ABO-incompatible platelets are associated with increased transfusion reaction rates

Platelet transfusion

PURPOSE OF REVIEW

Platelet transfusions, used as prophylaxis or treatment for bleeding, are potentially life-saving. In many countries, demand for platelet transfusion is rising. Platelets are a limited and costly resource, and it is vital that they are used appropriately. This study will explore the evidence behind platelet transfusions in different contexts, in particular recent and important research in this area.

RECENT FINDINGS

Recent randomized clinical trials demonstrate the efficacy of platelet transfusions in some contexts but potential detrimental effects in others. Platelet transfusions also carry risk of transfusion reactions, bacterial contamination and platelet transfusion refractoriness. Observational and clinical studies, which highlight approaches to mitigate these risks, will be discussed. There is growing interest in cold-stored or cryopreserved platelet units, which may improve platelet function and availability. Clinical trials also highlight the efficacy of other supportive measures such as tranexamic acid or thrombopoietin receptor agonists in patients with bleeding.

SUMMARY

Although platelet transfusions are beneficial in many patients, there remain many settings in which the optimal use of platelet transfusions is unclear, and some situations in which they may have detrimental effects. Future clinical trials are needed to determine optimal use of platelet transfusions in different patient populations.

Blood transfusion dynamics in Colombia: Unveiling patterns, reactions and survival rates in multitransfused patients

BACKGROUND AND OBJECTIVES

There is no consensus on a universally accepted threshold to categorize a patient as multitransfused. In 2019, Colombia established the definition of a multitransfused patient as someone who has received six or more blood components, irrespective of the time frame. This study aims to delineate the characteristics, adverse transfusion reactions (ATRs, definitions according to the International Society of Blood Transfusion [ISBT]) and survival rates in this population.

MATERIALS AND METHODS

We performed an analysis from the data of all institutions engaged in blood component transfusions at the national level who notified events to the National Information System of Haemovigilance (SIHEVI-INS), from January 2018 to December 2022. The selection criteria focused on individuals who not only exhibited ATRs but also received six or more blood components.

RESULTS

Among the 1,784,428 patients who received 6,637,271 blood components, an average of 3.7 components per patient was noted. Concurrently, 8378 ATRs were reported (12.6 ATRs/10,000 transfused components). Within this cohort, 691 patients met the criteria for multitransfusion. Predominantly women (51.8%), these individuals received between 6 and 14 blood components. Out of the 691 multitransfused individuals who experienced ATR, 541 had an allergic reaction. Conversely, out of the 6479 non-multitransfused individuals who experienced ATR, 3835 had an allergic reaction (odds ratio: 2.49, 95% confidence interval: 2.06-3.0). Notably, 271 multitransfused individuals (39.2%) were documented as deceased, with 76% succumbing within 12 months of encountering their most recent ATR.

CONCLUSION

Multitransfused individuals in Colombia, being a high-risk group, exhibit a heightened susceptibility to allergic reactions, surpassing the frequency observed in other transfusion populations. This underscores the necessity for tailored medical care specific to this group.

Improving platelet function following prophylactic platelet transfusion in patients with hematological malignancies

INTRODUCTION

Platelet transfusion is a standard treatment to prevent bleeding in patients with hematological malignancies. Although transfusions can improve platelet count, their impact on platelet function remains controversial.

METHODS

We conducted flow cytometry to assess platelet function before and after transfusion and performed subgroup analyses to examine differences based on blood type, corrected count increment (CCI), and platelet microparticles.

RESULTS

Overall, 50 patients who received prophylactic platelet transfusion were enrolled. CD42b expression increased, whereas CD41 expression decreased after transfusion. Apheresis platelets exhibited the lowest expression of PAC-1 and P-selectin when exposed to agonist stimulations. PAC-1 expression increased under high adenosine diphosphate (ADP) stimulation, while P-selectin expression increased under both high ADP and thrombin receptor-activating peptide stimulation. In the subgroup analysis, patients with a CCI >4500 and those with the same blood types exhibited a more significant increase in PAC-1 and P-selectin expression under agonist stimulation. When comparing apheresis platelets collected on different days, only the percentage of platelet-derived microparticles showed a significant increase.

