Transfusion最新文献

Background: Neonates with congenital anomalies frequently require perioperative allogeneic red blood cell (RBC) transfusion. Whole cord blood for autologous transfusion to neonates may provide an alternative RBC source, but whether sufficient volumes can be collected after delayed cord clamping to reduce allogeneic RBC requirements is unknown.

Study design and methods: Inclusion criteria were mothers delivering a viable infant >34 weeks' gestation. Sterile cord blood collection from the umbilical cord was performed at delivery as per routine obstetric indications. During storage at 4°C, we performed weekly blood gases. Blood culture, complete blood count, and hemolysis tests were performed at baseline and day 21. We compared the whole cord blood volume collected with each infant's allogeneic transfusion requirements.

Results: 54 collection attempts yielded 49 collections with a mean volume of 54.1 mL (±20.3) after median delayed cord clamping of 46 seconds (IQR 12.0, 60.0). Among 39 blood cultures obtained, 3 grew organisms after vaginal delivery (3/27, 11.0% vs. 0/12, 0% cesarean delivery, p = .54). Hemolysis was stable during storage (baseline vs. day 21, median [IQR], 0.7% [0.4%-0.9%] vs. 0.7% [0.6%-1.1%], p = .08).

Conclusions: Whole cord blood collection following delayed cord clamping was feasible, with volumes equal to 16.7 mL/kg, or one transfusion. Hemolysis was low, and although potassium increased during storage, it was consistent with patterns observed with adult donor stored whole blood. There were no positive blood cultures from collections during cesarean deliveries. Studies are needed to determine whether whole cord blood transfusions improve patient outcomes.

Background: IgG against alloantigens on transfused RBC can lead to antibody-mediated immune enhancement (AMIE). AMIE has properties not found in other forms of alloimmunization, including rapid clearance of RBCs, a requirement for Fc-gamma receptors on dendritic cells, and no dependence on IFNAR. A spleen is required for alloimmunization to transfused RBCs under normal conditions but its role in AMIE has not been assessed.

Study design and methods: Mice with surgical splenectomy or sham surgery were infused with monoclonal IgG against model antigens (HOD or KEL) followed by a transfusion of respective transgenic RBCs. Antibody binding to transfused RBCs, antigen-modulation, and RBC clearance were assessed by flow cytometry. IgM and IgG to the HOD and KEL alloantigens were quantified by flow cytometry-based crossmatch.

Results: IgG to either HOD or KEL caused brisk clearance of RBCs with almost complete antigen modulation at 24 h and a strong enhancement of both IgM and IgG in sham-operated animals. In splenectomized animals, AMIE was eliminated; antigen-modulation occurred but with decreased kinetics and magnitude; and RBC clearance was the same as in sham animals.

Conclusions: The current study extends the role of spleen as a general requirement for all known pathways of RBC alloimmunization studied thus far. However, the dissociation of clearance and antigen-modulation from AMIE shown in the current study raises the possibility that antigen-modulation and AMIE are correlated due to a confounding common cause (i.e., IgG binding RBCs).

Background: The Los Angeles Development and Rapid Operationalization of Prehospital Blood (LA-DROP) pilot will protocolize prehospital administration of low titer O-positive whole blood (LTO + WB) to patients with hemorrhagic shock in Los Angeles County (LAC). We sought to quantify the risk of death from hemolytic disease of the fetus and newborn (HDFN) associated with RhD-negative alloimmunization in females of childbearing potential (FCPs) as a result of LA-DROP.

Study design and methods: Retrospective data from LAC EMS databases were used in combination with estimates from published literature to assign probability distributions to each event in the sequence required for a transfusion of LTO + WB to result in a death from HDFN. Markov chain Monte Carlo simulation was used to derive risk estimates.

Results: We estimated that the proposed prehospital transfusion strategy would result on average in one death from HDFN for every 10,000 transfusions in the overall population (95% confidence interval [CI] 6000-25,000) and for every 1800 transfusions in FCPs (95% CI 1000-4300). Based on the projected annual volume of transfusions under LA-DROP, this would result in one death due to HDFN approximately every 26 years (95% CI 15-64).

