Transfusion efficacy of ABO major-mismatched platelets (PLTs) in children is inferior to that of ABO-identical PLTs

Impact of dose and storage duration of platelet concentrates on platelet recovery between ABO identical and ABO non-identical random donor platelet transfusions in hemato-oncology patients

INTRODUCTION AND OBJECTIVES

It is challenging to adopt a policy of ABO identical platelet transfusion in hemato-oncological patients because of the high demand. Moreover, there are no global standards for the management of ABO non-identical platelet transfusions due to limited evidence. The current study compared the impact of dose and storage duration of platelets on percent platelet recovery (PPR) at 1 h and 24 h between ABO identical and ABO non-identical platelet transfusions in hemato-oncological conditions. The other objectives were to assess the clinical efficacy and compare adverse reactions between the two groups.

METHODS

A total of 130 random donor platelet transfusion episodes (81 ABO identical and 49 ABO non-identical) were evaluated in 60 eligible patients with different malignant, as well as non-malignant, hematological conditions. All analysis was performed using two-sided tests, and p-values <0.05 were considered significant.

RESULTS

The PPR at 1 h and 24 h was significantly higher in ABO identical platelet transfusion. Platelet recovery and survival were not affected by the gender, dose or storage duration of platelet concentrate. Aplastic anemia and myelodysplastic syndrome (MDS) disease conditions were observed to be independent risk predictors for 1-h post-transfusion refractoriness.

CONCLUSION

ABO identical platelets have higher platelet recovery and survival. Both ABO identical and ABO non-identical platelet transfusions have similar efficacy in controlling bleeding episodes up to World Health Organization (WHO) grade two. Assessment of other factors, such as platelet functional properties in the donor, anti-HLA and anti-HPA antibodies, may be needed to better understand the platelet efficacy of platelet transfusions.

Transfusion outcomes and clinical safety of ABO-nonidentical platelets transfusion: A systematic review and meta-analysis

BACKGROUND

ABO-nonidentical platelets transfusion has been frequently employed to address clinical platelets insufficiencies. The significance of ABO compatibility for platelets transfusion is not clearly defined. This study is aimed to explore the transfusion outcomes and clinical safety of ABO-nonidentical platelets transfusion.

STUDY DESIGN AND METHODS

A systematic articles search was performed for eligible studies published up to November 30, 2023 through the PubMed, Embase, Cochrane library, Chinese National Knowledge Infrastructure database, Wanfang database and SinMed. Meta-analysis Of Observational Studies in Epidemiology study guidelines for observational studies and Newcastle Ottawa bias scale were implemented to assess studies. Meta-analysis was performed using Manager 5.3. This study is registered with PROSPERO, number CRD42023417824.

RESULTS

A total of 11 retrospective cohort studies and 7 prospective cohort studies with a sample size of 104,359 platelets transfusions were included. There was significant difference in transfusion effectiveness between the ABO-identical and ABO-nonidentical platelets transfusions (RR 1.20, 95 % CI 1.11-1.38, P < 0.00001, I2 = 21 %), also the ABO-identical platelets transfusions showed more platelets increment than ABO-nonidentical ones, but it was not statistically significant (MD 0.34, 95 % CI - 0.01 to 0.70, P = 0.06, I2 = 0 %). Allergy and fever occurred more in ABO-nonidentical platelets transfusions in terms of adverse reactions (RR 0.63, 95 % CI 0.41-0.96, P = 0.03, I2 = 0 %; RR 0.59, 95 % CI 0.37-0.94, P = 0.03, I2 = 31 %). When it comes to the mortality, the ABO-identical platelets transfusions did not statistically improve survival in patients who received multiple platelets transfusions (RR 0.77, 95 % CI 0.72-0.83, P = 0.17, I2 = 38 %) and who only received less than 3 transfusions (RR 0.74, 95 % CI 0.52-1.06, P = 0.10, I2 = 47 %) compared with the ABO-nonidentical platelets transfusions.

CONCLUSION

In comparison to ABO-identical platelets transfusions, nonidentical platelets transfusions exhibited lower transfusion efficacy. However, the clinical safety between these two groups was similar, which indicated that ABO-nonidentical transfusions are acceptable, albeit inferior to ABO-identical ones.

Blood donor genotyping for prediction of blood group antigens: Results from 5 years' experience (2017-2022)

BACKGROUND AND OBJECTIVES

For 5 years, routine genotyping has been performed for selected blood groups of blood donors in the Copenhagen Capital Region, Denmark. The result is summarized in the following.

MATERIALS AND METHODS

Genotyping was carried out by an external service provider using the competitive allele specific PCR (KASP) technology. The genotypes were returned to the blood bank and translated into phenotypes by a proprietary IT application.

RESULTS

In total, 65 alleles from 16 blood group systems (ABO, MNS, Rh, Lutheran, Kell, Duffy, Kidd, Diego, Yt, Dombrock, Colton, Landsteiner-Wiener, Cromer, Knops, Vel, secretor status) and the HPA1, HPA5 and HPA15 antigens were interrogated. After translation, phenotypes were imported into the laboratory information management system of the blood bank. The results from 31,538 genotyped blood donors were used to calculate the allele frequencies for a Danish blood donor population. ABO genotyping was done for sample ID purposes. Determination of the 1061delC single nucleotide polymorphism (SNP) (NM_020469.2), most frequently characteristic of ABO*A2, was validated against a series of 1287 samples with Dolichos biflorus lectin determination of the A1 phenotype.

CONCLUSION

We report allele frequencies and phenotype frequencies for 16 blood groups from a total of 31,538 genotyped blood donors. Blood products were supplied from a total of 64,312 active blood donors, and of these active blood donors 25,396 (39.5%) were genotyped. These donors represent a valuable resource for patient treatment. This genotyping has enabled the provision of rare genotyped donor blood for patients with alloantibodies and rare reagent cells for serology.

