Transfusion Of Cellular Blood Products Research Articles

Management of a Jehovah's Witness patient with ANCA-Associated Vasculitis Following Pfizer-BioNTech COVID-19 Vaccine

Abstract Anti-neutrophil cytoplasmic antibody (ANCA) vasculitis is defined as a systemic autoimmune disease limited to small calibre vasculature, associated with the presence of myeloperoxidase or proteinase 3. After receiving Pfizer BioNTech COVID-19 vaccine a 77-year-old woman of Jehovah's Witness faith presented with renal limited anti-MPO-AAV with underlying iron deficiency anaemia. Treatment was initiated with corticosteroids, iron repletion, Epoetin-beta, renal replacement therapy, plasma exchange with albumin, and cyclophosphamide with successful clearance of ANCA vasculitis. Although Jehovah's Witnesses may refuse transfusion of cellular blood products, they accept and expect alternative effective medical care.

Is pathogen reduction an acceptable alternative to irradiation for risk mitigation of transfusion-associated graft versus host disease?

Transfusion-associated graft versus host disease (TA-GVHD) is a highly morbid and often fatal adverse event associated with transfusion of cellular blood products [platelets, red blood cells (RBCs) and whole blood] and more rarely with never-frozen plasma products. It is caused by residual viable donor T-lymphocytes that proliferate and actively target recipient tissues. Selective or universal irradiation of blood components using gamma-irradiation and more recently, X-ray irradiation, are the most commonly applied interventions and have been validated by the demonstration of in vitro T-lymphocyte inactivation, in murine models of TA-GVHD and by years of clinical experience. Irradiation, however, has multiple limitations including a sharp dose-response curve that renders quality control of dosage critically important, the use of radioactive radiation sources that are a terrorism risk, and selective implementation in many countries that leads to inadvertent omission and patient risk exposure. Certain pathogen reduction technologies (PRT) for platelets have been approved by regulatory authorities and endorsed by professional societies as an alternative to irradiation for reducing the risk of TA-GVHD, and PRT for RBCs and whole blood are in development. While the mechanism of action of T-lymphocyte inactivation differs from gamma/X-ray irradiation, the impact on T-lymphocyte inactivation for PRT is equivalent or superior to that of irradiation as demonstrated by sensitive in vitro lymphocyte proliferation assays and in vivo mouse models that approximate human TA-GVHD. Clinical trials and cumulative routine-use experience attest to the efficacy of PRT when used as an alternative to irradiation. While T-lymphocyte inactivation efficacy varies between PRT platforms, the implementation of PRT for platelets increases blood safety for patients beyond the mitigation of TA-GVHD, by decreasing the risk of transfusion transmitted infections with known viruses, bacteria and parasites as well as emerging pathogens.

Platelet antibodies in immune thrombocytopenia and related conditions

Abstract Platelet autoantibodies are a common finding in immune thrombocytopenia (ITP) and in rare cases of antibody-mediated platelet function (“acquired thrombasthenia”). In drug-induced immune thrombocytopenia, antibodies react with platelets only in the presence of the offending drug. Alloantibodies reacting with platelets are induced by transfusion of cellular blood products or during pregnancy. They are responsible for fetal/neonatal alloimmune thrombocytopenia (FNAIT), they are able to cause febrile, nonhemolytic transfusion reactions and they give rise to insufficient platelet increments following platelet transfusions. Two rare transfusion reactions: post-transfusion purpura (PTP) and passive alloimmune thrombocytopenia (PAT) are triggered by platelet alloantibodies. This review discusses the clinical value of tests for platelet antibodies in various clinical situations related to insufficient primary hemostasis.

Transfusion Associated Graft Versus Host Disease: A Case Report and Review of Literature

Transfusion associated graft versus host disease (TA-GvHD) is a rare but usually fatal complication of transfusion of cellular blood products. It is seen usually in immunosuppressed individuals due to engraftment of viable T lymphocytes but it may also occur in immunocompetent individuals. Patients present with fever, skin rash, diarrhoea, hepatic dysfunction and bone marrow aplasia which manifests as pancytopenia. The diagnosis of TA-GvHD is often delayed because of lack of awareness due to the non-specific manifestations and often these symptoms are attributed to the underlying illness. We present here a case report of fatal TA-GvHD in an immunocompetent patient, post coronary artery bypass grafting surgery after transfusion of blood products. The patient died 27 days after a blood transfusion. An increased risk of TA-GvHD following bypass grafting and other surgical procedures where cardiopulmonary bypass is required has been perceived. TA-GvHD is under reported and the incidence is felt to be too low to warrant routine irradiation of cellular products. Physicians, surgeons and transfusion centers should be aware of this rare but devastating complication of blood transfusion so as to either diagnose it early or rather prevent it.