CONCLUSION

Prophylactic transfusion improved platelet function. Platelet function significantly improved in patients with a CCI >4500, those with the same blood types as that of apheresis platelets, or those with platelet-derived microparticle levels <4.7%. No significant improvement in platelet function was noted after the transfusion of different blood types with acceptable compatibility or the transfusion of incompatible blood types. Our results suggest that transfusing platelets with the same blood type remains the optimal choice.

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.

Isohemagglutinin titration in pooled and apheresis platelets

BACKGROUND

Platelet inventory constraints necessitate ABO-incompatible platelet transfusion. Many minimize the hemolytic impact by confirming low titre (LT) donor isohemagglutinins. This process is costly. Pathogen-reduced platelets (PRP) in platelet additive solutions (PAS) will dilute plasma and decrease high-titre isohemagglutinins (HT). We determined the proportion of HT platelets and incompatible transfusions for units suspended in plasma to reassess the need for titres following introduction of PRP/PAS.

STUDY DESIGN AND METHODS

Our titre method is manual tube (1:50) dilution of platelet supernatant from apheresis or whole blood derived buffy coat pools suspended in plasma, tested with A1/B red cells. Testing included 49,058 pooled and 11,738 apheresis platelets over 4 years. The HT proportion, rate of out-of-group transfusions, and hemolytic reactions were determined. The impact of PAS dilution was estimated.

RESULTS

Totally 60,796 platelet units were tested. Group O pooled and group B apheresis platelets had HT in 6.6% and 5.7%, respectively. Group A pooled and apheresis platelets included 2% with HT. Approximately 25% of platelets transfused were ABO-incompatible and no hemolytic reactions were reported. Based on the proportions of PAS-E and plasma for PRP platelets, plasma from each donor comprises 11 mL (6% of total volume) vs 20-257 mL in untreated pools. PAS-E will replace and dilute residual plasma by at least 50%.

DISCUSSION

Rare platelet pools may demonstrate HT. PRP platelets with PAS will reduce titres and may abrogate the need for titration. A strategy of group specific transfusion or transfusion of group A PRP platelet transfusions may be a safe alternative.

The incidence of transfusion-related acute lung injury using active surveillance: A systematic review and meta-analysis

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a leading cause of transfusion-related mortality. A concern with passive surveillance to detect transfusion reactions is underreporting. Our aim was to obtain evidence-based estimates of TRALI incidence using meta-analysis of active surveillance studies and to compare these estimates with passive surveillance.

STUDY DESIGN AND METHODS

We performed a systematic review and meta-analysis of studies reporting TRALI rates. A search of Medline and Embase by a research librarian identified studies published between January 1, 1991 and January 20, 2023. Prospective and retrospective observational studies reporting TRALI by blood component (red blood cells [RBCs], platelets, or plasma) were identified and all inpatient and outpatient settings were eligible. Adult and pediatric, as well as general and specific clinical populations, were included. Platelets and plasma must have used at least one modern TRALI donor risk mitigation strategy. A random effects model estimated TRALI incidence by blood component for active and passive surveillance studies and heterogeneity was examined using meta-regression.

RESULTS

Eighty studies were included with approximately 176-million blood components transfused. RBCs had the highest number of studies (n = 66) included, followed by platelets (n = 35) and plasma (n = 34). Pooled TRALI estimates for active surveillance studies were 0.17/10,000 (95% confidence intervals [CI]: 0.03-0.43; I2  = 79%) for RBCs, 0.31/10,000 (95% CI: 0.22-0.42; I2  = <1%) for platelets, and 3.19/10,000 (95% CI: 0.09-10.66; I2  = 86%) for plasma. Studies using passive surveillance ranged from 0.02 to 0.10/10,000 among the various blood components.

DISCUSSION

In summary, these estimates may improve a quantitative understanding of TRALI risk, which is important for clinical decision-making weighing the risks and benefits of transfusion.

