Stored red blood cells (RBCs) undergo progressive deleterious functional, biochemical, and structural changes. The mechanisms responsible for the adverse effects of transfusing stored RBCs remain incompletely elucidated.
STUDY DESIGN AND METHODS
Awake wild-type (WT) mice, WT mice fed a high-fat diet (HFD-fed WT) for 4 to 6 weeks, and diabetic (db/db) mice were transfused with syngeneic leukoreduced RBCs or supernatant with or without oxidation (10% of total blood volume) after storage for not more than 24 hours (FRBCs) or 2 weeks (SRBCs). Inhaled nitric oxide (NO) at 80 parts per million was administered to a group of mice transfused with SRBCs. Blood and tissue samples were collected 2 hours after transfusion to measure iron and cytokine levels.
SRBCs had altered RBC morphology and a reduced P50. Transfusion of SRBCs into WT or HFD-fed WT mice did not produce systemic hemodynamic changes. In contrast, transfusion of SRBCs or supernatant from SRBCs into db/db mice induced systemic hypertension that was prevented by concurrent inhalation of NO. Infusion of washed SRBCs or oxidized SRBC supernatant into db/db mice did not induce hypertension. Two hours after SRBC transfusion, plasma hemoglobin (Hb), interleukin-6, and serum iron levels were increased.
Transfusion of syngeneic SRBCs or the supernatant from SRBCs produces systemic hypertension and vasoconstriction in db/db mice. It is likely that RBC storage, by causing in vitro hemolysis and posttransfusion hemoglobinemia, produces sustained NO scavenging and vasoconstriction in mice with endothelial dysfunction. Vasoconstriction is prevented by oxidizing the supernatant of SRBCs or breathing NO during SRBC transfusion.
Cellular therapy studies are often conducted at multiple clinical sites in order to accrue larger patient numbers. In many cases this necessitates use of localized Good Manufacturing Practices (GMP) facilities to supply the cells. To assure consistent quality, oversight by a quality assurance group is advisable. In this study we report the findings of such a group established as part of the Cardiovascular Cell Therapy Research Network (CCTRN) studies involving use of autologous bone marrow mononuclear cells (ABMMC) to treat myocardial infarction and heart failure.
Factors affecting cell manufacturing time were studied in 269 patients enrolled on 3 CCTRN protocols using Sepax-separated ABMMC. The cells were prepared at 5 GMP cell processing facilities and delivered to local treatment sites or more distant satellite Centers.
Although the Sepax procedure takes only 90 minutes, the total time for processing was approximately seven hours. Contributing to this were incoming testing and device preparation, release testing, patient randomization and product delivery. The average out-of body-time (OBT), which was to be <12 hours, averaged 9 hours. A detailed analysis of practices at each Center revealed a variety of factors that contributed to this OBT.
We conclude that rapid cell enrichment procedures may give a false impression of the time actually required to prepare a cellular therapy product for release and administration. Institutional procedures also differ and can contribute to delays; however, in aggregate it is possible to achieve an overall manufacturing and testing time that is similar at multiple facilities.
Cellular therapy; Regenerative medicine; Cardiovascular cell therapy; Turnaround time
The overall risk of hemolytic transfusion reactions from plasma (minor) incompatible platelet transfusions and the role of a critical anti-A or anti-B titer in predicting/preventing these reactions has not been clearly established.
We evaluated all apheresis platelet (AP) transfusions for three months. Using the gel titer method, we determined the anti-A and/or the anti-B IgG titer for all incompatible APs. Reported febrile transfusion reactions and hemolytic transfusion reactions (HTRs) were recorded; transfusions were not prospectively evaluated by the study team. A post-transfusion DAT and eluate were performed after a reported febrile or hemolytic reaction for patients who received plasma incompatible APs.
647of 4,288 AP transfusions (15.1%) were plasma incompatible. Group O APs (N = 278) had significantly higher anti-A and anti-B titers than group A or B APs (p<0.0001). No group A or B APs had a titer >128 (0/342). For group O APs, 73 had titers ≥256 (26.3%), and 27 had titers ≥512 (9.7%). No HTRs were reported to any plasma incompatible AP transfusion during the study period. Two plasma incompatible AP transfusions were associated with fever/chills and positive DATs, of which one had a positive eluate. The incidence of a DAT and eluate positive febrile transfusion reaction in the plasma incompatible AP population is 0.15% (95% CI 0.0–0.86%).
