ABO Non-identical Transfusions Research Articles

Use of O RhD-negative red blood cells: A nationwide, prospective audit.

Despite declining transfusion rates, overuse of O RhD-negative red blood cells (RBCs) risks the secure supply of this limited resource. A nationwide prospective audit was performed in Finland to understand the clinical use and inventory management of O RhD-negative units. Our aim was to identify areas where policy changes could help alleviate the shortage of O RhD-negative RBCs. The use of every O RhD-negative unit in Finland during a period of 1 month was reviewed. For each issued unit (n= 1105), unit age, urgency of transfusion, hospital and patient demographics, and specific reasons for issuing O RhD-negative units were recorded. Almost half of the O RhD-negative units (n= 529, 47.9%) were issued to non-O RhD-negative patients. Only 22.3% (n= 118) were issued for females under the age of 50. Of the units for ABO-nonidentical transfusion, one-third (32.5%, n= 172) were issued for emergency transfusion, two-thirds (67.5%, n= 357) for non-urgent transfusions. The most common reason for issuing an O RhD-negative unit was inventory management (n= 172, 48.2% of units issued for non-urgent transfusion). Most of these units were issued close to the unit expiry date. This nationwide audit revealed that a significant proportion of O RhD-negative RBCs are used inappropriately. Clinicians should be educated on the appropriate use of O RhD-negative RBCs, and blood banks should develop strategies for inventory management to avoid issuing O RhD-negative units purely to prevent outdating.

Necrotizing enterocolitis and mortality after transfusion of ABO non-identical blood.

The relationship between ABO non-identical transfusion and the outcomes of necrotizing enterocolitis (NEC), and all-cause mortality in very-low birth weight (VLBW) neonates receiving red blood cell transfusion is unknown. A retrospective multicenter cohort study was conducted in VLBW neonates in neonatal intensive care units between 2004 and 2016. VLBW (≤1500 grams) neonates were followed until discharge or in-hospital death. The primary exposure was ABO group. Secondary exposures included platelet count, plasma transfusions, and maternal ABO group. Outcome measures were NEC (defined as Bell stage ≥ 2) and all-cause mortality. Time-dependent Cox regression models with competing risks were used to investigate factors associated with NEC and mortality. Thousand and sixteen neonates were included with 10.8% developing NEC (n=110) and 14.1% mortality (n=143). Platelet count (hazard ratio [HR]=0.995; 95% confidence interval [CI]: 0.922-0.998) and number of plasma transfusions (HR=2.908; 95% CI:1.265-6.682) were associated with NEC, while ABO group (non-O vs. O) was not (HR=0.761; 95% CI: 0.393-1.471). Higher all-cause mortality occurred in neonates without NEC who were non-O compared with O (HR=17.5; 95% CI: 1.784-171.692), but not in neonates with NEC (HR=1.112; 95% CI: 0.142-8.841). Plasma transfusion was associated with increased mortality in both groups. ABO non-identical transfusion was not associated with NEC or mortality in neonates with NEC. It was associated with increased mortality in neonates without NEC. As many neonatal intensive care units transfuse only O group blood as routine practice, future trials are needed to investigate the association between this practice and neonatal mortality.

The Effect of ABO Immune Complexes on Endothelial Cell Integrity As Measured By Electric Cell-Substrate Impedance Sensing (ECIS) and Confocal Microscopy