An outbreak of anaphylactic transfusion reactions to group B plasma and platelets and its possible relationship to Alpha-Gal syndrome

BACKGROUND

Alpha-gal syndrome (AGS) is a potentially life-threatening acquired meat allergy associated with tick bites. The allergen Galactose-α-1,3-Galactose is antigenically similar to the B blood group antigen. B blood group status offers some protection against development of the allergy. Although not preferred practice, transfusion of plasma and platelets from group B donors is believed to be safe for group O recipients.

STUDY DESIGN AND METHODS

Anaphylactic transfusion reactions were reported for three patients in two Washington DC hospitals from Nov 2022 to February 2023. A chart review was performed for all three patients. Patients or family members were interviewed, and IgE levels to alpha-gal were measured in two of the three patients.

RESULTS

One reaction was acutely fatal. All reactions were to blood group B Plasma or Platelets in blood group O recipients. One patient had two prior anaphylactic reactions to group O RBCs and group B Plasma in a previous admission. All patients came from southern Maryland where AGS is an emerging problem. Two patients had histories of tick bites, previously unexplained gastrointestinal complaints, and abnormal elevated levels of IgE to alpha gal. Two patients had cat allergies.

DISCUSSION

AGS is an emerging problem which may have implications for blood transfusion practice. Avoidance of blood group B antigen containing components may be prudent in non-blood group B patients with established AGS. Investigation for AGS should be considered in the evaluation of anaphylactic transfusion reactions.

Platelet Additive Solutions as an Alternative Storage Medium of Apheresis Platelets to Reduce ABO Antibody Titer for ABO-Incompatibility Platelet Transfusion

Introduction Platelet additive solutions (PASs) are nutrient media commonly used to replace and reduce the need for storage plasma. They are an alternative medium to maintain high-quality platelets lasting longer on the shelf for about seven days. Platelets with high titer of ABO antibody can pose a hemolytic transfusion reaction (HTR) risk if units are given across the ABO barrier. The risk of complication is greater when group O platelet is released to non-group O patients. The PAS has been known as a safe medium, where the titer of ABO antibodies is expected to be diluted. In this study, we compared the anti-A and anti-B antibody titers of apheresis platelets in PAS and non-PAS (plasma) as the suspending media. Methods A total of 20 apheresis platelet donors were selected, with seven from blood group A, eight from blood group B, and five from blood group O. The platelets were collected using an Amicus cell separator. They were suspended in PAS and plasma before being stored at a temperature range of 22-24º C. Anti-A (blood group B and O) and Anti-B (blood group A and O) antibody titers were measured and compared between the two suspending media. Wilcoxon signed-rank test is used for statistical analysis, and a p-value <0.05 is considered significant. Results The median titer of the anti-A antibody of apheresis platelets showed a significant difference between suspended in PAS (2.50) and plasma (4.00), p=0.002. Similar findings were also seen with the median titer of the anti-B antibody of apheresis platelet, in which it showed a significant difference between suspended in PAS (2.00) and plasma (4.00), p=0.004. It was observed that there was a significant reduction in both anti-A and anti-B antibody titers in the PAS as compared to the plasma group. Conclusion The decrease in ABO antibody titer in apheresis platelets stored with PAS can be beneficial for patients. This reduces the risk of HTRs if ABO-incompatible platelet units need to be issued. Thus, using PAS as a storage medium significantly improves platelet inventory management without compromising patient safety.

Acute hemolytic transfusion reaction following ABO-mismatched platelet transfusion: Two case reports

Acute hemolytic transfusion reaction following ABO-incompatible platelet transfusion: two case reports An ideal platelet transfusion should provide ABO identical platelet concentrate, and cross match compatibility is not routinely performed in the standard practices. However, ABO non identical platelet transfusions are not uncommon with the limited resources and short shelf life of platelet concentrate. Though rare, acute hemolytic transfusion reaction (AHTR) may occur following minor ABO-incompatible platelet transfusion. Here, we report two cases of thrombocytopenic patients (one child and one adult) type as Group B RhD positive and received Group O RhD positive platelet transfusions. Both patients experienced an AHTR evidenced by a drop in hemoglobin level, spherocytosis and small agglutinations on the blood film, and positive direct Coombs test. They were treated symptomatically, recovered and discharged well post-event without any morbidity. No anti-B isohemagglutinins titer were done to confirm the high titer of the antibody in the platelet donors. Our cases highlighted the importance of ABO-compatible platelet transfusion, especially to children and those vigilant groups of patients.