A Prospective Observational Study To Compare Transfusion Outcomes In Abo Identical Versus Abo Non-Identical Single Donor Platelet Concentrates: An Experience From A Tertiary Healthcare Center In India

ABO incompatible single donor platelet concentrates (SDPC) have a concern about unsatisfactory increments as well as possibility of hemolytic transfusion reaction. But from Indian population no study has commented on the clinical and laboratory outcome of ABO mismatched platelet transfusion. The aim of study was to compare transfusion outcomes in ABO identical versus ABO non-identical single donor platelet concentrates. In this prospective observational study, 400 SDPC transfusions among different patients were included. In group A (n = 200), ABO identical SDPC transfusions and in group B (n = 200) ABO non-identical SDPC transfusions were added. Corrective count increment (CCI), absolute count increment (ACI), percent platelet recovery (PPR) were calculated and incidents of hemolytic transfusion reactions were noted. In group A mean ± SD of ACI, CCI and PPR were as 30.78 ± 12.51, 15.10 ± 6.677, 39948.9 ± 20099.392. In group B, mean ± SD of ACI, CCI and PPR were - 25.4 ± 15.65, 12.509 ± 5.906, 33559.2 ± 22150.304. And when CCI, ACI, PPR were compared with group A and group B, statistically significant differences were noted (p <0.05). There was statistically significant difference in CCI, ACI and PPR in oncology patients and other prophylactic recipients except patients with dengue and other infectious disease. But there was no hemolytic transfusion reaction noted in any group. Our study clearly establish the potential benefits of ABO-identical PLT transfusion. It also points out that in emergency conditions or when there is a paucity in inventory, ABO non-identical SDPC transfusion may be lifesaving and clinically significant.

What Laboratory Tests and Physiologic Triggers Should Guide the Decision to Administer a Platelet or Plasma Transfusion in Critically Ill Children and What Product Attributes Are Optimal to Guide Specific Product Selection? From the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding

OBJECTIVES

To present consensus statements and supporting literature for plasma and platelet product variables and related laboratory testing for transfusions in general critically ill children from the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding.

DESIGN

Systematic review and consensus conference of international, multidisciplinary experts in platelet and plasma transfusion management of critically ill children.

SETTING

Not applicable.

PATIENTS

Critically ill pediatric patients at risk of bleeding and receiving plasma and/or platelet transfusions.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A panel of 10 experts developed evidence-based and, when evidence was insufficient, expert-based statements for laboratory testing and blood product attributes for platelet and plasma transfusions. These statements were reviewed and ratified by the 29 Transfusion and Anemia EXpertise Initiative - Control/Avoidance of Bleeding experts. A systematic review was conducted using MEDLINE, EMBASE, and Cochrane Library databases, from inception to December 2020. Consensus was obtained using the Research and Development/University of California, Los Angeles Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method. We developed five expert consensus statements and two recommendations in answer to two questions: what laboratory tests and physiologic triggers should guide the decision to administer a platelet or plasma transfusion in critically ill children; and what product attributes are optimal to guide specific product selection?

CONCLUSIONS

The Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding program provides some guidance and expert consensus for the laboratory and blood product attributes used for decision-making for plasma and platelet transfusions in critically ill pediatric patients.

Platelet transfusion practice and platelet refractoriness for a cohort of pediatric oncology patients: A single-center study

BACKGROUND

Platelet transfusions are an essential aspect of supportive care for pediatric oncology patients. Data regarding the frequency of transfusions, pretransfusion thresholds, posttransfusion increments, and rate of platelet transfusion refractoriness (PTR) are lacking.

STUDY OBJECTIVES

(a) describe platelet transfusion practice for children with malignancy; (b) determine the normal platelet increment following platelet transfusion; and (c) assess rate of PTR.

METHODS

Inpatient pediatric oncology patients <18 years old and treated between 2009 and 2013 were identified. Data collected retrospectively included patient demographics, clinical information, laboratory values, and transfusion details.

RESULTS

Three hundred sixty-seven children were included and 144 (39%) received at least one platelet transfusion. Platelets were transfused during 25% of all inpatient admissions. The median number of platelet transfusion for any given inpatient admission was two (interquartile range [IQR]: 1-3). The median pretransfusion platelet count was 16 × 10⁹ /L and posttransfusion increment was 25 × 10⁹ /L. Most (79%) of the time, the pretransfusion platelet count was >10 × 10⁹ /L. Older children who received ABO incompatible platelet transfusions with a longer storage duration were more likely to have a poor platelet response (increment ≤ 10 × 10⁹ /L). The rate of PTR (immune and/or nonimmune) was low (8%; 11/144).

CONCLUSIONS

Practical information to parents and clinicians of newly diagnosed children regarding the likelihood and frequency of platelet transfusions was determined. The rate of PTR was low, supporting the hypothesis that children receiving leukoreduced products are at a low risk of PTR.

Neonatal and pediatric platelet transfusions: current concepts and controversies

PURPOSE OF REVIEW

In this review, we focus on three specific concepts related to platelet transfusion in the neonatal and pediatric population: choice of transfusion threshold; use of ABO-mismatched platelets; transfusion of pathogen-reduced or inactivated platelets.

RECENT FINDINGS

Recent trials support the use of lower platelet transfusion thresholds (25 000/μl) in preterm neonates, although data is limited to guide transfusion among more mature neonates. In children, there is low-level evidence as to what the prophylactic platelet transfusion threshold should be in many situations of thrombocytopenia, revealing major variability in platelet transfusion practices. Most pediatric guidelines are extrapolated from adult studies with the most evidence in treatment-associated hypoproliferative thrombocytopenia varying between a platelet transfusion threshold of 10 000/μl to 20 000/μl. Although pathogen-reduced platelets may lower the risks of transfusion-transmitted infection, the effects on platelet refractoriness and transfusion burden in this population warrant additional study.

SUMMARY

Our review highlights recent advances in neonatal and pediatric platelet transfusion and also emphasizes the urgent need for better evidence to guide practice given recent studies showing the potential harms of platelet transfusion, particularly with liberal use.

Efficacy of HLA virtual cross-matched platelet transfusions for platelet transfusion refractoriness in hematopoietic stem cell transplantation

BACKGROUND

Cross-matched platelet (cross-matched PLT) transfusion is effective for immune-mediated platelet transfusion refractoriness (PTR), but is more costly and time-consuming for physical cross-match than using standard PLT units. Recent studies have reported the utility of human leucocyte antigens (HLA) virtual cross-matched PLT (HLA-matched PLT) that is defined as HLA-A/B matched or no antibody against donor-specific antigen. Here, we evaluated the effect of HLA-matched PLTs for PTR in post hematopoietic stem cell transplant (HSCT) recipients.