A critical anti-A or B titer is not sufficient to predict the risk of hemolysis in patients receiving plasma incompatible APs, although underreporting of reactions to the blood bank may limit the generalizability of this study.
platelet; apheresis; ABO; antibody titer; transfusion; incompatible; febrile transfusion reaction; hemolysis
Recent studies suggest that HPA-1a–specific, low-avidity maternal antibodies not detectable by conventional methods can cause neonatal alloimmune thrombocytopenia (NAIT). We performed studies to further define the incidence and clinical significance of this type of antibody.
STUDY DESIGN AND METHODS
Surface plasmon resonance analysis was used to detect low-avidity antibodies in HPA-1a–negative, “antibody-negative” mothers of suspected NAIT cases. The ability of antibodies detected to promote immune destruction of human platelets (PLTs) was examined in a newly developed NOD/SCID mouse model.
Among 3478 suspected cases of NAIT, 677 HPA-1a–negative mothers were identified. HPA-1a–specific antibodies were detected by conventional antibody testing in 616 cases (91%). Low-avidity HPA-1a–specific antibodies were identified in 18 of the remaining 61 cases (9%). Clinical follow-up on 13 cases showed that eight were referred because of suspected NAIT and five because the mother’s sister had previously had an infant with NAIT. Only six infants born to the 13 sensitized mothers had clinically significant thrombocytopenia at birth. Three of four low-avidity antibodies tested in the mouse caused accelerated clearance of HPA-1a/a but not HPA-1b/b PLTs. Only 3 of 12 mothers with low-avidity HPA-1a antibodies were positive for HLA-DRB3*0101.
The findings confirm previous reports that low-avidity HPA-1a antibodies can cause NAIT but show that the presence of such an antibody does not predict that an infant will be affected. The low incidence of HLA-DRB3*0101 in this cohort (p < 0.0001) suggests that women negative for DRB3*0101 may be predisposed to produce low-avidity HPA-1a antibodies.
A solid phase recombinant-immunoblot-assay(RIBA) is often used to determine the specificity of antibody to hepatitis-C-virus(anti-HCV). The RIBA result is recorded as positive, negative or indeterminate. The interpretation of RIBA indeterminate reactivity and its significance to patients and blood donors are unclear. We attempted to address the clinical relevance of RIBA-indeterminate reactions in the context of the natural history of HCV infection in a prospectively followed cohort of anti-HCV positive blood donors.
STUDY-DESIGN AND METHODS
Donor demographics, HCV exposure history, humoral and cell-mediated immunity(CMI) to HCV were compared in 15 RIBA-indeterminates, 9 chronic-HCV-carriers and 8 spontaneously-recovered subjects. Serum samples were tested for the presence of anti-HCV by a liquid phase Luciferase-Immunoprecipitation-System(LIPS) assay. CMI was assessed by IFN-γ-ELISpot assay.
In the quantitative LIPS assay, the sum of antibody responses to 6 HCV-antigens showed significant (p<0.001) step-wise diminution progressing downward from chronic-carriers to spontaneously-recovered to RIBA-indeterminates. CMI responses in RIBA-indeterminates were similar to spontaneously-recovered subjects, and greater than chronic-carriers and negative controls (p<0.008). A parenteral risk factor was identified in 13% of RIBA-indeterminates as compared with 89% of chronic-carriers and 87% of spontaneously-recovered subjects. On average, donors in the RIBA-indeterminate group were older than the other groups.
The combined CMI and LIPS results suggest that persistent RIBA-indeterminate reactions generally represent waning anti-HCV responses in persons who have recovered from a remote HCV infection. In such cases, detectable antibody may ultimately disappear leaving no residual serologic evidence of prior HCV infection, as previously reported in a minority of long-term HCV-recovered subjects.
HCV; RIBA indeterminate; HCV infection spontaneously recovered; Chronic HCV infection; RIBA 3.0; Cell-mediated immunity; IFNγ; Luciferase immunoprecipitation system (LIPS) assay
The FDA requires that red cells must be refrigerated within 8 hours of whole blood collection. Longer storage of whole blood at 22°C before component preparation would have many advantages.
Study Design And Methods
Two methods of holding whole blood for 20 to 24 hours at room temperature were evaluated; i.e., refrigerated plates or a 23°C incubator. After extended whole blood storage, platelet concentrates were prepared from platelet-rich-plasma on day 1 post-donation, and the platelets were stored for 6 more days. On day 7 of platelet storage, blood was drawn from each subject to prepare fresh platelets. The stored and fresh platelets were radiolabeled and transfused into their donor.
