Apheresis platelet transfusions: does ABO matter?

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.

Immunoglobulin M anti-A and anti-B titers in South Texas group O D+ male donors

BACKGROUND

The success of whole blood (WB) in damage control resuscitation on the battlefield has generated interest in its use for civilian trauma. Blood centers must maintain a committed donor pool with low isoagglutinin titers to provide this product. Information regarding isoagglutinin titers in different donor populations will help with targeted recruitment of these donors.

STUDY DESIGN AND METHODS

Sequential O D+ male donors with a history of two or more donations at a fixed site were tested for immunoglobulin (Ig)M anti-A and anti-B using a single titer cutoff of 256. Donors testing negative at this cutoff were considered "low titer" while positive donors were considered "high titer." Age and self-identified race/ethnicity were retrospectively obtained from the blood establishment computer system. Fisher's exact analysis was used for statistical analysis with a p value of less than 0.05 considered significant.

RESULTS

Of 3274 donors, 426 tested as high titer, while 2848 tested as low titer. The data show an association of donor age and prevalence of high titers with older age groups showing a lower prevalence of high titers. In addition, different races/ethnicities have different prevalences of high titers with the Caucasian/white group showing a lower prevalence of high-titer donors versus the Hispanic and undeclared race groups.

CONCLUSION

The prevalence of high-titer IgM anti-A or -B donors varies by age group and race/ethnicity in our data set. This information will provide information on what donor groups to target for collection of low-titer O WB.

Evaluation of Magnetized-Erythrocyte Group Antigens to Detect ABO Antibodies

Screening for IgM titers of anti-A and anti-B is recommended when providing ABO incompatible platelet transfusion. The life-time of reagent cells depends upon the preservative diluents. We aimed to evaluate the IgM titers of anti-A and anti-B testing with magnetized-erythrocyte group antigens (MEGA) and fresh RBCs and study the relationship of ABO antibody titers between both techniques. Altogether, 100 serum samples from group O donors at the National Blood Centre, Thai Red Cross Society, Bangkok, Thailand were included. EDTA blood from three different A and B blood group individuals was prepared as fresh reagent RBCs and MEGA. Each serum sample was tested simultaneously for IgM anti-A and anti-B titers using fresh RBCs and MEGA by standard tube technique. Antibody titers were compared between both techniques. Test for reproducibility and stability of MEGA were performed. The IgM anti-A and anti-B titers using fresh RBCs yielded higher agglutination scores than MEGA (P < 0.001). However, a good correlation was obtained in the agglutination titers (anti-A, r = 0.838 and anti-B, r = 0.877). The mean and standard deviation of anti-A and anti-B titers using MEGA from five sera in triplicate showed no significant difference (P > 0.05). Moreover, the titer test results using MEGA after dilution remained stable up to 8 h. The MEGA can be used as a replacement for fresh RBCs to perform ABO serum grouping. It is simple to use, avoids centrifugation and provides good results in terms of stability and reproducibility.

The characteristics of ABO antibodies in group O Thai blood donors

This study aimed to characterize anti-A and anti-B hemolysins, IgM, and IgG titers in Thai blood donors. Altogether, 300 serum samples from group O donors at the National Blood Centre, Thai Red Cross Society, were screened for anti-A and anti-B hemolysins and treated with 0.01 M dithiothreitol to characterize IgM and IgG titers by standard tube technique. Antibody titers were compared with hemolysis grade. Male and female ratio = 1:1.3 and ages ranged from 17 to 60 years. The overall prevalence of anti-A and anti-B hemolysins was 69%. Anti-A and anti-B hemolysins comprised 18.3% and 16.7%, respectively and 34% had both antibodies. High titers of anti-A hemolysins were associated with females (P< 0.05), and only anti-B IgM titers were associated with age (P< 0.05). Interestingly, the association of anti-A IgM titers, anti-A IgG titers, and hemolysin grade was demonstrated (P< 0.05). A significant association between hemolysin grade and anti-B IgM titers was found (P< 0.05). The prevalence of anti-A and anti-B hemolysins and high titers of IgM and IgG in Thais are high. Hemolysin grade showed significant associations with IgM titers; therefore, when providing ABO-incompatible platelet transfusion, especially for female plateletpheresis donors, IgM high titers of anti-A and anti-B screening is suggested.

Facteurs influençant le rendement transfusionnel plaquettaire « une interdépendance entre le patient et le produit »

A great variety of patient- and product-related factors influence the outcome of platelet transfusions. The patient-related factors are numerous, either physical factors as weight and height, or related to pathological being as splenomegaly, fever, infection, disseminated intravascular coagulation, previous HLA allo-immunization, or related to the treatment, as amphotericin. Major platelet factors that are associated with impaired responses are giving a decreased dose of platelets, ABO incompatible products, and platelets stored for more than 48 hours. When trying to prevent or to treat refractoriness and to finely tune platelet transfusions, all these factors have to be taken into account, and a good coordination between the blood bank and the clinician team is essential.

Factors affecting platelet yield and their impact on the platelet increment of patients receiving single donor PLT transfusion

The aim of this study was to analyze the impact of various donor and machine parameters on PLT yield in 127 PLT apheresis procedures, to optimize PLT yield achieving clinical and economic advantages. One hundred and twenty-seven apheresis procedures were analyzed. Age, gender, volume processed, Hb, and PLT precounts were included as donor predicting variables. AC infusion rate, processing time, and plasma volume collected with PLTs were assessed as machine parameters. We evaluated the post-transfusion effectiveness in 23 patients with thrombocytopenia, studying the effect of PLT dose, ABO group, and PLT storage time. Females gave higher yields, compared to males, P<0.01. PLT yield correlated positively with PLT precount (r=0.512), and TBV (r=0.404), and negatively with donor preapheresis Hb (r=-0.306). Processing time and AC infusion rate had a positive impact on PLT yield. Post-apheresis decrease in PLT count was 53.6+/-26.3x10(11). Donors with Hb>or=12 g/dl, donated safely. Most of the complications were citrate related (13.4% of all procedures). PLT increments in transfused patients correlated positively with the number of units transfused (r=0.41), and negatively with PLT storage days (r=-0.342). PLT increments in patients receiving ABO-compatible PLTs were 75% higher, compared to the increments in patients receiving incompatible PLTs. PLT count and volume processed were the main predictors of PLT yield. Increasing the processing time, the AC infusion rate, or the volume of plasma obtained with PLTs can increase PLT yields. High PLT dose, short storage time, as well as ABO compatibility should be considered during PLT transfusion.

Acute hemolytic transfusion reaction in a pediatric patient following transfusion of apheresis platelets

The practice of transfusing ABO-incompatible platelets, driven primarily by concerns about inventory management, has been considered generally safe because the accompanying plasma is usually diluted in the recipient's total blood volume. However, if the platelet product contains a large volume of plasma or a high concentration of incompatible isoagglutinin, there may be hemolysis of the recipient's red cells. Patients with a small blood volume, such as babies and children, are considered to be at particular risk for such a complication. We describe the case of a baby who suffered massive hemolysis of her group A red cells after transfusion of group O Apheresis Platelets containing a high-titered anti-A isoagglutinin. We also offer a review of the literature on this subject and recommendations to avoid acute hemolytic reactions as a result of platelet transfusion.