Babesia Screening in the U.S. Blood Supply

Transmission of Babesia microti via transfusion of cellular blood products can cause severe infection in immunocompromised or asplenic patients.

Immunomodulatory Effects of Transfusion

Immunomodulation following transfusion of cellular blood products presents as a generalized immunosuppression and/or production of alloantibody. The immunological effects of transfusion in immunocompetent subjects were evaluated in patients undergoing cardiac surgery with cardio-pulmonary by-pass.Subjects were consented for this IRB-approved study and were randomized to receive unmodified (STD) red blood cells (rbc), leukoreduced (LR) rbc or LR rbc that were g-irradiated (g-I). All platelet transfusions were collected LR and they were also g-I for the third arm. Patients were transfused only when clinically indicated. Subjects receiving no transfusions during the study served as a fourth control arm. Peripheral blood samples collected prior to surgery were controls for samples collected after surgery (day 10 +/- 4 and day 30 +/-5).HLA antibody production was evaluated in 245 subjects using single-antigen multiarray assays for antibody to both HLA class I and class II, a summary of results in shown in Table 1. For subjects with HLA antibody in their pre-surgery sample, these assays allowed evaluation of change in antibody specificity or levels. For these pre-sensitized subjects, there was no significant difference in HLA antibody production between the transfused study arms: even those not transfused showed an increase, most likely due to activation of memory responses. For subjects without HLA antibody in their pre-surgery sample, recipients of LR products showed little increase supporting prior studies showing the efficacy of LR in reducing antibody. However the protection afforded by LR was abrogated by g-I. This was an unexpected finding.We evaluated cellular and cytokine mediators of immunosuppression in the first 139 consecutive subjects of the 245 subjects enrolled in this study. This part of the study was powered for hypothesis generation, not statistical significance. Mononuclear cells (MNC) were isolated from each sample, frozen, and all samples from a subject assayed together. We assayed these cells for production of TGFB1 using ELISPOT. We used flow cytometry phenotyping for markers of CD4+25+ T regulatory cells (CTLA4, FoxP3) and for intracellular cytokines for CD4+ and CD4- NKT cells (IFNG, IL-4, IL-10). As shown in Table 2, recipients of standard rbc showed an increase (following transfusion and surgery) in TGFB1 producing mononuclear cells with a lower increase in recipients of LR rbc and those who were not transfused, but further reduced in the group receiving g-I LR products. Recipients of standard rbc or of LR rbc showed an increase of T lymphocytes expressing FoxP3 or CTLA4, and of CD4+ NKT cells producing IL-4. In contrast, subjects whose LR products were g-I showed a markedly lower increase in all three measures. These data identify an increase in mediators of immunosuppression in recipients of standard rbc and LR rbc that was reduced in recipients of g-I and LR rbc and platelets. Surgery and bypass alone increased the numbers of TGFB1+ MNC and IL4+ NKT cells suggesting a role for the innate immune system in immunosuppression following transfusion.This study is the first to exam the immunomodulatory effects of transfusion by combining measurement of immunosuppression in ex vivo surrogate assays and measurement of HLA antibody production inclusive of pre-sensitized subjects. Our observations of differences in responses to blood products prepared with g-I plus LR compared to LR alone were unexpected and require confirmation. It suggests that the reduction in immunosuppressive cells and cytokines in the recipients of g-I and LR products contributed to the increased allosensitization we observed in that arm compared to recipients of LR products. It may be possible to manipulate immunomodulation after transfusion to reach a desired goal for specific patient populations. [Display omitted] [Display omitted] DisclosuresSlichter:Department of Defense: Research Funding; Terumo BCT: Research Funding; Cerus Corporation: Research Funding; Cellphire, Inc.: Research Funding; Genentech: Research Funding.

