyte-depleted apheresis platelets, and could be used clinically.

Eltrombopag treatment in thrombocytopenia following hematopoietic stem cell transplantation: A multicenter real-world experience

INTRODUCTION

Thrombocytopenia is among the most common complications following hematopoietic stem cell transplantation and is associated with increased mortality and morbidity with no standard treatment yet. In this multicenter and retrospective study, we aim to present our multi-center experience of Eltrombopag treatment in patients with isolated thrombocytopenia following HSCT.

MATERIAL-METHOD

A total of 73 patients from 5 centers who underwent autologous or allogeneic stem cell transplantation, had no primary disease relapse, all of whom had neutrophil engraftment, complete chimerism, and who were diagnosed with Prolonged Isolated Thrombocytopenia (PIT) or Secondary Failure Of Platelet Recovery (SFPR) were included in the study. The patients were initiated on Eltrombopag at a dose of 50-150 mg. Complete response was defined as a platelet count >50×109/L for 7 consecutive days with no transfusion support.

RESULTS

A total of 50.3% of the patients underwent Autologous and 49.7% Allogeneic Stem Cell Transplantation, 54.8% were diagnosed with PIT, and 45.2% were diagnosed with SFPR, and the treatment with 50-150 mg/day Eltrombopag was initiated on the median day +42. Complete response was achieved in 71.2% of these patients on the median day 23 of the treatment. No significant effects of the initial dose (50-150 mg/day) were detected in the Complete Response in the multivariate analysis on response. An insufficient number of Megakaryocytes in the bone marrow before Eltrombopag treatment was determined as an independent risk factor in determining the response (OR 3.57, 95% CI 1.21-10.55). The overall survival of the patients who did not respond to Eltrombopag was found to be significantly worse than that of patients who responded (p=0.022, HR:2.74, 95% CI 1.12-6.54).

CONCLUSION

As a result of the present study, Eltrombopag treatment was found to be effective and safe in thrombocytopenia that develops following hematopoietic stem cell transplantation. It was concluded that its use may be more effective in patients with sufficient bone marrow megakaryocytes before the treatment and an initial dose of 50 mg/day may be appropriate in terms of cost, effectiveness, and toxicity. Large-scale randomized and controlled prospective studies are needed to determine the roles of Eltrombopag treatment in patients with post-transplant PIT and SFPR.

Engineering unactivated platelets for targeted drug delivery

As a vital component of blood, platelets play crucial roles in hemostasis and maintaining vascular integrity, and actively participate in inflammation and immune regulation. The unique biological properties of natural platelets have enabled their utilization as drug delivery vehicles. The advancement and integration of various techniques, including biological, chemical, and physicochemical methods, have enabled the preparation of engineered platelets. Platelets can serve as drug delivery platforms combined with immunotherapy and chemokine therapy to enhance their therapeutic impact. This review focuses on the recent advancements in the application of unactivated platelets for drug delivery. The construction strategies of engineered platelets are comprehensively summarized, encompassing internal loading, surface modification, and genetic engineering techniques. Engineered platelets hold vast potential for treating cardiovascular diseases, cancers, and infectious diseases. Furthermore, the challenges and potential considerations in creating engineered platelets with natural activity are discussed.

Discussion on the recruitment strategy for apheresis platelet donors in Chongqing during a public health emergency. Front Public Health 2024;12:1365433. [PMID: 38651129 PMCID: PMC11034425 DOI: 10.3389/fpubh.2024.1365433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Objective

This study aimed to analyze the population characteristics of apheresis platelet donors in Chongqing Province and provide a scientific basis for the development of precise and efficient recruitment strategies. The ultimate goal is to increase the number of regular platelet donors in preparation for public health emergencies.

Methods

This study involved 53,089 blood donors who donated apheresis platelets to the Chongqing Blood Center from 2020 to 2022. Data regarding age, sex, blood type, education level, occupation, and frequency of blood donation were collected and analyzed to identify factors influencing platelet donation.