STUDY DESIGN AND METHODS

Our study included a total of 241 PLTs in 16 patients who underwent HSCT at Okayama University Hospital between 2010 and 2017, receiving either HLA-matched or cross-matched PLTs. We calculated the 24-hour corrected count increments (CCI-24) to evaluate the effect of PLTs. A CCI-24 ≥ 4500 was considered to be a successful transfusion.

RESULTS

We analyzed 139 cross-matched PLTs and 102 HLA-matched PLTs. In the immune-mediated PTR, the rate of successful transfusion was 60.5% for cross-matched PLT and 63.4% for HLA-matched PLT (p = 0.825). On the other hand, the median CCI-24 for cross-matched PLT transfusions and HLA-matched PLT transfusions were 1856 and 5824 (p < 0.001), with a success rate of 28.1 and 54.1% in cases with non-immune-mediated PTR, respectively (p = 0.001).

CONCLUSION

The effectiveness of HLA-matched PLT is not inferior to cross-matched PLT. This result indicates that physical cross-match can be omitted in post HSCT PTR.

Effects of ABO Matching of Platelet Transfusions in Critically Ill Children

OBJECTIVES

To determine if transfusing ABO compatible platelets has a greater effect on incremental change in platelet count as compared to ABO incompatible platelets in critically ill children.

DESIGN

Secondary analysis of a prospective, observational study. Transfusions were classified as either ABO compatible, major incompatibility, or minor incompatibility. The primary outcome was the incremental change in platelet count. Transfusion reactions were analyzed as a secondary outcome.

SETTING

Eighty-two PICUs in 16 countries.

PATIENTS

Children (3 d to 16 yr old) were enrolled if they received a platelet transfusion during one of the predefined screening weeks.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Five-hundred three children were enrolled and had complete ABO information for both donor and recipient, as well as laboratory data. Three-hundred forty-two (68%) received ABO-identical platelets, 133 (26%) received platelets with major incompatibility, and 28 (6%) received platelets with minor incompatibility. Age, weight, proportion with mechanical ventilation or underlying oncologic diagnosis did not differ between the groups. After adjustment for transfusion dose, there was no difference in the incremental change in platelet count between the groups; the median (interquartile range) change for ABO-identical transfusions was 28 × 10 cells/L (8-68 × 10 cells/L), for transfusions with major incompatibility 26 × 10 cells/L (7-74 × 10 cells/L), and for transfusions with minor incompatibility 54 × 10 cells/L (14-81 × 10 cells/L) (p = 0.37). No differences in count increment between the groups were noted for bleeding (p = 0.92) and nonbleeding patients (p = 0.29). There were also no differences observed between the groups for any transfusion reaction (p = 0.07).

CONCLUSIONS

No differences were seen in the incremental change in platelet count nor in transfusion reactions when comparing major ABO incompatible platelet transfusions with ABO compatible transfusions in a large study of critically ill children. Studies in larger, prospectively enrolled cohorts should be performed to validate whether ABO matching for platelet transfusions in critically ill children is necessary.

Effectiveness of Pooled Platelet Transfusion in Concordant and Discordant Groups among Dengue Patients

INTRODUCTION

Dengue affects more than 50 million people per year and is one of the most common causes of severe thrombocytopaenia. Thrombocytopaenia is a common complication of dengue and other viral fevers apart from malaria, typhoid, leptospirosis, leukaemia and megaloblastic anaemia. A platelet count of <20,000/μl is characteristically seen in dengue haemorrhagic fever and dengue fever. It results from immune complex mediated platelet destruction or bone marrow suppression. Severe thrombocytopaenia <10,000/μl is one of the indications for prophylactic platelet transfusion therapy to prevent haemorrhage.

AIM

To evaluate the effectiveness of transfusion of ABO compatible and ABO incompatible pooled platelet units in severe thrombocytopaenia cases.

MATERIALS AND METHODS

In this study ABO compatible and incompatible pooled platelet units were transfused to serologically confirmed dengue cases having thrombocytopaenia with or without bleeding manifestations. Each of the adult patients received 4-6 units of pooled platelet concentrates prepared from random donor whole blood suspended in plasma for severe thrombocytopaenia. Pre and post transfusion platelet counts were compared. Children aged less than 12 years, pregnant women and patients with splenomegaly those on ayurvedic and homeopathic therapy, recipients of packed red cells on the same day of platelet transfusion and recipients of multiple platelet transfusions within 24 hours were excluded from the study.

RESULTS

The median post transfusion platelet increments (PPI) and corrected count increments (CCI) at 4hour post transfusion were 25,000/μL (5,000-80,000/μL) and 18,000/μL (range 8,000/μL- 47,500/μL) respectively among the responders. Median PPI and CCI at 24 hours were 45,000/μL and 28,863/μL among the responders. The median CCI at 4 hour post transfusion among the non-responders was 850/μL and at 24hours was 1,425/μL. At 24 hours responders showed significantly higher PPI as compared to non responders. The average platelets transfused were 4units in case of responders and 8 units in case of non-responders.

CONCLUSION

ABO identical and compatible pooled platelet transfusions were more successful in increasing the post transfusion platelet counts as compared to ABO incompatible pooled platelets.

Comparison of different platelet count thresholds to guide administration of prophylactic platelet transfusion for preventing bleeding in people with haematological disorders after myelosuppressive chemotherapy or stem cell transplantation

BACKGROUND

Platelet transfusions are used in modern clinical practice to prevent and treat bleeding in people who are thrombocytopenic due to bone marrow failure. Although considerable advances have been made in platelet transfusion therapy in the last 40 years, some areas continue to provoke debate, especially concerning the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding.This is an update of a Cochrane review first published in 2004, and previously updated in 2012 that addressed four separate questions: prophylactic versus therapeutic-only platelet transfusion policy; prophylactic platelet transfusion threshold; prophylactic platelet transfusion dose; and platelet transfusions compared to alternative treatments. This review has now been split into four smaller reviews looking at these questions individually; this review compares prophylactic platelet transfusion thresholds.

OBJECTIVES

To determine whether different platelet transfusion thresholds for administration of prophylactic platelet transfusions (platelet transfusions given to prevent bleeding) affect the efficacy and safety of prophylactic platelet transfusions in preventing bleeding in people with haematological disorders undergoing myelosuppressive chemotherapy or haematopoietic stem cell transplantation (HSCT).

