Evaluating safety and cost-effectiveness of platelets stored in additive solution (PAS-F) as a hemolysis risk mitigation strategy

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.

What's in Your Transfusion? A Bedside Guide to Blood Products and Their Preparation

An understanding of the contents of blood products and how they are modified before transfusion will help any physician. This article will review five basic blood products and the five most common product modifications.

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.

Hemolysin test as a tool to screen high-titer Group O platelet apheresis donors: A prospective study

BACKGROUND

Minor ABO-incompatible apheresis platelet transfusion poses a risk of hemolytic transfusion reactions in non-Group O recipients when donor's plasma possesses unusual high titers for anti-A and anti-B. The aim was to determine whether the hemolysin test can be used as a screening tool to predict high-titer Group O platelet apheresis donors.

METHODS

A prospective study, with Group O platelet donor's samples, was tested for hemolysin test and antibody titration test in parallel. Antibody titration was also performed on products suspended in platelet additive solution (PAS). Hemolysin test was assessed for diagnostic accuracy against antibody titration. Chi-square test and Mann-Whitney U-test were used to determine the relationship between the hemolysin test and antibody titration.

RESULTS

Among 107 Group O platelet donations, median anti-A and anti-B titers in donors were 32 (8-128) and 32 (4-256), respectively. High titer (≥128) for ABO antibodies was seen in 18% of donations, whereas hemolysin test was positive in 69% of donations. Hemolysin test results differ significantly with antibody titration results (P = 0.03). Hemolysin test had higher sensitivity (89%) with a strong negative predictive value (94%). None of the products suspended in PAS had high-titer antibodies.

CONCLUSION

Adopting hemolysin test as a screening tool may label a large number of units (69%) unsuitable for ABO-incompatible platelet transfusion. Alternatively identifying donors with high antibody titer or positive hemolysin test and selectively suspending their product in PAS may be a cost-effective approach and certainly prevent high-titer antibodies in the product.

Platelet components and bacterial contamination: hospital perspective 2022

Bacterial contamination of platelet units has been one of the most common transfusion-transmitted infections. Approximately 4 to 7 fatalities are being reported to the US Food and Drug Administration (FDA) annually, which cites bacterially contaminated platelet units as the cause. Over the past 3 decades, different mitigation strategies have been introduced to minimize the risk of morbidity and mortality related to contaminated platelet units. The process of platelet collection and manufacturing as well as storage at 20°C to 24°C contributes to higher prevalence of contaminated units. The risk of transfusing bacterially contaminated platelets can be lowered using different types of interventions. Prevention of bacterial contamination can be done by strict adherence to techniques that minimize contamination during unit collection. The detection of bacteria in platelet products can be improved with a combination of rapid testing and bacterial cultures that involve large volume and delayed sampling. Finally, pathogen reduction can inactivate bacteria or other pathogens present in the unit. This article describes different strategies that blood centers and transfusion services have undertaken since October 2021 to meet FDA guidance requirements. Market forces as well as feasibility of different FDA-proposed approaches have limited the number of practical solutions to just a few. In addition, the blood product availability required hospitals to adopt more progressive strategies to provide patients with needed platelet products.

Clinical and surgical outcomes of splenectomy for autoimmune hemolytic anemia

INTRODUCTION

We investigated short and long-term remission rates after splenectomy in patients with primary and secondary autoimmune hemolytic anemia (AIHA).

METHODS

All adults who underwent splenectomy for primary or secondary AIHA at a single center (2004-2018) were retrospectively reviewed. Short-term response was determined at 30-day postoperatively and long-term at one year. Complete response was defined as hemoglobin > 10 g/dL without hemolysis, transfusions, or need for additional medical therapy for > 6 months.

RESULTS

Short-term complete response was attained in 22 of 36 patients (61%), partial response in 3 (8%), no response in 11 (31%). The response rate at 1 year was complete in 14/36 (39%), partial in 14 (39%), and 8 non-response (22%). At last available follow-up (median 33.1 months (IQR 19-59), 16/37 patients had experienced a complete response (43%), 14 partial response (38%), 7 non-response (19%). 80% of partial responders with primary AIHA required maintenance therapy compared to 100% with secondary AIHA.

CONCLUSION

Splenectomy is associated with short- and long-term improvement in anemia and hemolysis in the majority of patients with AIHA. Immunosuppressants remain important supplemental therapy.

Current challenges in platelet transfusion

The supply of platelets for transfusion is a logistical challenge due to the physiology of platelets and current measures of transfusion performance dictating storage at 22°C and a short product shelf-life (<7 days). Demand for platelets has increased in recent years and changes in the demographics of the population may enhance this further. Many studies have been conducted to understand what the optimal dose and trigger for transfusion should be, mainly in hematology patients who are the largest cohort that receive platelets, mostly to prevent bleeding. Emerging data suggests that for bleeding patients, where immediate hemostasis is a key consideration, the current standard product may not be optimal. Alternative platelet preparation methods/storage options that may improve the hemostatic properties of platelets are under active development. In parallel with research into alternative platelet products that might enhance hemostasis, better measures for assessing bleeding risk and platelet efficacy are needed.

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.

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.

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.

Comparison of abo antibody levels in apheresis platelets suspended in platelet additive solution and plasma

Background

Transfusion of platelets (PLTs) with high ABO antibody titres can pose a risk of hemolysis if the unit crosses the ABO type. The PLTs stored in the platelet additive solution (PAS) remove asubstantial fraction of plasma and replace it with an isotonicbuffered solution.We aimed to assess the difference in anti-A/B antibody levels in Groups O, A and B apheresis platelets (APs) suspended in plasma and PAS.

Methodology

Apheresis donors are categorized into two groups, Plasma (Group I) and PAS (Group II), each blood group (A, B and O) had 20 samples. The anti-A/B(IgM)antibody levels were recorded from the AP donor (Group II) and from the AP units for both groups. The reduction in the anti-A/B(IgM) antibody levels in the APs suspended in the PAS for each blood group was determined.

Results

The median anti-A titres in blood Groups B (p = 0.009) and O (p = 0.005) was significantly lower in Group II. However, the difference in anti-B levels was not significant in the blood groups A (p = 0.057) and O (p = 0.205). The median level of reduction in IgM antibody titres across donor samples and the PAS-stored platelets was two-fold. The regression showed a level of reduction in antibody titres which can be explained by baseline donor antibody titres in blood groups A and B compared to blood group O.

Conclusion

The medianABO antibody titres were lower in APs suspended in PAS than in plasma. Addition of the PAS significantly lowered the IgM antibody titres by twofold, compared to plasma.