Results

Between 2020 and 2022, the majority of apheresis platelet donors in Chongqing were aged 25-35 years, with a male-to-female ratio of 2.6:1. The ABO blood group distribution was O > A > B > AB. The apheresis platelet donors mainly consisted of college students, and the donors who had donated only once accounted for the greatest proportion.

Conclusion

Based on the population characteristics of apheresis platelet donors in Chongqing, blood collection and supply organizations must refine emergency blood collection and supply plans during public health emergencies. This study underscores the importance of developing precise and efficient recruitment strategies for apheresis platelet donors and expanding the pool of regular apheresis platelet donors. These measures are essential to ensure the timely, safe, and effective use of clinical blood resources during public health emergencies.

The appropriateness of platelet transfusions in hematological patients and the potential for improvement

BACKGROUND

Hematology patients are intensive platelet users. In clinical practice, a substantial proportion of platelet (PLT) transfusions are routinely administered outside the guidelines despite compelling evidence for recommendations. Those unnecessary PLT transfusions are an unjustified extra burden on a scarce healthcare resource and may also be detrimental to the patients. This study aims to evaluate indications and assess the appropriateness of PLT transfusion, as well as to identify common discrepancies and propose modalities for better compliance with guidelines.

MATERIAL AND METHODS

The audit of all PLT orders for adult hematological inpatients was conducted over 2 months. The assessment was performed using guidelines for PLT transfusion. Patient demographic, clinical, and transfusion data were collected from hospital electronic medical records.

RESULTS

Based on 286 PLT orders, 344 PCs were transfused to 67 patients: 235 (82.2%) prophylactical due to low PLT count, 34 (11.9%) preprocedural and 17 (5.9%) therapeutic. Overall, 105 (36.77%) PLT transfusions were inappropriate: 78 (33.2%) of all prophylactic PLT transfusions due to low PLT count, 17 (50%) off all preprocedural and 10 (58.8%) of all therapeutical transfusion. The major reason for PLT transfusion inappropriateness was transfusion above the recommended threshold. Double units of PCs were transfused in 36.7% of all PLT transfusions and 32.4% of them were considered inappropriate.

CONCLUSION

Our audit of PLT transfusion practice found a large proportion of inappropriate PLT transfusions. Based on the most common deviations from the guidelines a variety of targeted measures for improvement are proposed.

An overview of red blood cell and platelet alloimmunisation in transfusion

Post-transfusion alloimmunisation is the main complication of all those observed after one or more transfusion episodes. Alloimmunisation is observed after the transfusion of red blood cell concentrates but also of platelet concentrates. Besides alloimmunisation due to antigens carried almost exclusively by red blood cells such as those of the Rhesus-Kell system, alloimmunisation often raises against HLA antigens; the main responsibility for that, apart from platelet transfusions, lies with residual leukocytes in the products transfused, hence the central importance of effective leukoreduction right from the blood product preparation stage. Alloimmunization is not restricted to transfusion, but it is also observed during pregnancies, carrying out microtransfusions of blood from the fetus immunizing the mother through the placenta (in a retrograde way). Preexisting maternal-fetal immunization can complicate a transfusion program and intensify the creation of alloantibodies in several blood and tissue group systems. The occurrence of autoantibodies, created by several pathogenic reasons, can also interfere with the propensity of certain recipients of blood components to produce alloantibodies. The genetic condition of individuals is in fact strongly linked to the ability or not to recognize antigenic variants foreign to their own biological program and mount an alloimmune response. Some hemoglobin diseases, in carriers of which transfusions can be iterative and lifelong, are complicated by frequent alloimmunizations and amplification of the complications of these alloimmunizations, imposing even stricter transfusion rules. This review details the mechanisms favoring the occurrence of alloimmunization and the immunological principles for the production of molecular and cellular tools for alloimmunization. It concludes with the main preventive measures available to limit the occurrence of these frequent complications of varying severity but sometimes severe.