Product Attributes and Donor Factors in Reported Cases of Transfusion-Associated Graft Versus Host Disease: A Systematic Review

▪ INTRODUCTIONTransfusion-associated graft-vs-host disease (TA-GVHD) is a rare and often fatal complication of transfusion of cellular blood products. The relative contributions of product and donor factors to the risk of TA-GVHD remain uncertain. METHODSSystematic review of all reported cases of TA-GVHD in the published literature prior to Oct 2013, without language restrictions. Cases attributed to granulocyte transfusions, passenger lymphocyte syndrome, or GVHD following stem-cell transplant (unless traced to blood components rather than the graft) were excluded. Data collected included patient demographics and health information, details of transfusion event(s) and blood component(s), clinicolaboratory features of the TA-GVHD presentation and outcome, and results of human leukocyte antigen (HLA) and chimerism studies. HLA typing was evaluated where reported for both donor (product) and recipient at either class I or class II loci. Donor/recipient pairs were categorized as D=0 when there were no identified donor HLA antigens foreign to the recipient, or D>0 when donor cells contained one or more HLA antigens not found in the recipient. This classification applied separately to HLA class I and class II loci for each case. RESULTSAfter removing duplicates, 2130 citations discovered by the search were examined by two independent reviewers, with 394 identified as publications of interest for complete review. An additional 21 publications were found from the initial review, for a total of 415 publications. Of these, 195 publications described 348 unique cases for inclusion.Component: The component implicated in TA-GVHD was identified in 248 (71%) cases: Red cells (RBC) in 132 (38%); whole blood (WB) in 92 (26%); platelets in 20 (6%); buffy- coat product in 2 (0.6%); and plasma and plasma-reduced blood in one case each. In 100 (29%) cases, the blood component was either not specified or not identified among several potentially responsible components.Storage: Component storage time was reported in 158 (45%) cases. Of these, the implicated product was either described as “fresh” or </=10 days old in 148 (94%). 10 (6%) cases reported a storage time >10 days (maximum 14 days).Related donor: In 63 cases, the donor was either related (n=61) or deliberately HLA-matched (n=2) to the recipient, while in 113 cases the donor was unrelated. The remaining cases either reported a “possible” related donor or did not report the donor-recipient relationship.Leukoreduction/Irradiation: Leukoreduction status was reported in 135 (39%) cases. Of these, the implicated product was leukoreduced in 23 (17%) (10 bedside, 2 pre-storage, 11 not specified). The product was irradiated in 9 cases.HLA: HLA typing of recipient and donor, by serological or molecular techniques, was available for 84 cases (74 cases Class I, 62 Class II). Among patients with HLA data available, 20 (24%) had an underlying diagnosis warranting irradiation by current standards, while 64 (76%) did not. The category of D=0 was found in 47 (64%) of cases with reported class I typing; 44 (71%) of cases with reported class II typing; and 60 (71%) overall (Figure 1). There were 9 cases in which the category of D=0 could be ruled out for both HLA I and II. In the remaining 15 cases, the category of D=0 at either HLA I or II could not be definitively ruled in or out based on reported data. When considering those in whom the presence or absence of D=0 could be definitely determined, while D=0 at either HLA class I or class II was present in 55 of 57 (96%) of recipients without an indication for blood component irradiation, D=0 was present in only 5 of 12 (42%) of recipients with an indication for irradiation, p< 0.0001 (Table 1). CONCLUSIONSThe most common components implicated in TA-GVHD were WB and RBC. Most units were non-leukoreduced and stored for <10 days. Most cases of TA-GVHD occurred in recipients without a standard indication for irradiation. The absence of a foreign donor antigen at either HLA class I or class II occurred in a large majority of cases and was significantly more common in TA-GVHD among recipients without an indication for irradiation compared with those in whom irradiation would be indicated, suggesting that this donor-recipient relationship is the predominant risk factor in the development of TA-GVHD. Policies for irradiating cellular blood components based solely on the diagnosis of the recipient may fail to address all relevant risk factors for TA-GVHD. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Human T-cell lymphotropic virus type 1 infection among U.S. Thalassemia patients

Abstract Thalassemia is an inherited genetic disorder requiring multiple transfusions to treat anemia caused by low hemoglobin levels. Thus, thalassemia patients are at risk for infection with blood-borne pathogens, including human T cell lymphotropic viruses (HTLV) that are transmitted by transfusion of cellular blood products. Here, we examined the prevalence of HTLV among 234 U.S. thalassemia patients using sera collected in 2008. Sera were tested for antibodies to HTLV-1/2 using enzyme immunoassay (EIA) and a confirmatory western blot (WB) that differentiates between HTLV-1 and HTLV-2. Demographic information and clinical information were collected at study enrollment, including HIV and hepatitis C virus (HCV) status. Three patients (1.3%) were WB positive; two were HTLV-1 and one could not be serotyped as HTLV-1/2. All three HTLV-positive persons were HIV-1 negative and one was HCV seropositive. The HTLV seroprevalence was higher than that of HIV-1 (0.85%) and lower than HCV (18.8%) in this populatio...