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library 2015, Issue 6, 23 July 2015), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950), and ongoing trial databases to 23 July 2015.

SELECTION CRITERIA

We included RCTs involving transfusions of platelet concentrates, prepared either from individual units of whole blood or by apheresis, and given to prevent bleeding in people with haematological disorders (receiving myelosuppressive chemotherapy or undergoing HSCT) that compared different thresholds for administration of prophylactic platelet transfusions (low trigger (5 x 10(9)/L); standard trigger (10 x 10(9)/L); higher trigger (20 x 10(9)/L, 30 x 10(9)/L, 50 x 10(9)/L); or alternative platelet trigger (for example platelet mass)).

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

Three trials met our predefined inclusion criteria and were included for analysis in the review (499 participants). All three trials compared a standard trigger (10 x 10(9)/L) versus a higher trigger (20 x 10(9)/L or 30 x 10(9)/L). None of the trials compared a low trigger versus a standard trigger or an alternative platelet trigger. The trials were conducted between 1991 and 2001 and enrolled participants from fairly comparable patient populations.The original review contained four trials (658 participants); in the previous update of this review we excluded one trial (159 participants) because fewer than 80% of participants had a haematological disorder. We identified no new trials in this update of the review.Overall, the methodological quality of the studies was low across different outcomes according to GRADE methodology. None of the included studies were at low risk of bias in every domain, and all the included studies had some threats to validity.Three studies reported the number of participants with at least one clinically significant bleeding episode within 30 days from the start of the study. There was no evidence of a difference in the number of participants with a clinically significant bleeding episode between the standard and higher trigger groups (three studies; 499 participants; risk ratio (RR) 1.35, 95% confidence interval (CI) 0.95 to 1.90; low-quality evidence).One study reported the number of days with a clinically significant bleeding event (adjusted for repeated measures). There was no evidence of a difference in the number of days of bleeding per participant between the standard and higher trigger groups (one study; 255 participants; relative proportion of days with World Health Organization Grade 2 or worse bleeding (RR 1.71, 95% CI 0.84 to 3.48, P = 0.162; authors' own results; low-quality evidence).Two studies reported the number of participants with severe or life-threatening bleeding. There was no evidence of any difference in the number of participants with severe or life-threatening bleeding between a standard trigger level and a higher trigger level (two studies; 421 participants; RR 0.99, 95% CI 0.52 to 1.88; low-quality evidence).Only one study reported the time to first bleeding episode. There was no evidence of any difference in the time to the first bleeding episode between a standard trigger level and a higher trigger level (one study; 255 participants; hazard ratio 1.11, 95% CI 0.64 to 1.91; low-quality evidence).Only one study reported on all-cause mortality within 30 days from the start of the study. There was no evidence of any difference in all-cause mortality between standard and higher trigger groups (one study; 255 participants; RR 1.78, 95% CI 0.83 to 3.81; low-quality evidence).Three studies reported on the number of platelet transfusions per participant. Two studies reported on the mean number of platelet transfusions per participant. There was a significant reduction in the number of platelet transfusions per participant in the standard trigger group (two studies, mean difference -2.09, 95% CI -3.20 to -0.99; low-quality evidence).One study reported on the number of transfusion reactions. There was no evidence to demonstrate any difference in transfusion reactions between the standard and higher trigger groups (one study; 79 participants; RR 0.07, 95% CI 0.00 to 1.09).None of the studies reported on quality of life.

AUTHORS' CONCLUSIONS

In people with haematological disorders who are thrombocytopenic due to myelosuppressive chemotherapy or HSCT, we found low-quality evidence that a standard trigger level (10 x 10(9)/L) is associated with no increase in the risk of bleeding when compared to a higher trigger level (20 x 10(9)/L or 30 x 10(9)/L). There was low-quality evidence that a standard trigger level is associated with a decreased number of transfusion episodes when compared to a higher trigger level (20 x 10(9)/L or 30 x 10(9)/L).Findings from this review were based on three studies and 499 participants. Without further evidence, it is reasonable to continue with the current practice of administering prophylactic platelet transfusions using the standard trigger level (10 x 10(9)/L) in the absence of other risk factors for bleeding.

Different doses of prophylactic platelet transfusion for preventing bleeding in people with haematological disorders after myelosuppressive chemotherapy or stem cell transplantation

BACKGROUND

Platelet transfusions are used in modern clinical practice to prevent and treat bleeding in people who are thrombocytopenic due to bone marrow failure. Although considerable advances have been made in platelet transfusion therapy in the last 40 years, some areas continue to provoke debate, especially concerning the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding.This is an update of a Cochrane review first published in 2004, and updated in 2012 that addressed four separate questions: prophylactic versus therapeutic-only platelet transfusion policy; prophylactic platelet transfusion threshold; prophylactic platelet transfusion dose; and platelet transfusions compared to alternative treatments. This review has now been split into four smaller reviews; this review compares different platelet transfusion doses.

OBJECTIVES

To determine whether different doses of prophylactic platelet transfusions (platelet transfusions given to prevent bleeding) affect their efficacy and safety in preventing bleeding in people with haematological disorders undergoing myelosuppressive chemotherapy with or without haematopoietic stem cell transplantation (HSCT).

SEARCH METHODS

We searched for randomised controlled trials in the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library 2015, Issue 6), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950), and ongoing trial databases to 23 July 2015.

SELECTION CRITERIA

Randomised controlled trials involving transfusions of platelet concentrates, prepared either from individual units of whole blood or by apheresis, and given to prevent bleeding in people with malignant haematological disorders or undergoing HSCT that compared different platelet component doses (low dose 1.1 x 10(11)/m(2) ± 25%, standard dose 2.2 x 10(11)/m(2) ± 25%, high dose 4.4 x 10(11)/m(2) ± 25%).