Eleven subjects’ whole blood was stored using refrigerated Compocool plates and 10 using an incubator. Post-storage platelet recoveries averaged 47 ± 13% versus 53 ± 11% and survivals averaged 4.6 ± 1.7 days versus 4.7 ± 0.9 days for Compocool versus incubator storage, respectively (p=N.S.). Using all results, post-storage platelet recoveries averaged 75 ± 10% of fresh and survivals 57 ± 13% of fresh; platelet recoveries met FDA guidelines for post-storage platelet viability but not survivals.
Seven-day post-storage platelet viability is comparable when whole blood is stored for 22 ± 2 hour at 22°C using either refrigerated plates or an incubator to maintain temperature prior to preparing platelet concentrates.
Platelets; Platelet Concentrates; Platelet Storage
A decrease in the prevalence of hepatitis C virus antibody (anti-HCV) has been reported among voluntary blood donors in some regions of China. However, the prevalence of HCV among volunteer blood donors in other regions of China has not been reported. The aim of this study was to investigate the seroprevalence of HCV among 559,890 first-time volunteer blood donors recruited during 2004 through 2007 at the Guangzhou Blood Center, China.
Study Design and Methods
Anti-HCV was detected using two different third-generation enzyme immunoassay kits. HCV RNA was detected using reverse transcription–polymerase chain reaction (RT-PCR) targeting the 5′-untranslated region of HCV.
Among 559,890 donors, 1877 (0.335%) were positive for anti-HCV. The anti-HCV+ rate was significantly higher in males than females (0.37% vs. 0.28%; p < 0.001) and significantly lower among donors living in Guangdong Province than donors who had migrated from other locations (0.30% vs. 0.40%; p < 0.001). Among the 1877 anti-HCV+ donors, 450 were randomly selected for HCV nucleic acid amplification by RT-PCR. Of these, 270 (60%) were HCV RNA+ and 180 (40%) were HCV RNA–.
Many donors from outside Guangdong Province were migrant laborers from other areas in China, suggesting that there is regional heterogenicity in HCV prevalence within China. The overall anti-HCV+ rate reported here is among the lowest reported among blood donors in China reflecting the effect of the current recruitment of exclusively volunteer donors.
Although quantitative evidence is lacking, it is generally believed that the majority of cases of transfusion-related acute lung injury (TRALI) are caused by female blood donors. We aimed to examine the relation between female donors and the occurrence of TRALI.
STUDY DESIGN AND METHODS
We performed an international, multicenter case-referent study. TRALI patients who were diagnosed clinically, independent of serology or donor sex, and had received transfusions either only from male donors or only from female donors (unisex cases) were selected. The observed sex distribution among the donors of these TRALI patients was compared to the expected sex distribution, based on the relevant donor populations.
Eighty-three clinical TRALI cases were included; 67 cases received only red blood cells (RBCs), 13 only plasma-rich products, and three both. Among RBC recipients the relative risk (RR) of TRALI after a transfusion from a female donor was 1.2 (95% confidence interval [CI], 0.69–2.1) and among plasma-rich product recipients the RR was 19 (95% CI, 1.9–191). The p value for the difference between RBCs and plasma was 0.023.
Our data support the notion that plasma from female donors is associated with an increased risk of TRALI, while RBCs from female donors are not.
The hemoglobin of the Earthworm Lumbricus terrestris (also known as erythrocruorin, or LtEc) is a naturally occurring high molecular weight protein assembly (3.6 MDa) that is extremely stable, resistant to oxidation, and transports oxygen similarly to human whole blood. Therefore, LtEc may serve as an alternative to donated human red blood cells, however, a suitable purification process must be developed to produce highly pure LtEc on a large scale that can be evaluated in an animal model to determine the safety and efficacy of LtEc.
Materials and Methods
We used tangential flow filtration (TFF), an easily scalable and affordable technique, to produce highly pure LtEc from Earthworms. The purity, yield, methemoglobin level, viscosity, colloid osmotic pressure, O2 binding equilibria, and ligand binding kinetics of the purified LtEc was measured in vitro. The purified LtEc product was then evaluated in hamsters using a hypervolemic infusion model to establish its basic biocompatibility and detect any changes in microcirculatory and systemic parameters.