Human T Cell Lymphotropic Virus Type 1 Infection Among U.S. Thalassemia Patients

Thalassemia is an inherited genetic disorder requiring multiple transfusions to treat anemia caused by low hemoglobin levels. Thus, thalassemia patients are at risk for infection with blood-borne pathogens, including human T cell lymphotropic viruses (HTLV) that are transmitted by transfusion of cellular blood products. Here, we examined the prevalence of HTLV among 234 U.S. thalassemia patients using sera collected in 2008. Sera were tested for antibodies to HTLV-1/2 using enzyme immunoassay (EIA) and a confirmatory western blot (WB) that differentiates between HTLV-1 and HTLV-2. Demographic information and clinical information were collected at study enrollment, including HIV and hepatitis C virus (HCV) status. Three patients (1.3%) were WB positive; two were HTLV-1 and one could not be serotyped as HTLV-1/2. All three HTLV-positive persons were HIV-1 negative and one was HCV seropositive. The HTLV seroprevalence was higher than that of HIV-1 (0.85%) and lower than HCV (18.8%) in this population. All three patients (ages 26-46 years) were diagnosed with β-thalassemia shortly after birth and have since been receiving multiple transfusions annually. Two of the HTLV-positive patients confirmed receiving transfusions before HTLV blood screening was implemented in 1988. We identified a substantial HTLV-1 seroprevalence in U.S. thalassemia patients that is much greater than that seen in blood donors. Our findings highlight the importance of HTLV testing of patients with thalassemia and other diseases requiring multiple transfusions, especially in recipients of unscreened transfusions. In addition, appropriate counseling and follow-up of HTLV-infected patients are warranted.

Allosensitization in Cardiac Transplantation

Allosensitization in Cardiac Transplantation

How do we prevent transfusion‐associated graft‐versus‐host disease in children?

The prevention of transfusion-associated graftversus-host disease (TA-GVHD) is critical for the reduction of transfusion-related risks. Because this complication of transfusion is difficult to treat and, consequently, has a high mortality rate, the optimal approach to management ofTA-GVHD is prevention. TA-GVHD is associated with the transfusion of cellular blood products (blood components that contain cells that retain the capability to engraft in a transfusion recipient), and prevention is most commonly achieved through gamma irradiation. Because prevention is critical, it is of the utmost importance to identify at-risk patients accurately. Although irradiation is quite effective at preventing TA-GVHD, there are suboptimal effects of irradiation on the red blood cell (RBC) membranes and increased costs that must be balanced. These factors lead to the adoption of selective protocols with only particular patients receiving irradiated blood products. We advocate less selective protocols and we highlight here our age-related policy for prevention of TA-GVHD in children with undiagnosed congenital immunodeficiency.

Recipients potentially infected with parvovirus B19 by red blood cell products

Since 2000, blood donor screening for parvovirus B19 (B19) by nucleic acid testing (NAT) at the Ulm Institute has been conducted 6 to 8 weeks postdonation, that is, after transfusion of cellular blood products, whereas at the Frankfurt Institute all donations are screened before releasing any blood product. In this study, we evaluated the infectivity of B19-positive blood products in relation to the virus concentration in the transfused blood component. Recipients were classified into two groups (A, transfused with blood products with B19 virus load less than 10(5) IU/mL; and B, transfused with blood products with B19 virus load greater than 10(5) IU/mL). Phylogenetic analyses were done for B19 DNA-positive donor and recipient pairs in the variant VP-1u genome region. All samples were investigated for immunoglobulin (Ig)M and IgG B19 antibodies. B19 DNA was detected in 9 of 18 recipients of red blood cells (RBCs) from Group B, whereas none of the 16 recipients of RBCs from Group A were positive for B19 DNA (p=0.016). Phylogenetic analysis demonstrated identical genomic sequences between the donors and recipients. Because recipient B19 DNA and antibody results were not available before transfusion, we interpret our overall data to indicate equivocal evidence of B19 transmission by RBC transfusion. B19 transmission by cellular blood products correlates with the virus concentration and the concentration of neutralizing antibodies. Thus, blood donor screening for B19 by minipool NAT should be done to supply at-risk patients (e.g., immunosuppressed patients) with B19-negative blood components.