Severe acute haemolytic transfusion reaction secondary to a plasma incompatible group B platelet transfusion

OBJECTIVES

To report a rare case of acute hemolytic transfusion reaction (AHTR) following an ABO plasma incompatible group B platelet transfusion.

BACKGROUND

AHTR is an uncommon, but potentially fatal event. Most reported cases of platelet transfusions associated with AHTR involve group O donors.

CASE REPORT

A 34-year-old man, recipient of a group AB haploidentical haematopoietic stem cell transplantation (HSCT), had received re-induction chemotherapy for leukaemia relapse. A group B whole blood-derived buffy coat platelet pool was transfused. He developed rigours/fever, profound hemolytic anaemia, and hemodynamic instability. Serological investigations revealed AHTR from passive transfer of high titre anti-A (256 for IgM and 8192 for IgG).

DISCUSSION

This case highlights the potential risks associated with ABO-mismatched transfusions, and the complexity associated with transfusing HSCT recipients and red cell transfusion recipients with dual populations of circulating red cells. The literature on minor ABO plasma incompatible transfusions, challenges in establishing local policies to limit the risks of AHTR and risk mitigation strategies are discussed.

CONCLUSION

Clinicians must maintain a high level of suspicion for AHTR after ABO plasma incompatible platelet transfusions. Patients must be aware of the risks of AHTR, and early recognition and diagnosis of this complication may be lifesaving.

Patient ABO blood type is a major predictor of a positive DAT following a transfusion reaction

BACKGROUND

A direct antiglobulin test (DAT) checks for antibody or complement on the surface of RBCs and is often done following a transfusion reaction. While passive anti-A and anti-B antibodies are known to cause positive DATs, the extent this occurs following transfusion is unknown.

STUDY DESIGN AND METHODS

DAT results, ABO type, eluate information, and blood product information were recorded on 1097 transfusion reactions at a large academic hospital over 8 years. The effect of patient blood type, product type, and plasma compatibility of blood product transfused on DAT results were determined. Statistical significance was determined using Chi-squared testing.

RESULTS

Patient ABO blood type was a strong predictor of a positive DAT, with type O patients having 6.7% positive rate and non-O patients having a positive rate of 20.6% (p < .0001). Plasma compatibility of the product was a strong predictor of a positive DAT, with plasma compatible transfusions having a 9.4% positive rate while plasma incompatible transfusions were positive 44% of the time (p < .0001). Elution studies found that anti-A/B antibodies were the most common antibody identified. Platelets were more likely to be associated with a positive DAT when compared with RBC transfusions (p < .05).

CONCLUSIONS

These results demonstrate the patient ABO type and plasma incompatibility are strong predictors of positive DAT results following a transfusion reaction. Anti-A and anti-B antibodies are estimated to account for about 50% of positive DATs in this study.

Assessing the risks of haemolysis as an adverse reaction following the transfusion of ABO incompatible plasma-containing components - A scoping review