Discussion: The estimated per-transfusion risk of HDFN is similar to previously published work from other populations. The estimated frequency of deaths from HDFN associated with LA-DROP is lower than some previously published calculations, likely because of narrower eligibility criteria for transfusion.

Background: Prior studies have evaluated transfusion recipient variables impacting red blood cell (RBC) alloimmunization, but few focused on potentially modifiable blood donor or blood component variables.

Study design and methods: Data from the Recipient Epidemiology and Donor Evaluation Study (REDS)-III, which links donor, component, and patient data in an integrated database, were accessed. For any given RBC unit with sufficient blood donor and component data, we determined if the transfusion recipient experienced a new RBC alloimmunization event ("case") within 16 weeks of the transfusion or not ("control"). Recipient diagnoses were included in the case-control matching algorithm.

Results: A total of 2676 cases were matched with 10,160 controls. In a multivariate conditional logistic regression analysis, recipients who received an RBC unit from donors with a different ABO group had a higher risk of alloimmunization (OR 1.60, 95% CI: 1.35-1.89, p < .001). Likewise, recipients who received RBCs from older donors had a higher risk of RBC alloimmunization (OR 1.01 per year of age, 95% CI: 1.00-1.01, p < .001). Irradiated RBCs were associated with a decreased risk of RBC alloimmunization in transfusion recipients (OR 0.52, 95% CI: 0.46-0.59, p < .001), though a sub-analysis of RBCs transfused to people with sickle cell disease showed no such association (p = .75). Recipients who received RBCs stored for a longer duration also had a lower risk (OR 0.99 per day of storage, 95% CI: 0.99-0.99, p < .001) of alloimmunization.

Discussion: This case-control study identified donor and component variables associated with recipient RBC alloantibody formation. Future mechanistic studies exploring these associations are warranted.

Background: Misoprostol, a synthetic prostaglandin E1 analogue, is widely used in obstetrics for its uterotonic properties. It is known to cause thermogenic side effects, a fact well-recognized in obstetrics but less familiar in transfusion medicine.

Study design and methods: Data were collected through chart review, including temperature recordings, serologic findings, and blood culture results.

Results: This case report describes a postpartum temperature spike to 39.2°C in a G1P0 female who received a red cell transfusion shortly after administration of misoprostol. Serologic workup for transfusion reaction showed no abnormalities, and blood cultures of both the patient and donor were negative for growth. Febrile nonhemolytic transfusion reaction (FNHTR) remained in the differential, however, the fever was attributed to misoprostol's thermogenic effect rather than a transfusion reaction.

Discussion: Increased awareness of misoprostol's thermogenic effects in transfusion medicine may improve differential diagnosis, reduce unnecessary testing, and enhance patient satisfaction by avoiding unwarranted concerns regarding transfusion reactions.

Background: Red blood cell (RBC) utilization in patients with sickle cell disease (SCD) in Canada is poorly defined. This study describes RBC utilization in an SCD cohort at a single Canadian center.

Study design and methods: All adults with SCD who received care at the Ottawa Hospital between January 2006 and May 2019 were included, and followed until December 2021. Data on hospital encounters and RBC transfusions were obtained from hospital databases.

Results: Overall, 273 patients were included (median age: 25 years; 53.8% female; median follow-up: 8.1 years). During the study period, there were 23,127 hospital encounters (median: 45 [interquartile range (IQR) 18, 100] per patient), with 165 patients (60.4% of cohort) receiving 22,538 RBC units. Most RBC units (86.5%) were transfused in the outpatient setting. Although only 2.9% of patients had O-negative blood type, O-negative RBC units accounted for 29.1% of units transfused. One hundred forty-seven patients received 2205 RBC units (9.8% of total) as simple transfusions (median: 5 [IQR 3, 13] per patient), and 88 patients received 20,333 RBC units (90.2% of total) during 2702 red cell exchange (RCE) sessions (median: 14.5 (IQR 1, 47.5) RCE per transfused patient). A median of 7 RBC units (IQR 6, 9) were transfused per RCE session, with a median of 30 days (IQR 28, 40) between sessions.

Discussion: Patients with SCD at our center frequently received O-negative units, and large RBC volumes were used for RCE. These results provide a utilization baseline for future education and quality improvement initiatives to optimize RBC stewardship.