Transfusion associated graft versus host disease in an immunocompetent individual following coronary artery bypass grafting

Transfusion associated graft versus host disease (TA-GVHD) is a rare but commonly fatal complication of transfusion of cellular blood products, which usually occurs in immunosuppressed individuals following transfusion and subsequent engraftment of viable T lymphocytes. Very rarely it may arise in apparently immunocompetent individuals. The clinical syndrome consists of fever, skin rash, diarrhoea, hepatic dysfunction, and bone marrow aplasia. The outcome is nearly always fatal. We present here a case report of fatal TA-GVHD in a “presumed” immunocompetent patient, post coronary artery bypass grafting surgery after transfusion of blood products. The patient died 24 days after transfusion.There is a perceived increased risk of TA-GVHD following bypass grafting and other surgical procedures where cardiopulmonary bypass is required. TA-GVHD is probably underreported and the incidence is felt to be too low to warrant routine irradiation of cellular products for this group of patients. Clinicians, pathologists, and transfusion centers should be aware of this rare but devastating complication of blood transfusion after cardiac surgery.

Potential and limitation of UVC irradiation for the inactivation of pathogens in platelet concentrates

Pathogen contamination, causing transfusion-transmitted diseases, is an ongoing concern in transfusion of cellular blood products. In this explorative study, the pathogen-inactivating capacity of UVC irradiation in platelet (PLT) concentrates was investigated. The dose dependencies of inactivation of several viruses and bacteria were compared with the effect on PLT quality. The potential of UVC irradiation was studied with a range of lipid-enveloped (LE) and non-lipid-enveloped viruses (NLE) and bacteria. LE viruses were bovine viral diarrhea virus (BVDV), human immunodeficiency virus (HIV), pseudorabies virus (PRV), transmissible gastroenteritis virus (TGEV), and vesicular stomatitis virus (VSV). NLE viruses were canine parvovirus (CPV) and simian virus 40 (SV40). Bacteria were Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Bacillus cereus. After spiking and irradiation, samples were tested for residual infectivity and reduction factors (RFs) were calculated. Furthermore, the effect of UVC irradiation on PLT quality was determined by measuring in vitro quality variables. A UVC dose of 500 J per m(2) resulted in acceptable PLT quality (as measured by pH, lactate production, CD62P expression, and exposure of phosphatidylserine) and high RFs (>4 log) for CPV, TGEV, VSV, S. epidermidis, S. aureus, and E. coli. Intermediate RFs (approx. 3 log) were observed for BVDV, PRV, and B. cereus. Low RFs (approx. 1 log) were found for HIV and SV40. No differences in virus reduction were observed between cell-free and cell-associated virus. UVC irradiation is a promising pathogen-reducing technique in PLT concentrates, inactivating bacteria, and a broad range of viruses (with the exception of HIV) under conditions that have limited effects on PLT quality. Further optimization of the UVC procedure, however, is necessary to deal with blood-borne viruses like HIV.

Prevalence and risks of allosensitization in HeartMate left ventricular assist device recipients: The impact of leukofiltered cellular blood product transfusions

Allosensitization of left ventricular assist device recipients has been associated with perioperative transfusion of cellular blood products. The relative sensitizing contribution of leukofiltered cellular blood products, however, remains unclear. We investigated the pattern of sensitization in left ventricular assist device recipients in relation to cellular blood product transfusions received. Seventy-one consecutive nonsensitized recipients of the HeartMate left ventricular assist device (Thoratec Corporation, Pleasanton, Calif) as a bridge to transplantation were reviewed. Panel-reactive HLA antibody levels at consecutive times after device implantation were correlated with perioperative cellular blood product transfusions. Fifty-four patients received leukofiltered cellular blood products (transfused), whereas 17 patients received only fresh-frozen plasma (nontransfused). Among nontransfused patients, 58.8% (10/17) became sensitized during mechanical support, versus 35.2% of transfused patients (19/54, P = .15). There was a trend toward more sensitization during the 12 weeks after device placement in nontransfused patients. Kaplan-Meier analysis revealed significantly more sensitization in nontransfused patients than in transfused patients, despite equal rates of transplantation (P = .05). A dose-response analysis revealed significant trends toward less sensitization and lower peak panel-reactive antibody level with more cellular blood product transfusions (P = .04). Multivariate Cox regression revealed only increasing transfusions to be associated with a reduced risk of sensitization (hazard ratio 0.18, P = .01). Sensitization becomes more prevalent with increasing length of support. Avoidance of perioperative leukocyte-filtered cellular blood product transfusions does not decrease the incidence or degree of HLA sensitization. Conversely, cellular blood product transfusions may be associated with lessened alloimmunization and may mitigate the sensitization seen in recipients of the HeartMate left ventricular assist device as a bridge to transplantation.