Background The limited supply of universal plasma has resulted in transfusion of ABO incompatible plasma to patients. As the need to implement whole blood transfusion in pre-hospitals setting rises, the lowest cut-off for anti-A/anti-B that does not cause haemolysis remains unknown. In this first scoping review, we aimed to determine the lowest ABO titre and volume reported in the literature to cause haemolysis from ABO incompatible plasma transfusions (plasma, platelets, cryoprecipitate, and whole blood). Methods We searched several databases from inception to April 2022, including all study types. Three independent reviewers extracted and reviewed the data. Primary outcome was the anti-A and anti-B titre (measured by IgM or IgG) that resulted in measurable haemolysis following ABO incompatible plasma transfusion. Results We identified 5681 citations, of which 49 studies were eligible, reporting a total of 62 cases (34 adults, 14 children and 14 did not specify age). The methods for antibody measurement and antibody type (IgG or IgM) varied significantly between studies. Component volumes were poorly reported. The most common component responsible for the haemolysis was apheresis platelets followed by pooled platelets and whole blood. Most haemolytic cases reported were due to anti-A. The lowest anti-A titre reported to cause haemolysis (children and adults) was 32 (IgG), while for anti-B it was 512 (IgG and IgM) for adults, 16,384 for paediatrics (IgG and IgM) and 128 (IgM) in cases where the age was not specified. The lowest reported volume associated with haemolysis were 100 ml (adults) and 15 ml (children). Of the 62 15 (24%) died. Conclusion The lowest titre reported to cause haemolysis was an anti-A of 32. ABO mismatch plasma transfusion may be associated with significant mortality. There is a need to agree/standardise methods for ABO titration measurement internationally for plasma components and agree the lowest anti-A/anti-B titre for transfusing ABO mismatched plasma.

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 related transfusion reactions in a large teaching hospital

BACKGROUND

Platelet transfusion practice varies widely since many aspects of platelet concentrate (PC) use have not been definitively determined. The objectives of this retrospective study were to present platelet transfusion practice and evaluate PC and patient characteristics, as well as their association with transfusion reaction (TR) rate.

MATERIAL AND METHODS

Platelet transfusions over a 5-year period were analysed regarding PC characteristics (the ABO and RhD compatibility, product type, and storage duration), patient characteristics (most responsible diagnosis, age, and gender), and TR type.

RESULTS

A total of 46,351 PCs were transfused: 76.4% whole blood-derived (WBD) and 23.6% single donor apheresis (SDA). Three thousand seven hundred seventy-six patients received platelet transfusions: 24.7% paediatric and 75.3% adult patients, 79.6% outpatients and 20.4% inpatients. As much as 63.1% of all transfused PCs were fresh (stored for≤3 days), 98.0% ABO-identical, and 87.3% of all PCs given to RhD- patients were RhD-. PCs were mainly transfused to haemato-oncology (76.8%) and cardiovascular surgery patients (6.5%). Overall, 84 (0.18%) TRs were reported, with allergic TRs (ATRs) being the most common. Although PC ABO compatibility and storage duration, as well as patient age and gender, showed differences in TR rate, only the use of PCs in platelet additive solution (PAS) showed a statistically significant reduction of TRs (P<0.001).

CONCLUSION

Transfusion practice at the University Hospital Centre Zagreb resulted in almost all patients receiving ABO and RhD identical PCs, and most of them were fresh PCs. The most important factor affecting the incidence of TRs was platelet storage solution. The use of PAS effectively reduced the rate of TRs, particularly allergic TRs.

Neonatal and pediatric blood bank practice in the United States: Results from the AABB pediatric transfusion medicine subsection survey

BACKGROUND

There are limited standards guiding the selection and processing of blood components specific for neonatal and pediatric transfusions. Therefore, blood banks (BBs) and transfusion services must create their own policies and procedures.

STUDY DESIGN AND METHODS

The American Association of Blood Banks (AABB) Pediatric Transfusion Medicine Subsection Committee developed a 74-question survey to capture neonatal and pediatric BB practices in the United States.

RESULTS

Thirty-five centers completed the survey: a response rate 15.8%. Responses indicated that most carry a mixed inventory of red blood cells (RBCs); 94.2% allow more than one type of RBC product for small-volume (SV) and large-volume (LV) transfusions to neonatal and pediatric patients. Many had storage age thresholds for RBCs transfused to neonates (SV = 60%, LV = 67.7%) but not older pediatric patients. The use of Group O for nonurgent RBC transfusion in neonates was common (74.2%). Responses related to special processing of RBCs and platelets indicated that 100% RBC and platelets are leukocyte-reduced (LR) for neonates and 97% for non-neonates. Irradiation of RBCs and platelets was commonly performed for neonatal transfusion (88.6%). Providing cytomegalovirus (CMV) seronegative products, volume reduction, and washing were variable. All centers transfused single-donor apheresis platelets; 20% allowed pathogen reduction (PR). The majority of centers have strategies limiting the amount of incompatible plasma transfused; however, few titrate ABO isoagglutinins in plasma-containing products (20% for platelets and 9.1% for plasma).