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We included seven trials (1814 participants) in this review; six were conducted during one course of treatment (chemotherapy or HSCT).Overall the methodological quality of studies was low to moderate across different outcomes according to GRADE methodology. None of the included studies were at low risk of bias in every domain, and all the included studies had some threats to validity.Five studies reported the number of participants with at least one clinically significant bleeding episode within 30 days from the start of the study. There was no difference in the number of participants with a clinically significant bleeding episode between the low-dose and standard-dose groups (four studies; 1170 participants; risk ratio (RR) 1.04, 95% confidence interval (CI) 0.95 to 1.13; moderate-quality evidence); low-dose and high-dose groups (one study; 849 participants; RR 1.02, 95% CI 0.93 to 1.11; moderate-quality evidence); or high-dose and standard-dose groups (two studies; 951 participants; RR 1.02, 95% CI 0.93 to 1.11; moderate-quality evidence).Three studies reported the number of days with a clinically significant bleeding event per participant. There was no difference in the number of days of bleeding per participant between the low-dose and standard-dose groups (two studies; 230 participants; mean difference -0.17, 95% CI -0.51 to 0.17; low quality evidence). One study (855 participants) showed no difference in the number of days of bleeding per participant between high-dose and standard-dose groups, or between low-dose and high-dose groups (849 participants).Three studies reported the number of participants with severe or life-threatening bleeding. There was no difference in the number of participants with severe or life-threatening bleeding between a low-dose and a standard-dose platelet transfusion policy (three studies; 1059 participants; RR 1.33, 95% CI 0.91 to 1.92; low-quality evidence); low-dose and high-dose groups (one study; 849 participants; RR 1.20, 95% CI 0.82 to 1.77; low-quality evidence); or high-dose and standard-dose groups (one study; 855 participants; RR 1.11, 95% CI 0.73 to 1.68; low-quality evidence).Two studies reported the time to first bleeding episodes; we were unable to perform a meta-analysis. Both studies (959 participants) individually found that the time to first bleeding episode was either the same, or longer, in the low-dose group compared to the standard-dose group. One study (855 participants) found that the time to the first bleeding episode was the same in the high-dose group compared to the standard-dose group.Three studies reported all-cause mortality within 30 days from the start of the study. There was no difference in all-cause mortality between treatment arms (low-dose versus standard-dose: three studies; 1070 participants; RR 2.04, 95% CI 0.70 to 5.93; low-quality evidence; low-dose versus high-dose: one study; 849 participants; RR 1.33, 95% CI 0.50 to 3.54; low-quality evidence; and high-dose versus standard-dose: one study; 855 participants; RR 1.71, 95% CI 0.51 to 5.81; low-quality evidence).Six studies reported the number of platelet transfusions; we were unable to perform a meta-analysis. Two studies (959 participants) out of three (1070 participants) found that a low-dose transfusion strategy led to more transfusion episodes than a standard-dose. One study (849 participants) found that a low-dose transfusion strategy led to more transfusion episodes than a high-dose strategy. One study (855 participants) out of three (1007 participants) found no difference in the number of platelet transfusions between the high-dose and standard-dose groups.One study reported on transfusion reactions. This study's authors suggested that a high-dose platelet transfusion strategy may lead to a higher rate of transfusion-related adverse events.None of the studies reported quality-of-life.

AUTHORS' CONCLUSIONS

In haematology patients who are thrombocytopenic due to myelosuppressive chemotherapy or HSCT, we found no evidence to suggest that a low-dose platelet transfusion policy is associated with an increased bleeding risk compared to a standard-dose or high-dose policy, or that a high-dose platelet transfusion policy is associated with a decreased risk of bleeding when compared to a standard-dose policy.A low-dose platelet transfusion strategy leads to an increased number of transfusion episodes compared to a standard-dose strategy. A high-dose platelet transfusion strategy does not decrease the number of transfusion episodes per participant compared to a standard-dose regimen, and it may increase the number of transfusion-related adverse events.Findings from this review would suggest a change from current practice, with low-dose platelet transfusions used for people receiving in-patient treatment for their haematological disorder and high-dose platelet transfusion strategies not being used routinely.

A therapeutic-only versus prophylactic platelet transfusion strategy for preventing bleeding in patients with haematological disorders after myelosuppressive chemotherapy or stem cell transplantation

BACKGROUND

Platelet transfusions are used in modern clinical practice to prevent and treat bleeding in thrombocytopenic patients with bone marrow failure. Although considerable advances have been made in platelet transfusion therapy in the last 40 years, some areas continue to provoke debate, especially concerning the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding.This is an update of a Cochrane review first published in 2004 and updated in 2012 that addressed four separate questions: therapeutic-only versus prophylactic platelet transfusion policy; prophylactic platelet transfusion threshold; prophylactic platelet transfusion dose; and platelet transfusions compared to alternative treatments. We have now split this review into four smaller reviews looking at these questions individually; this review is the first part of the original review.

OBJECTIVES

To determine whether a therapeutic-only platelet transfusion policy (platelet transfusions given when patient bleeds) is as effective and safe as a prophylactic platelet transfusion policy (platelet transfusions given to prevent bleeding, usually when the platelet count falls below a given trigger level) in patients with haematological disorders undergoing myelosuppressive chemotherapy or stem cell transplantation.

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (Cochrane Library 2015, Issue 6), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950) and ongoing trial databases to 23 July 2015.