Comparison of Fungal and Nonfungal Infections in a Broad-Based Surgical Patient Population

Our aim was to compare fungal and nonfungal infections among a diverse surgical patient population. Data on all hospital-acquired infectious episodes among surgical intensive care unit and ward patients were collected prospectively over six years at a single university hospital. The relationships between fungal and nonfungal infection and over 100 variables were examined using univariate and multiple logistic regression analysis. During the study period, 3,980 infectious episodes were identified; 554 were associated with fungal infection. Multiple logistic regression analysis demonstrated that markers of severity of acute illness (higher APACHE II scores and white blood cell counts, greater transfusion of cellular blood products, mechanical ventilator dependency, and prior infection) predicted fungal infection, whereas markers of chronic illness (comorbidities) did not independently predict either fungal or nonfungal infection. Patients with fungal infection were treated with more antibiotics for longer periods of time, had prolonged lengths of stay, and more often died compared with nonfungal infection patients. A separate multiple logistic regression analysis demonstrated that both fungal infection and the number of fungal sites of infection independently predicted mortality. Of all fungal isolates, only Candida albicans and Aspergillus spp. independently predicted mortality. Fungal infections differ significantly in character and outcomes from nonfungal infections among surgical patients.

Saudi National Guard donor screening for human T cell lymphotropic virus I/II: time to use molecular biology techniques.

Human T cell lymphotropic virus (HTLV) I/II is a retrovirus that is usually transmitted through transfusion of cellular blood products, sexual contact, and vertically from mother to child through breastfeeding. Policies to screen donated blood for this virus have varied from country to country, based on seroepidemiological data. Before 1991, no such data existed on HTLV-I/II among the Saudi population. Since then, several reports have documented a low seroprevalence rate among Saudi blood donors (0-0.026%). We did a retrospective review of all blood donated at King Fahad National Guard Hospital over the preceding 3 years to assess the seroprevalence of HTLV-I/II. After retesting positive and borderline samples, we were able to detect 1 positive and 38 borderline samples. As well, we reviewed the Saudi literature to identify the national seroprevalence of the disease and propose a cost-effective approach for screening donated blood in Saudi Arabia for HTLV-I/II.

Avoidance of cellular blood product transfusions in LVAD recipients does not prevent HLA allosensitization

Background Transfusion of cellular blood products during left ventricular assist device (LVAD) implantation has been associated with HLA allosensitization, resulting in the need for a negative prospective cross-match and prolonged transplant waiting times. In order to prevent this risk, we developed a protocol to avoid transfusion of cellular blood products. Methods The protocol included preoperative patient stabilization, perioperative recombinant erythropoietin and blood conservation strategies, and postoperative monitoring of mixed venous oxygen saturation (SVO 2) to assure adequate peripheral oxygen delivery. Panel reactive antibody (PRA) was measured in all patients pre and post LVAD placement to assess HLA sensitization. Results Seven consecutive patients underwent LVAD implantation without transfusion of blood or platelets, one of whom expired perioperatively. Mean hematocrit was 35.2% preoperatively, and 21.8% postoperatively, reaching a nadir of 20.2%. Postoperative SVO 2 was >60% in all patients. In the six survivors, mean hematocrit reach 24.3%, 27.3%, and 33.0% by postoperative day seven, fourteen, and thirty, respectively. PRA in three patients was 0% preoperatively and remained 0% until transplantation after 33, 34, and 50 days of support. In two patients, preoperative PRA was 7% and 17%, dropped to 3% and 0% after thirty days, then progressively rose to 96% and 100% after 60 and 90 days, respectively. In one other patient, preoperative PRA was 0%, remained at 0% after thirty days, then rose to 96% by 60 days. Conclusions Avoiding transfusion of cellular blood products in LVAD recipients is safe and well tolerated, but does not universally protect from HLA allosensitization. Other factors may also produce sensitization, such as immunogenic components of the LVAD, soluble antigen in fresh frozen plasma, or latent sensitization which is not initially evident in critically ill and possibly anergic patients.