Background: ABO non-identical transfusions have been associated with increased risk of hemolytic transfusion reactions. We previously reported that the ABO immune complexes (ABO-IC) formed in vitro as a result of ABO non-identical exposure affect platelet function, red blood cell integrity, and clot kinetics (Vox Sang. 2016;110:219-26). We developed an in vitro model as a means to investigate the interaction between ABO-IC and endothelial cells (EC).Methods: The ABO-IC were prepared by combining equal volumes of concentrated O plasma (high titers of anti-A and anti-B) with A plasma (high concentration of A antigens). Anti-A titers were measured before and after mixing to confirm the presence of ABO-IC. ABO-known human pulmonary vessel EC were then seeded onto gold microarray plates to prepare for electric cell-substrate impedance sensing (ECIS). The trans-endothelial electrical resistance (TER) was recorded for 48 hours after the addition of media, PBS, thrombin, O, A, B, and/or AB plasmas added 1:1 with media, as well as various concentrations of ABO-IC. Statistics were performed using the chi-square test to compare TER values at various timepoints to baseline. Human pulmonary EC were cultured on glass-bottomed petri dishes for confocal microscopy. The cells were stained with fluorescent green calcein AM dye and assessed for viability at 100x magnification at baseline and again 15 minutes following the addition of ABO-IC.Results: Substantial decreases in TER were observed over the course of 2 hours in O and A EC when treated with non-identical plasma, and sustained over 10 hours (p<0.05 for all). Significant decreases in TER were also observed in cells treated with various concentrations of ABO-IC, over 2 hours and were found to be dose-dependent and independent of ABO type (p<0.05 for all). Unlike the ABO-IC, exposure to thrombin revealed a marked decrease in TER after 2 hours, although the final TER measurement revealed complete recovery (Table 1a-c). Incubation with ABO-identical plasma showed slight decreases in TER over time that were not statistically significant when compared to incubation with cell media (Figure 1a-b). Physical damage to the EC membrane were observed via confocal microscopy after 15 minutes of exposure to ABO-IC (Figures 2a-b).Discussion: The exposure of ABO-IC to human pulmonary vessel EC revealed significantly decreased monolayer integrity via ECIS and confocal microscopy. The decreases seen in the TER of EC incubated with non-identical plasma and ABO-IC indicate the potential for capillary leak as a possible reaction to ABO non-identical transfusion. We have shown that the substantial decrease in TER when exposed to plasma is ABO type-dependent, and that the damage caused to the cells happens within a few hours and is irreversible over 48 hours. The confocal images reveal a significant change in the morphology of the EC membrane within 15 minutes of exposure to ABO-IC. These preliminary data suggest that anti-A and ABO-IC may significantly affect EC viability and function. This in vitro model provides potential novel mechanisms for the detrimental effects of ABO non-identical transfusion on EC. Further investigation of biomarkers for cell viability and integrity in response to exposure to ABO-IC is underway. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Is It Time to Reconsider the Concepts of "Universal Donor" and "ABO Compatible" Transfusions?

Is It Time to Reconsider the Concepts of "Universal Donor" and "ABO Compatible" Transfusions?

ABO-immune complex formation and impact on platelet function, red cell structural integrity and haemostasis: an in vitro model of ABO non-identical transfusion.

Transfusion of ABO non-identical platelets has been associated with fatal haemolytic reactions, increased red cell transfusion needs and other adverse effects, but the practice of ABO matching in platelet transfusion is controversial. Immune complexes can be formed from the anti-A and/or anti-B antibodies and ABO soluble antigen(s) present in donor and recipient plasma after ABO non-identical transfusions. We hypothesized that these immune complexes affect recipient red cell structural integrity, platelet function and haemostasis. Haemolysis, platelet function and haemostatic function were assessed before and after incubation of recipient red cells, platelets and whole blood with normal saline controls, ABO-identical plasma controls or in vitro-generated ABO-immune complexes. ABO-immune complexes caused significantly increased haemolysis (P < 0·001), inhibition of platelet function (P = 0·001) and disruption of clot formation kinetics (P < 0·005) in both group A and O recipient samples. Substantial changes in platelet function, red cell integrity and haemostasis occur after in vitro exposure to immune complexes. These in vitro findings may explain, in part, previously observed associations of ABO non-identical platelet transfusions with adverse effects including increased red cell transfusion needs, organ failure and mortality.

Alterations of platelet function and clot formation kinetics after in vitro exposure to anti‐A and ‐B

ABO-mismatched platelets (PLTs) are commonly transfused despite reported complications. We hypothesized that because PLTs possess A and B antigens on their surface, ABO-mismatched transfused or recipient PLTs could become activated and/or dysfunctional after exposure to anti-A or -B in the transfused or recipient plasma. We present here in vitro modeling data on the functional effects of exposure of PLTs to ABO antibodies. PLT functions of normal PLTs of all ABO types were assessed before and after incubation with normal saline, ABO-identical plasma samples, or O plasma samples with varying titers of anti-A and anti-B (anti-A/B). Assays used for this assessment include PLT aggregation, clot kinetics, thrombin generation, PLT cytoskeletal function, and mediator release. Exposure of antigen-bearing PLTs to O plasma with moderate to high titers of anti-A/B significantly inhibits aggregation, prolongs PFA-100 epinephrine closure time, disrupts clot formation kinetics, accelerates thrombin generation, reduces total thrombin production, alters PLT cytoskeletal function, and influences proinflammatory and prothrombotic mediator release. Our findings demonstrate a wide range of effects that anti-A/B have on PLT function, clot formation, thrombin generation, PLT cytoskeletal function, and mediator release. These data provide potential explanations for clinical observations of increased red blood cell utilization in trauma and surgical patients receiving ABO-nonidentical blood products. Impaired hemostasis caused by anti-A/B interacting with A and B antigens on PLTs, soluble proteins, and perhaps even endothelial cells is a potential contributing factor to hemorrhage in patients receiving larger volumes of ABO-nonidentical transfusions.