TFF was able to produce LtEc with high purity and yield (5–10 grams per 1000 worms). The purified LtEc product did not elicit hypertension or vasoconstriction when infused into hamsters.
LtEc may be easily purified and safely transfused into hamsters in small amounts (0.5–1.5 g/dL final concentration in blood) without any noticeable side-effects. Therefore, LtEc may serve as a very promising oxygen carrier for use in transfusion medicine.
hemoglobin; erythrocruorin; tangential flow filtration; oxygen carrier; red blood cell substitute; transfusion medicine
The rising costs, limited supply, and clinical risks associated with allogeneic blood transfusion have prompted investigation into autologous blood management strategies, such as post-operative red cell salvage. This study provides a cost comparison of transfusing washed post-operatively salvaged red cells using the OrthoPat device versus unwashed shed blood and banked allogeneic blood.
Study Design and Methods
Cell salvage data was retrospectively reviewed for a sample of 392 patients who underwent primary hip or knee arthroplasty. Average unit costs were calculated for washed salvaged red cells, equivalent units of unwashed shed blood, and therapeutically equivalent volumes of allogeneic packed red cells.
No initial capital investment was required for the establishment of the post-operative cell salvage program. For patients undergoing total knee arthroplasty (TKA), the average unit cost for washed post-operatively salvaged cells, unwashed shed blood, and allogeneic banked blood was $758.80, $474.95, and $765.49, respectively. In patients undergoing total hip arthroplasty (THA), the average unit cost for washed post-operatively salvaged cells, unwashed shed blood, and allogeneic banked blood was $1827.41, $1167.41, and $2609.44, respectively.
This analysis suggests that transfusing washed post-operatively salvaged cells using the OrthoPat device is more costly than using unwashed shed blood in both THA and TKA. When compared to allogeneic transfusion, washed post-operatively salvaged cells carry a comparable cost in TKA, but potentially represent a significant savings in patients undergoing THA. Sensitivity analysis suggests that in the case of TKA, however, cost comparability exists within a narrow range of units collected and infused.
blood salvage; autologous transfusion; allogeneic transfusion; cost study analysis
The mechanisms that underlie allergic transfusion reactions (ATRs) are not well characterized, but likely involve recipient, donor, and product factors. To assess product factors associated with ATRs, we investigated candidate mediators in apheresis platelet products associated with ATRs and controls.
STUDY DESIGN AND METHODS
Using bead-based and standard ELISA immunoassays, we tested supernatants from 20 consecutive apheresis platelet transfusions associated with ATRs and 30 control products for concentrations of mediators in 3 categories: acute inflammatory mediators, direct agonists of basophils and mast cells, and growth/priming factors of basophils and mast cells.
Median concentrations of the direct allergic agonists C5a, brain derived neurotrophic factor (BDNF), and CCL5 (RANTES) were 16.6%, 41.8%, and 13.9% higher, respectively, in the supernatant of apheresis platelet products that were most strongly associated with ATRs (P < 0.05 for each mediator). Other direct agonists (MIP-1α, MCP-1, eotaxin-1, IL-8) were similar between groups. Concentrations of acute inflammatory mediators and basophil growth/priming factors were also similar between groups (P > 0.2 for all associations).
The allergic agonists C5a, BDNF, and CCL5 may be mediators of ATRs in apheresis platelet products. Acute inflammatory proteins and basophil/mast cell growth and priming factors do not appear to be associated with apheresis platelet products that cause ATRs.
allergy; transfusion reaction; IgE; platelet
The biologic mechanisms of allergic transfusion reactions (ATRs) are largely unknown. We sought to compare the atopic predisposition of platelet recipients who experienced an ATR to non-reactive control recipients.
STUDY DESIGN AND METHODS
We identified 37 consecutive apheresis platelet recipients who experienced an ATR and 26 matched controls. Total IgE and aero- and food-allergen-specific IgE were quantified in plasma by ImmunoCAP (Phadia, Phadiatop and Fx5). IgE testing of apheresis platelet supernatants was also performed.
Pruritus and urticaria were manifest in 91.9% and 83.8% of all ATRs, with more severe respiratory symptoms and angioedema occurring in <15% of cases. No subject had anaphylaxis. Sex, age, and primary diagnosis were balanced between the two groups. Total and aero-allergen specific IgE was higher among subjects experiencing an ATR in comparison to control subjects (median total IgE 55.5 kU/L vs. 8.3 kU/L, P=0.002; and median aero-allergen specific IgE 0.57 kUa/L vs. 0.36 kUa/L, P=0.046). IgE antibody levels in apheresis products associated with ATRs were similar to control products (P>0.1 for all IgE tests).