CONCLUSIONS

Variability exists in BB practice for neonatal and pediatric transfusion. Future studies are needed to understand and define best BB practices in these patient populations.

Pediatric Hemovigilance and Adverse Transfusion Reactions

Some types of transfusion reactions occur more frequently in the pediatric than the adult population. Allergic reactions are the most common, followed by nonhemolytic transfusion reactions; male children seem most susceptible to such reactions. Platelets are often implicated and pulmonary reactions are understudied in children. Clinical sequelae in neonates, such as bronchopulmonary dysplasia/chronic lung disease and intraventricular hemorrhage, have received increasing attention in relation to transfusion. There is a need to better understand the pathophysiology of transfusion reactions in neonatal and pediatric populations so preventive strategies can be undertaken. There is also a need for robust hemovigilance systems.

Does ABO and RhD matching matter for platelet transfusion?

Platelets express ABO antigens and are collected in plasma, which contains ABO antibodies as would be consistent with the donor ABO group. Platelet ABO antigens that are incompatible with recipient ABO antibodies may have accelerated clearance from circulation and result in lower count increments. ABO antibodies that are passively transferred from donor plasma may result in hemolysis of recipient red blood cells. Although platelets do not express Rh antigens, they contain small numbers of intact red blood cells or fragments, which can lead to alloimmunization in the recipient. Alloimmunization to the RhD antigen may occur when platelets obtained from RhD-positive donors are transfused to RhD-negative recipients. All of these compatibility considerations must be balanced against the available supply, which may be limited due to the 5- to 7-day shelf life of platelets. This articles describes considerations for platelet ABO and RhD selection for platelet transfusions, including the impact of major ABO incompatibility on count increments, the risks of hemolysis associated with minor ABO incompatibility, and the risk of RhD alloimmunization when RhD-negative patients receive platelets obtained from RhD-positive donors.

Comparison of ABO antibody titration, IgG subclasses and qualitative haemolysin test to reduce the risk of passive haemolysis associated with platelet transfusion

BACKGROUND

One of the strategies used to reduce the risk of haemolysis due to ABO-minor incompatible platelet transfusions is to perform a screening test to identify group O donors with high titres of anti-A and anti-B. However, critical immunoglobulin M/ immunoglobulin G (IgM/IgG) titres remain unclear.

OBJECTIVE

This study aimed to determine IgM titres of anti-A and anti-B in individual donor serum vs platelet products plasma and identify a possible association between IgM/IgG titres, haemolysin test and IgG subclasses in Brazilian blood donors from group O.

METHODS

IgM anti-A and Anti-B titration tests were performed on single-donor serum and platelet product plasma by gel agglutination (GA) at room temperature. For IgG anti-A and anti-B titration, serum was first treated with 0.01 M dithiothreitol (DTT), and the test was performed by GA with incubation at 37°C. Dilution of 1:64 as the cut-off was considered for both IgM/IgG. The qualitative haemolysin test was performed in tube, adding AB fresh serum, with incubation at 37°C. IgG subclasses were determined by GA using specific monoclonal antibodies.

RESULTS

An association between anti-A and anti-B IgM titres and haemolysin were demonstrated (P < .001). IgM titres in plasma samples from platelet components correlated to those in single-serum samples. IgG1/IgG3 subclasses were associated with total haemolysis and titres above 64, whereas IgG2/IgG4 subclasses were associated with the absence of haemolysis and titres below 64 (P < .001).

CONCLUSION

Our data suggest that a value of 64 as a critical titre can be used as a screening test of anti-A and anti-B IgM to prevent transfusion reactions. This can be a safe and cost-effective approach for managing ABO-incompatible platelet transfusions.