SELECTION CRITERIA

RCTs involving transfusions of platelet concentrates prepared either from individual units of whole blood or by apheresis, and given to prevent or treat bleeding in patients with malignant haematological disorders receiving myelosuppressive chemotherapy or undergoing HSCT.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We identified seven RCTs that compared therapeutic platelet transfusions to prophylactic platelet transfusions in haematology patients undergoing myelosuppressive chemotherapy or HSCT. One trial is still ongoing, leaving six trials eligible with a total of 1195 participants. These trials were conducted between 1978 and 2013 and enrolled participants from fairly comparable patient populations. We were able to critically appraise five of these studies, which contained separate data for each arm, and were unable to perform quantitative analysis on one study that did not report the numbers of participants in each treatment arm.Overall the quality of evidence per outcome was low to moderate according to the GRADE approach. None of the included studies were at low risk of bias in every domain, and all the studies identified had some threats to validity. We deemed only one study to be at low risk of bias in all domains other than blinding.Two RCTs (801 participants) reported at least one bleeding episode within 30 days of the start of the study. We were unable to perform a meta-analysis due to considerable statistical heterogeneity between studies. The statistical heterogeneity seen may relate to the different methods used in studies for the assessment and grading of bleeding. The underlying patient diagnostic and treatment categories also appeared to have some effect on bleeding risk. Individually these studies showed a similar effect, that a therapeutic-only platelet transfusion strategy was associated with an increased risk of clinically significant bleeding compared with a prophylactic platelet transfusion policy. Number of days with a clinically significant bleeding event per participant was higher in the therapeutic-only group than in the prophylactic group (one RCT; 600 participants; mean difference 0.50, 95% confidence interval (CI) 0.10 to 0.90; moderate-quality evidence). There was insufficient evidence to determine whether there was any difference in the number of participants with severe or life-threatening bleeding between a therapeutic-only transfusion policy and a prophylactic platelet transfusion policy (two RCTs; 801 participants; risk ratio (RR) 4.91, 95% CI 0.86 to 28.12; low-quality evidence). Two RCTs (801 participants) reported time to first bleeding episode. As there was considerable heterogeneity between the studies, we were unable to perform a meta-analysis. Both studies individually found that time to first bleeding episode was shorter in the therapeutic-only group compared with the prophylactic platelet transfusion group.There was insufficient evidence to determine any difference in all-cause mortality within 30 days of the start of the study using a therapeutic-only platelet transfusion policy compared with a prophylactic platelet transfusion policy (two RCTs; 629 participants). Mortality was a rare event, and therefore larger studies would be needed to establish the effect of these alternative strategies. There was a clear reduction in the number of platelet transfusions per participant in the therapeutic-only arm (two RCTs, 991 participants; standardised mean reduction of 0.50 platelet transfusions per participant, 95% CI -0.63 to -0.37; moderate-quality evidence). None of the studies reported quality of life. There was no evidence of any difference in the frequency of adverse events, such as transfusion reactions, between a therapeutic-only and prophylactic platelet transfusion policy (two RCTs; 991 participants; RR 1.02, 95% CI 0.62 to 1.68), although the confidence intervals were wide.

AUTHORS' CONCLUSIONS

We found low- to moderate-grade evidence that a therapeutic-only platelet transfusion policy is associated with increased risk of bleeding when compared with a prophylactic platelet transfusion policy in haematology patients who are thrombocytopenic due to myelosuppressive chemotherapy or HSCT. There is insufficient evidence to determine any difference in mortality rates and no evidence of any difference in adverse events between a therapeutic-only platelet transfusion policy and a prophylactic platelet transfusion policy. A therapeutic-only platelet transfusion policy is associated with a clear reduction in the number of platelet components administered.

Platelet refractoriness--practical approaches and ongoing dilemmas in patient management

Platelet refractoriness can represent a significant clinical problem that complicates the provision of platelet transfusions, is associated with adverse clinical outcomes and increases health care costs. Although it is most frequently due to non-immune platelet consumption, immunological factors are also often involved. Human leucocyte antigen (HLA) alloimmunization is the most important immune cause. Despite the fact that systematic reviews of the clinical studies evaluating different techniques for selecting HLA compatible platelets have not been powered to demonstrate improved clinical outcomes, platelet refractoriness is currently managed by the provision of HLA-matched or cross matched platelets. This review will address a practical approach to the diagnosis and management of platelet refractoriness while highlighting on-going dilemmas and knowledge gaps.

The Blood Group A Genotype Determines the Level of Expression of the Blood Group A on Platelets But Not the Anti-B Isotiter

BACKGROUND

The extent of expression of the blood group A on platelets is controversial. Further, the relation between platelets' blood group A expression and the titers of isoagglutinins has not been thoroughly investigated, so far.

METHODS

We evaluated the relation between the genotype with platelets' blood group A and H expression estimated by flow cytometry and the titers of isoagglutinins.

RESULTS

The A expression varied between genotypes and within genotypes. However, the expression in A1 was stronger than in all other genotypes (p < 0.0001). An overlap of expression levels was apparent between homozygous A1A1 and heterozygous A1 individuals. Still, The A1A1 genotype is associated with a particularly high antigen expression (p = 0.009). Platelets' A expression in A2 versus blood group O donors was also significant (p = 0.007), but there was again an overlap of expression. The secretor status had only little influence on the expression (p = 0.18). Also, isoagglutinin titers were not associated with genotypes.

CONCLUSION

To distinguish between A1 and A2 donors may reduce incompatible platelet transfusions and therefore be favorable on platelet transfusion increment. Clinical data are needed to support this notion.

Transfusion of ABO non-identical platelets does not influence the clinical outcome of patients undergoing autologous haematopoietic stem cell transplantation

BACKGROUND

There are ABO antigens on the surface of platelets, but whether ABO compatible platelets are necessary for transfusions is a matter of ongoing debate. We retrospectively reviewed the ABO matching of platelet transfusions in a subset of patients undergoing autologous haematopoietic progenitor cell transplantation during a 14-year period. Our aim was to analyse the characteristics and outcomes of patients who received platelet transfusions that were or were not ABO identical.

MATERIAL AND METHODS

We analysed 529 consecutive patients with various haematological and non-haematological diseases who underwent 553 autologous progenitor stem cell transplants at the University Hospital la Fe between January 2000 and December 2013. We retrospectively analysed and compared transfusion and clinical outcomes of patients according to the ABO match of the platelet transfusions received. The period analysed was the time from transplantation until discharge.

RESULTS

The patients received a total of 2,772 platelet concentrates, of which 2,053 (74.0%) were ABO identical and 719 (26.0%) ABO non-identical; of these latter 309 were compatible and 410 incompatible with the patients' plasma. Considering all transplants, 36 (6.5%) did not require any platelet transfusions, while in 246 (44.5%) cases, the patients were exclusively transfused with ABO identical platelets and in 47 (8.5%) cases they received only ABO non-identical platelet transfusions. The group of patients who received both ABO identical and ABO non-identical platelet transfusions had higher transfusion needs and worse clinical outcomes compared to patients who received only ABO identical or ABO non-identical platelets.

DISCUSSION

In our hospital, patients undergoing autologous haematopoietic stem cell transplantation who received ABO identical or ABO non-identical platelet transfusions had similar transfusion and clinical outcomes. The isolated fact of receiving ABO non-identical platelets did not influence morbidity or survival.