Recipient atopic predisposition, as defined by IgE sensitization, is a risk factor associated with ATRs.
allergy; transfusion reaction; IgE; platelet
The characteristics of blood recipients including diagnoses associated with transfusion and post-transfusion survival are unreported in Brazil. The goals of this analysis were: 1) to describe blood utilization according to clinical diagnoses and patient characteristics at a large public hospital, Hospital das Clinicas (HC), a tertiary teaching hospital and trauma center in the city of Sao Paulo; 2) to determine the factors associated with survival of blood recipients.
A retrospective cross-sectional analysis was conducted on all inpatients in 2004. Data came from three sources were merged: HC electronic admission files, blood issue files, and the national death registry. The first two files consist of data about patient characteristics, clinical diagnosis, and transfusion information. Analyses comparing transfused and non-transfused patients were conducted. The third file was used to determine survival status of recipients up to three years after last transfusion. Logistic regression was conducted among transfused patients to examine survival curves and characteristics associated with follow up patient survival.
In 2004, 30,779 patients were admitted to HC, with 3,835 (12.4%) transfused. These patients had 10,479 transfusions episodes, consisting of 39,561 transfused components; 16,748 (42%) red cells, 15,828 (40%) platelets and 6,190 (16%) plasma. The median number of components transfused was 3 (range 1 – 656) per patient admission. Mortality during hospitalization was dramatically different for patients whose admissions included transfusion or not (24% vs. 4%). After 1 year, 56% of transfusion recipients were alive. The multivariable model of factors associated with mortality following transfusion showed that the most significant factors in descending order were hospital ward, increasing age, increasing number of components transfused, and type of components received.
Ward and transfusion are markers of underlying medical conditions and are associated with the probability of survival. Platelet transfusions are common and likely reflect the types of patients treated at HC. This comprehensive blood utilization study, first of its kind in Brazil can help in developing transfusion policy analyses in South America.
Blood donor selection is important to ensure the safety of both donors and recipients. There is a paucity of data on reasons for blood donor deferral in Ivory Coast. The aim of this study was to identify the reasons for predonation deferral at a blood collection site at General Hospital, Yopougon Attié in Abidjan.
MATERIALS AND METHODS
The investigators conducted a retrospective audit of data pertaining to donor deferral for blood donors that presented to the general hospital of Yopugon Attié from January 1, 2006 to December 31, 2008.
A total of 10,694 prospective blood donors, presented over the study period, and 24,363 attempts to donate were registered. The majority were repeat blood donors (77.4%). A total of 2618 (10.8%) donors were deferred. The most frequent reason for deferral was a low hemoglobin level (42.5%), with females constituting the majority of those deferred. The second most frequent reason for deferral was a reported change of or new sexual partner (34.3%); male donors were predominant in this group. Additional reasons for deferral included short interdonation interval (4.6%) and reactivity for a screened biomarker (2.3%).
Although the rates for permanent and temporary deferral rates are similar between the Ivory Coast and high-middle income countries, the causes and demographics differ. The reasons for exclusion are preventable through awareness and education of prospective blood donors.
Iron depletion/deficiency in blood donors frequently results in deferrals for low hemoglobin, yet blood centers remain reluctant to dispense iron replacement therapy to donors.
Study Design and Methods
During a 39-month period, 1236 blood donors deferred for hemoglobin <12.5 g/dL and 400 non-deferred control donors underwent health history screening and laboratory testing (CBC, iron studies). Iron depletion and deficiency were defined as ferritin of 9–19 mcg/L and <9 mcg/L in females and 18–29 mcg/L and <18 mcg/L in males. Deferred donors and iron-deficient control donors were given a 60-pack of ferrous sulfate 325 mg tablets, and instructed to take one tablet daily. Another 60-pack was dispensed at all subsequent visits.
In the low hemoglobin group, 30% and 23% of females and 8% and 53% of males had iron depletion or deficiency, respectively, compared with 29% and 10% of females and 18% and 21% of males in the control group. Iron depleted/deficient donors taking iron showed normalization of iron-related laboratory parameters, even as they continued to donate. Compliance with oral iron was 68%. Adverse gastrointestinal effects occurred in 21% of donors. The study identified 13 donors with serious medical conditions, including eight with GI bleeding. No donors had malignancies or hemochromatosis.