The Effects of Anti-A and Anti-B On Platelet Function: An in Vitro Model of ABO Non-Identical Transfusion.

Abstract 2120Poster Board II-97Background: Transfusion of ABO non-identical red blood cells (RBCs) can cause immune mediated hemolytic transfusion reactions. Therefore, only ABO identical RBCs are transfused, except in emergencies, when group O RBCs are transfused. Use of exclusively ABO identical plasma and platelet (PLT) transfusions is not uniformly practiced nor always feasible despite reports of hemolytic reactions. Since PLTs and soluble plasma proteins possess A and B antigens, ABO non-identical PLTs could, theoretically, be activated and/or rendered hypofunctional by anti-A and anti-B antibodies (Abs) in transfused or recipient plasma. Recent findings demonstrate that transfusion of ABO non-identical PLTs is associated with increased bleeding in surgical patients and patients with leukemia. Blunt trauma patients who received at least one ABO non-identical blood product transfusion demonstrated a significantly higher RBC usage (12.3 ± 6.9 SD versus 8.4 ± 9.9 SD, p-value 0.0011) compared to those patients who received only ABO identical transfusions (Transfusion. 2007;47:192A). ABO identical PLT transfusions in leukemia patients were a significant predictor of survival (Leukemia. 2008;22:631-5). In a multi center retrospective analysis of more than one million cancer patients over a period of 9 years, Khorana et al. demonstrated an overall venous thromboembolism (VTE) rate of 4.1%. In multivariate risk factor analysis, the association between blood transfusions and VTE had an odds ratio of 1.35 (1.31-1.39, 95% CI) with a p value of < 0.001 (Arch Intern Med. 2008;168:2377-81). We hypothesized that PLTs activated by ABO Abs might have altered function. Methods and Materials: PLT function was evaluated by testing aggregation in platelet rich plasma (PRP). Aggregation was performed with PRP from 7 type A and 6 type B normal blood donors following a 10 min incubation period at 37°C with either normal saline, group O or AB plasma. PLTs were activated by 20 mM ADP and aggregation quantitated from the maximum change in OD. Similar experiments were repeated utilizing different titration of the commercial anti-A and anti-B anti-sera. Results: Following incubation with O plasma, PLT aggregation was inhibited by a mean of 38% and 18% for group A and B PLTs, respectively (P ≤ 0.005) (Figure). A trend toward inhibition was observed when type A PLTs were incubated with control AB plasma (average of 14%, P = 0.187), whereas type B PLT showed no inhibition when incubated with AB plasma (P = 0.939) (Table 1). PLT aggregation with the anti-sera showed gradual inhibition correlated with the antibody titer (Table 2). Conclusion: Mediators in group O plasma, most likely anti-A and anti-B Abs, cause impaired PLT aggregation in ABO non-identical PLTs. These in vitro findings may explain, at least in part, clinical observations that patients receiving ABO non-identical PLT transfusions experience more bleeding than recipients of ABO identical PLT transfusions.Table 1:PLT aggregation of A and B PRP with saline, O and AB plasma.Blood Donor TypeNAverage Percentage of Platelet Aggregation (SD)Normal Saline“O” PlasmaP value*“AB” PlasmaP valueA792 (7.4)54 (9.9)< 0.00578 (2.9)0.187B685 (6.8)67 (9.8)0.00585.3 (7.9)0.939P value < 0.05 is considered statistically significant. [Display omitted] Table 2:PLT aggregation of A and B PRP with different titration of the commercial anti-A and anti-B anti-sera.Anti-sera/PlasmaType A PRPP valueType B PRPP valueBaseline93.7 (3.1)—83.4 (11)—1:102448.7 (8.5)0.00636.3 (7.8)0.00051:51257.3 (2.5)0.000147.7 (7.5)0.0021:25659.5 (3.5)0.00859.5 (0.7)0.0021:12855.5 (3.5)0.00667 (2.8)0.027AB plasma87.7 (3.2)0.0881.2 (16)0.88 Disclosures:No relevant conflicts of interest to declare.

Blood Group O and ABO Non-Identical Platelet Transfusions Are Associated with Increased Red Cell Utilization in Non-Trauma Surgical Patients.