Comparison of two platelet transfusion strategies to minimize ABO-nonidentical transfusion, outdating, and shortages using a computer-simulated "virtual blood bank"

BACKGROUND

Transfusion of ABO-incompatible platelets (PLTs) is associated with reduced PLT recovery and a risk of transfusion reactions. However, a policy of transfusing only ABO-identical PLTs may increase wastage due to product outdating. A prospective study attempting to compare the effects of different ABO compatibility strategies could be costly and disruptive to a blood bank's operations.

STUDY DESIGN AND METHODS

We designed a "virtual blood bank," a stochastic computer program that models the stocking and release of products to meet demand for PLT transfusion in a simulated hospital population. ABO-nonidentical transfusions (ABOni), outdates, and inventory shortages were recorded and compared under two different transfusion strategies: ABO-First, a strategy that prioritizes transfusion of ABO-identical PLTs, and Age-First, a strategy that minimizes outdating by transfusing products closest to expiration.

RESULTS

The ABO-First strategy resulted in fewer ABOni but more outdates than the Age-First strategy. Under conditions that mimic a large hospital blood bank, the ABO-First strategy was more cost-effective overall than the Age-First strategy if avoiding an ABOni is valued at more than $19 to $26. For a small blood bank, the ABO-First strategy was more cost-effective if avoiding an ABOni is valued at more than $104 to $123.

CONCLUSION

Based on a virtual blood bank computer simulation, the cost of avoiding an ABOni using the ABO-First strategy varies greatly by size of institution. Individual blood banks must carefully consider these management strategies to determine the most cost-effective solution.

Transfusion-related adverse events in the Platelet Dose study

BACKGROUND

How platelet (PLT) product characteristics such as dose, source (whole blood derived [WBD] vs. apheresis), storage duration, and ABO matching status affect the risks of transfusion-related adverse events (TRAEs) is unclear. Similarly, more information is needed to define how recipient characteristics affect the frequency of TRAEs after PLT transfusion.

STUDY DESIGN AND METHODS

In the multicenter Platelet Dose ("PLADO") study, pediatric and adult hematology-oncology patients with hypoproliferative thrombocytopenia were randomized to receive low-dose (LD), medium-dose (MD), or high-dose (HD) PLT prophylaxis for a pretransfusion PLT count of not more than 10 × 10(9) /L. All PLT units (apheresis or WBD) were leukoreduced. Post hoc analyses of PLADO data were performed using multipredictor models.

RESULTS

A total of 5034 PLT transfusions to 1102 patients were analyzed. A TRAE occurred with 501 PLT transfusions (10.0%). The most common TRAEs were fever (6.6% of transfusions), allergic or hypersensitivity reactions (1.9%), and sinus tachycardia (1.8%). Patients assigned HD PLTs were more likely than LD or MD patients to experience any TRAE (odds ratio for HD vs. MD, 1.50; 95% confidence interval, 1.10-2.05; three-group comparison p = 0.02). PLT source and ABO matching status were not significantly related to overall TRAE risk. Compared to a patient's first PLT transfusion, subsequent PLT transfusions were less likely to have a TRAE reported, primarily due to a lower risk of allergic or hypersensitivity reactions.

CONCLUSION

The most important PLT unit characteristic associated with TRAEs was PLT dose per transfusion. HD PLTs may increase the risk of TRAEs, and LD PLTs may reduce the risk.

Transfusion efficacy of apheresis platelet concentrates irradiated at the day of transfusion is significantly superior compared to platelets irradiated in advance

BACKGROUND

Gamma irradiation is currently the standard care to avoid transfusion-associated graft-versus-host disease. Guidelines on gamma irradiation of blood components state that platelets (PLTs) can be irradiated at any stage in their 5-day storage and can thereafter be stored up to their normal shelf life of 5 days after collection. In this study, we explored whether the timing of irradiation has an effect on transfusion efficacy of apheresis PLT concentrates (APCs).

METHODS

Based on the 1-hour percent PLT recovery (PPR1h), transfusion efficacy of 1,000 eligible APCs transfused to 144 children were evaluated retrospectively. PPR1h was compared in transfused APCs irradiated at the day of transfusion and APCs irradiated in advance.

RESULTS

In univariate analysis, transfusion efficacy of APCs irradiated in advance was significantly lower than that of APCs irradiated at the day of transfusion (mean PPR1h 27.7 vs. 35.0%; p = 0.007). This was confirmed in multivariate analysis (p = 0.030). Compared to non-irradiated APCs, transfusion efficacy of APCs irradiated at the day of transfusion was not significantly inferior (mean difference -2.8%; 95% CI -6.1 to 0.5%; p = 0.092), but APCs irradiated in advance were clearly less efficient (mean difference -8.1%; 95% CI -12.2 to -4.0%; p < 0.001).

CONCLUSION

Our data strongly support that APCs should not be irradiated in advance, 1.e., ≥24 h before transfusion.

Platelet transfusion - the art and science of compromise

SUMMARY

Many modern therapies depend on platelet (PLT) transfusion support. PLTs have a 4- to 7-day shelf life and are frequently in short supply. In order to optimize the inventory PLTs are often transfused to adults without regard for ABO compatibility. Hemolytic reactions are infrequent despite the presence of 'high titer' anti-A and anti-B antibodies in some of the units. Despite the low risk for hemolysis, some centers provide only ABO identical PLTs to their recipients; this practice might have other beneficial outcomes that remain to be proven. Strategies to mitigate the risk of hemolysis and the clinical and laboratory outcomes following ABO-matched and mismatched transfusions will be discussed. Although the PLTs themselves do not carry the D antigen, a small number of RBCs are also transfused with every PLT dose. The quantity of RBCs varies by the type of PLT preparation, and even a small quantity of D+ RBCs can alloimmunize a susceptible D- host. Thus PLT units are labeled as D+/-, and most transfusion services try to prevent the transfusion of D+ PLTs to D- females of childbearing age. A similar policy for patients with hematological diseases is controversial, and the elements and mechanisms of anti-D alloimmunization will be discussed.

Prophylactic platelet transfusion for prevention of bleeding in patients with haematological disorders after chemotherapy and stem cell transplantation

BACKGROUND

Platelet transfusions are used in modern clinical practice to prevent and treat bleeding in thrombocytopenic patients with bone marrow failure. Although considerable advances have been made in platelet transfusion therapy in the last 40 years, some areas continue to provoke debate especially concerning the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding.