Iron depletion or deficiency was found in 53% of female and 61% of male low hemoglobin donors, and in 39% of female and male control donors. Routine administration of iron replacement therapy is safe, effective, and prevents the development of iron depletion/deficiency in blood donors.
Lipids and other biologically active substances accumulate in platelet concentrates (PCs) during storage. Some of these substances have been suggested to modulate immune responses and to play a pathogenic role in the development of transfusion-related acute lung injury. This study compared the content and impact of some biological response modifiers in PCs treated with pathogen reduction (PR) technology and nontreated PCs.
STUDY DESIGN AND METHODS
Apheresis PCs (n = 12) were split in two: one split was subjected to PR treatment (INTERCEPT, Cerus Corp.) and the other split was left untreated. Basic characterization and content of vascular endothelial growth factor (VEGF) and sCD154 were measured. Lipopolysaccharide (LPS)-induced secretion of interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α) was measured after incubation of heparinized whole blood with platelet (PLT) supernatants. The supernatants’ neutrophil (PMN)-priming capacity, and thereby activation of the NADPH oxidase, was measured as the rate of superoxide anion production after formyl-Met-Leu-Phe activation. Lipids were extracted from the supernatants on Day 6 and tested for PMN-priming activity.
Supernatants from PR-treated PCs demonstrated significantly higher mean PLT volume (MPV)3−, and significantly and O2, lower pH, CO2, and HCO less LPS-induced TNF-α secretion compared to untreated PCs. No differences in swirling, PLT count, potassium levels, glucose consumption, lactate production, IL-10, VEGF, sCD154, or PMN-priming activity were found between the groups over time.
INTERCEPT PR treatment caused no substantial differences in PCs, except for minor changes in MPV and metabolic variables. Further studies are needed to explain the differences in the LPS-induced TNF-α secretion.
In Brazil little is known about adverse reactions during donation and
the donor characteristics that may be associated with such events. Donors
are offered snacks and fluids prior to donating and are required to consume
a light meal after donation. For these reasons the frequency of reactions
may be different than those observed in other countries.
A cross-sectional study was conducted of eligible whole blood donors
at three large blood centers located in Brazil between July 2007 and
December 2009. Vasovagal reactions (VVRs) along with donor demographic and
biometric data were collected. Reactions were defined as any presyncopal or
syncopal event during the donation process. Multivariable logistic
regression was performed to identify predictors of VVRs.
Of 724,861 donor presentations, 16,129 (2.2%) VVRs were
recorded. Rates varied substantially between the three centers: 53, 290 and
381 per 10,000 donations in Recife, São Paulo and Belo Horizonte,
respectively. Although the reaction rates varied, the donor characteristics
associated with VVRs were similar [younger age (18–29),
replacement donors, first time donors, low estimated blood volume
(EBV)]. In multivariable analysis controlling for differences
between the donor populations in each city younger age, first-time donor
status and lower EBV were the factors most associated with reactions.
Factors associated with VVRs in other locations are also evident in
Brazil. The difference in VVR rates between the three centers might be due
to different procedures for identifying and reporting the reactions.
Potential interventions to reduce the risk of reactions in Brazil should be
Hemolytic reactions (HTRs) can occur from ABO-incompatible platelet transfusions. After a series of cases at our institution, a procedure to screen all plateletpheresis donors for high-titer ABO antibodies was implemented.
Study design and methods
Plasma samples from plateletpheresis donors were screened using pooled 0.8% A1 and 0.8% B RBC in buffered gel. Dilutions of 1 in 150, 1 in 200, and 1 in 250 were sequentially evaluated. A component testing positive for high-titer ABO antibodies is restricted to ABO-identical or group O recipients, or washed.
At the initial dilution of 1 in 150, half of group O components were labeled as high-titer. At the current dilution of 1 in 250, 25% of group O components are labeled as high-titer. No platelet-associated HTR has been reported since screening began.
Universal screening for high-titer ABO antibodies in plateletpheresis donors can be implemented efficiently to reduce the risk of HTRs. The cutoff for classifying a unit as high-titer depends on the serologic method used, and may be customized by the individual facility. Our screening method uses one gel test per donation regardless of blood group, and a plasma dilution of 1 in 250 with pooled A1/B RBCs in buffered gel.