The transfusion of ABO non-identical platelets is an accepted practice, involving infusion of antigen and/or antibody that is ABO incompatible with the recipient. This results in the formation of high molecular weight immune complexes, which could, in theory, adversely affect platelet and coagulation factor function. Studies have demonstrated putative deleterious effects of ABO non-identical transfusions. In cardiac surgery patients receiving ABO non-identical platelets required 50% more red blood cell (RBC) transfusions than those who received only ABO identical platelets (Transfusion 41:790, 2001). Furthermore, blood group O and A patients have genetically determined lower levels of von Willebrand factor (vWF) than B and AB patients (Blood 69:1691, 1987), and might be expected to have more bleeding and require more RBC transfusions. Our institution implemented a protocol of transfusing only ABO identical components in April, 2005. We report here the potential effects of transfusing ABO non-identical platelets, by comparing RBC usage in surgical patients before and after introduction of a protocol of “only ABO identical” transfusions. We also report the role of ABO blood group in red cell usage. Because non-group O trauma patients by necessity receive group O red cells we excluded them from this analysis. Transfusion records for all non-trauma surgical patients receiving any platelet transfusions for one year after April, 2005 were reviewed. Patients receiving only ABO identical platelet transfusions were analyzed by blood groups: B/AB versus O/A. Group B/AB patients (n=72) required a mean of 12.5 +/− 11.7 RBCs, whereas group A/O patients (n=313) required 17.8 +/− 20.5 (p=0.036). These findings are the reverse of the patient populations receiving a mixture of ABO identical and non-identical platelets prior to April, 2005, before the implementation of an “ only ABO identical” transfusion policy. Group B/AB patients, who received more ABO non-identical platelet transfusions than A/O patients (mean 7.5 +/− 11 versus 3.3 +/− 6.2, p=0.0001), required significantly more RBCs (mean 19 +/− 25 versus 13 +/− 13, p=0.0086). Amongst those receiving only ABO identical transfusions group O patients required the largest number of RBCs, (mean 19.6 +/− 24.1), followed by A (16.0 +/− 15.8, p=0.096), B (13.2 +/− 13.1, p=0.041), and AB (11.2 +/− 7.8, p=0.05). One plausible explanation is that blood group O patients have the lowest levels of vWF and other clotting factors, while AB patients have the highest levels (AB > B > A > O). Our data in recipients of ABO identical transfusions confirm findings in the literature that group O patients may be at greater risk of hemorrhage than groups B and AB patients. However, when ABO non-identical platelets are transfused, significantly more bleeding is seen in group AB and B patients than in group O patients. We hypothesize that ABO non-identical transfusions may impair, rather than improve, hemostasis in some patients.RBC Usage (Units) Pre and Post ABO Identical Only PolicyBlood Groups A/OBlood Groups B/ABP-ValuePre-ABO Identical Only Policy13 +/− 1319 +/− 250.0086Post-ABO Identical Only Policy17.8 +/− 20.512.5 +/− 11.70.036

ABO and platelet transfusion revisited

Historically, ABO compatibility between donor and recipient has been considered of minor importance for platelet transfusion. However, in a recent randomized trial we showed that provision of only ABO-identical platelets was associated with a significantly higher corrected count increment (CCI) in the early transfusions and with a twofold reduction in refractoriness, as compared with platelets given unmatched for ABO. In older studies this phenomenon was not observed. We wondered whether in these previous studies the use of the conventional term "ABO compatible", whereby ABO-identical platelet transfusions are grouped with those that are merely ABO compatible, might have obscured the advantages of the ABO-identical platelets. In this paper the CCI from our original study are compared with what would have been found had the conventional terminology of "ABO compatible" and "ABO incompatible" been used. In our original study the mean CCI in patients receiving only ABO-identical platelets was 64% higher than that achieved with ABO-unmatched products. However, when the transfusions were reanalyzed according to conventional terminology of ABO "compatible" and "incompatible," the actual benefits of ABO-identical platelets were no longer detected. Thus, had we used the conventional terminology in the original study we would have come to completely different conclusions about the importance of ABO in platelet transfusion. We hypothesize that transfusion of ABO-incompatible plasma leads to the formation of immune complexes that can destroy compatible platelets by indirect mechanisms. This model predicts that the success of a transfusion could be affected by previous incompatible transfusions. When transfusions were classified as to whether they were first, second, or third unmatched transfusion, increasing numbers of transfusions of ABO-incompatible plasma were associated with progressively poorer mean increments. The same was true for platelet ABO-incompatible transfusions. In contrast, increasing numbers of ABO-identical transfusions were not associated with poorer increments. The failure to appreciate that (a) transfusions containing ABO-incompatible plasma yield poor increments and (b) the effects of ABO-nonidentical transfusions are cumulative, and therefore affect the success of subsequent identical transfusions, may have led in the past to the incorrect conclusion that ABO matching was of minor importance in repetitively transfused patients.