Background: The XG blood group system comprises two antigens, Xg^a and CD99. CD99 is known to be carried on both the X and Y chromosomes in pseudoautosomal region 1. We identified five unrelated Japanese individuals with anti-CD99 and investigated their genomic background as well as the clinical significance of anti-CD99.

Study design and methods: Analysis of CD99 expression on RBCs and a modified monocyte monolayer assay was performed using flow cytometry. Genomic DNA was obtained from the five anti-CD99 producers to identify the deleted region responsible for the lack of CD99, and we conducted a long polymerase chain reaction using primer pairs specific for CD99 and GYG2.

Results: CD99 expression from the Y chromosome was higher than that from the X chromosome. The five anti-CD99 plasma samples gave varied agglutination strengths with the red blood cells (RBCs) expressing high and low CD99 levels, in the antiglobulin test. The phagocytosis rate of anti-CD99-sensitized RBCs was 76.6% in one case indicating a risk of hemolytic transfusion reactions (HTR), and it correlated with the level of CD99 expression. The deleted region spanned 115 kb, from CD99 exon 3 to GYG2 exon 1. All five anti-CD99 producers were homozygous for the large deletion allele.

Discussion: All five anti-CD99 producers were females with a history of pregnancy in Kyushu, Japan, and this deletion allele may thus be endemic. Our results indicated the possibility of HTR due to anti-CD99, and the risk is low when transfusing RBC products from Xg(a-) females with a low expression of CD99.

Background: Storage of platelets as platelet concentrates for transfusion is limited to 7 days in the United Kingdom due to deleterious effects on platelet quality and function that occur over time. Oxygen (O₂) availability and sufficient gaseous exchange are known to be essential in maintaining the viability and function of platelets stored for transfusion. Despite this, there is a paucity of studies undertaking direct measures of O₂ and optimization of conditions throughout storage. We address this and modulate the storage conditions to improve platelet quality and function.

Study design and methods: Electron paramagnetic resonance oximetry was implemented to directly measure the [O₂] experienced by stored platelet concentrates and the O₂ consumption rate under standard blood banking conditions. From these direct measures the mathematical modeling was then applied to predict the main parameters contributing to effective O₂ distribution throughout the unit.

Results: This study demonstrates reducing the storage [O₂] to reflect near physiological levels significantly alters O₂ distribution within the unit and negatively impacts platelet functionality and quality, and therefore is not a viable storage option.

Discussion: We show the reduction of platelet concentration within a unit improves O₂ availability and pH, promotes a more uniform distribution of O₂ throughout prolonged storage, and maintains platelet agonist-induced aggregation comparable to 100% platelet concentration. This may be a viable option and could potentially lead to reduced donor demand.

Background: Storage of packed red blood cells (RBCs) for transfusion leads to biochemical and morphological changes, increasing hemolysis risk. Urate levels in blood bags at donation contribute to the molecular heterogeneity and hemolytic propensity of stored RBCs. However, studies to date have been underpowered to investigate at scale the contribution of donor demographics and genetics to the heterogeneity in urate levels across donations.

Study design and methods: Urate levels were measured in 13,091 RBC units from the REDS study. Characteristics tested included hemolysis parameters (spontaneous, osmotic, oxidative) at storage end and post-transfusion hemoglobin (Hb) increments in recipients. Donor demographics, urate levels, and genetic variants were analyzed for associations with these outcomes.

Results: Elevated urate levels were linked to male sex, older age, high BMI, and Asian descent. Units with high urate levels exhibited increased spontaneous and osmotic hemolysis, while oxidative hemolysis was unaffected. Genetic variants in SLC2A9 (V282I) and ABCG2 (Q141K) were strongly associated with elevated urate, particularly in Asian donors. Post-transfusion analyses revealed that units from female donors carrying these variants were associated with reduced Hb increments, with up to a 31% reduction in efficacy. This effect was not observed in male donors.

Discussion: RBC urate levels and genetic traits significantly impact storage quality and transfusion outcomes. These findings highlight the importance of donor molecular characteristics for optimizing transfusion strategies. Moreover, genetic and metabolic insights may inform donor recruitment efforts, providing health feedback to volunteers while ensuring effective transfusion products.