OBJECTIVES

To determine the most effective use of platelet transfusion for the prevention of bleeding in patients with haematological disorders undergoing chemotherapy or stem cell transplantation.

SEARCH METHODS

This is an update of a Cochrane review first published in 2004. We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL Issue 4, 2011), MEDLINE (1950 to Nov 2011), EMBASE (1980 to Nov 2011) and CINAHL (1982 to Nov 2011), using adaptations of the Cochrane RCT search filter, the UKBTS/SRI Transfusion Evidence Library, and ongoing trial databases to 10 November 2011.

SELECTION CRITERIA

RCTs involving transfusions of platelet concentrates, prepared either from individual units of whole blood or by apheresis, and given to prevent bleeding in patients with haematological disorders. Four different types of prophylactic platelet transfusion trial were included.

DATA COLLECTION AND ANALYSIS

In the original review one author initially screened all electronically derived citations and abstracts of papers, identified by the review search strategy, for relevancy. Two authors performed this task in the updated review. Two authors independently assessed the full text of all potentially relevant trials for eligibility. Two authors completed data extraction independently. We requested missing data from the original investigators as appropriate.

MAIN RESULTS

There were 18 trials that were eligible for inclusion, five of these were still ongoing.Thirteen completed published trials (2331 participants) were included for analysis in the review. The original review contained nine trials (718 participants). This updated review includes six new trials (1818 participants).Two trials (205 participants) in the original review are now excluded because fewer than 80% of participants had a haematological disorder.The four different types of prophylactic platelet transfusion trial, that were the focus of this review, were included within these thirteen trials.Three trials compared prophylactic platelet transfusions versus therapeutic-only platelet transfusions. There was no statistical difference between the number of participants with clinically significant bleeding in the therapeutic and prophylactic arms but the confidence interval was wide (RR 1.66; 95% CI 0.9 to 3.04).The time taken for a clinically significant bleed to occur was longer in the prophylactic platelet transfusion arm. There was a clear reduction in platelet transfusion usage in the therapeutic arm. There was no statistical difference between the number of participants in the therapeutic and prophylactic arms with platelet refractoriness, the only adverse event reported.Three trials compared different platelet count thresholds to trigger administration of prophylactic platelet transfusions. No statistical difference was seen in the number of participants with clinically significant bleeding (RR 1.35; 95% CI 0.95 to 1.9), however, this type of bleeding occurred on fewer days in the group of patients transfused at a higher platelet count threshold (RR 1.72; 95% CI 1.33 to 2.22).The lack of a difference seen for the number of participants with clinically significant bleeding may be due to the studies, in combination, having insufficient power to demonstrate a difference, or due to masking of the effect by a higher number of protocol violations in the groups of patients with a lower platelet count threshold. Using a lower platelet count threshold led to a significant reduction in the number of platelet transfusions used. There were no statistical differences in the number of adverse events reported between the two groups.Six trials compared different doses of prophylactic platelet transfusions. There was no evidence to suggest that using a lower platelet transfusion dose increased: the number of participants with clinically significant (WHO grade 2 or above) (RR 1.02; 95% CI 0.93 to 1.11), or life-threatening (WHO grade 4) bleeding (RR 1.87; 95% CI 0.86 to 4.08). A higher platelet transfusion dose led to a reduction in the number of platelet transfusion episodes, but an increase in total platelet utilisation. Only one adverse event, wheezing after transfusion, had a significantly higher incidence when standard and high dose transfusions were compared but this difference was not seen when low dose and high dose transfusions were compared. It is therefore likely to be a type I error (false positive).One small trial compared prophylactic platelet transfusions versus platelet-poor plasma. The risk of a significant bleed was decreased in the prophylactic platelet transfusion arm (RR 0.47; 95% CI 0.23 to 0.95) and this was statistically significant.All studies had threats to validity; the majority of these were due to methodology of the studies not being described in adequate detail.Although it was not the main focus of the review, it was interesting to note that in one of the pre-specified sub-group analyses (treatment type) two studies showed that patients receiving an autologous transplant have a lower risk of bleeding than patients receiving intensive chemotherapy or an allogeneic transplant (RR 0.73, 95% CI 0.65 to 0.82).

AUTHORS' CONCLUSIONS

These conclusions refer to the four different types of platelet transfusion trial separately. Firstly, there is no evidence that a prophylactic platelet transfusion policy prevents bleeding. Two large trials comparing a therapeutic versus prophylactic platelet transfusion strategy, that have not yet been published, should provide important new data on this comparison. Secondly, there is no evidence, at the moment, to suggest a change from the current practice of using a platelet count of 10 x 10(9)/L. However, the evidence for a platelet count threshold of 10 x 10(9)/L being equivalent to 20 x 10(9)/L is not as definitive as it would first appear and further research is required. Thirdly, platelet dose does not affect the number of patients with significant bleeding, but whether it affects number of days each patient bleeds for is as yet undetermined. There is no evidence that platelet dose affects the incidence of WHO grade 4 bleeding.Prophylactic platelet transfusions were more effective than platelet-poor plasma at preventing bleeding.

High concentration plasma-reduced plateletapheresis concentrates

Single-donor hyperconcentrated plateletapheresis (dry-platelets) collection has been introduced in the 90's as a part of the newly developed multi-component collection strategy. This approach allowed to safely collect multiple components from a single apheresis donation, i.e. RBC, FFP and/or plateletpheresis units. Dry-platelets are usually resuspended in additive solution to maintain an adequate pH during the storage period until use. Some concern existed about possible higher degrees of platelet activation in dry-platelets units when compared to standard concentration (1.0-1.6 × 10(6)/μL platelets) units and its possible correlation with lower in vivo efficiency and/or survival of the former units. Several authors investigated this specific issue, and dry-platelets units proved to be equally effective than standard concentration plateletpheresis units in recipients. The use of dry-platelets units may reduce (i) the risk of passive infusion of naturally occurring ABO-related hemolytic antibodies when donor O platelets are given to group A, B, or AB recipient, (ii) the risk of TRALI when multiparous donors undergo plateletpheresis. Furthermore, dry-platelet collection may allow for an increased amount of FFP sent to industry. Finally, hyperconcentrated platelet units may be used for "niche" indications, such as intrauterine platelet transfusion or, in case of autologous dry-platelet collection, for further freezing for long term storage in selected patients within onco-hematological settings.