Concentrating and washing apheresis platelets (APs) substantially reduce the number of allergic transfusion reactions likely due to removal of plasma. However, these processes may damage platelets. This study evaluated whether concentrating or washing APs decrease the Corrected Count Increment (CCI).
Study Design and Methods
This retrospective study evaluated individuals who initially received unmanipulated APs and subsequently received concentrated and/or washed APs at a large university hospital between 1998 and 2009. Concentrated units were prepared by reducing the plasma volume of APs by a goal of >67%. Washed units were prepared by washing the APs with 1L normal saline. The CCI (plt × m2/uL) for all transfusions was calculated. Hypothesis testing was performed with Student’s t-tests for continuous variables and chi-square tests for dichotomous variables.
We evaluated 121 individuals; 46 patients who received unmanipulated, concentrated and then washed APs, 59 patients who received unmanipulated and then concentrated APs; and 16 patients who received unmanipulated and then washed APs. Patient demographics were similar among the three groups. The mean CCI for unmanipulated AP transfusions at 0–2 hours post transfusion were significantly higher than concentrated and washed platelet transfusions (p<0.001). However, when accounting for platelet loss due to manipulation, concentrating APs did not impact the CCI, but the CCI remained significantly lower for washed products at all time points post transfusion (40.7% mean reduction at 20–24 hours, p<0.001).
Washing APs significantly reduces platelet count recovery and survival, as demonstrated by a significantly reduced CCI.
corrected count increment (CCI); allergic transfusion reaction (ATR); platelet; wash; concentrate; urticaria; hives; anaphylaxis; premedication
The DARC (Duffy blood group, chemokine receptor) gene encodes for a transmembrane glycoprotein that functions as a chemokine transporter, is a receptor for Plasmodium vivax and knowlesi, and expresses the Duffy blood group antigens (Fy). The Fy(a−b−) phenotype found in people of African descent is typically associated with a −67t>c mutation in the 5′ untranslated region (UTR), which prevents red blood cells being invaded by Plasmodium vivax and knowlesi. The aim of this study was to establish DARC allele frequencies in an African American blood donor cohort, determine a phylogenetic tree for DARC, and compare human and Neandertal DARC genes.
The DARC nucleotide sequence of 54 African American blood donors was determined from genomic DNA. Heterozygous substitutions were resolved by sequencing of haplotype specific amplifications. A phylogenetic tree for DARC was established using the neighbor-joining method with Pan troglodytes as root.
108 haplotypes of the DARC gene could be unambiguously determined from nucleotide position −300 in the 5′ UTR to +300 in the 3′ UTR. 11 different alleles were found, including the clinically relevant FY*A, FY*B, FY*B-67C, FY*B298A, and FY*X alleles. All phenotype predictions based on genotypes matched exactly the serologically determined phenotypes: 52% Fy(a−b−), 28% Fy(a−b+), and 20% Fy(a+b−).
The nucleotide sequencing approach using one amplicon is a practical genotyping method for DARC and allows the determination of haplotypes even in heterozygous constellations. We developed a phylogenetic tree for DARC alleles and postulated a distinct FY*B allele as ancestral for the extant DARC alleles in humans.
The goal of selecting a healthy blood donor is to safeguard donors and reduce the risks of infections and immunologic complications for recipients.
STUDY DESIGN AND METHODS
To evaluate the blood donor selection process, a survey was conducted in 28 blood transfusion centers located in 15 francophone African countries. Data collected included availability of blood products, risk factors for infection identified among blood donor candidates, the processing of the information collected before blood collection, the review process for the medical history of blood donor candidates, and deferral criteria for donor candidates.
During the year 2009, participating transfusion centers identified 366,924 blood donor candidates. A mean of 13% (range, 0%–36%) of the donor candidates were excluded based solely on their medical status. The main risk factors for blood-borne infections were having multiple sex partners, sexual intercourse with occasional partners, and religious scarification. Most transfusion centers collected this information verbally instead of having a written questionnaire. The topics least addressed were the possible complications relating to the donation, religious scarifications, and history of sickle cell anemia and hemorrhage. Only three centers recorded the temperature of the blood donors. The deferral criteria least reported were sickle cell anemia, piercing, scarification, and tattoo.
The medical selection process was not performed systemically and thoroughly enough, given the regional epidemiologic risks. It is essential to identify the risk factors specific to francophone African countries and modify the current medical history questionnaires to develop a more effective and relevant selection process.