Efficacy of Epstein-Barr virus removal by leukoreduction of red blood cells

The influence of leukoreduction on the acute transfusion-related complication rate in 455 dogs receiving 730 packed RBCs: 2014-2017

OBJECTIVE

To investigate the influence of prestorage leukoreduction of packed RBCs (pRBCs) on acute transfusion-related complication rate in dogs.

SETTING

Two private referral hospitals.

DESIGN

Retrospective case study.

ANIMALS

Four hundred and fifty-five dogs receiving nonleukoreduced (nLR) or leukoreduced (LR) pRBC between January 1, 2014 and July 31, 2017.

MEASUREMENTS AND MAIN RESULTS

Transfusions were retrospectively reviewed to record data about the patient, donor, unit, transfusion event, acute complications, hospital discharge, and cause of death. Of 730 transfusion events in 455 dogs, 288 used LR pRBC and 442 used nLR pRBC. There was a 18.9% (138/730) overall complication rate. Seven (0.96%) complications were life-threatening. The most common complications were pyrexia (5.6%), gastrointestinal signs (4.9%), and hemolysis with no other signs (4.1%). Pyrexia with no other clinical signs, consistent with a febrile nonhemolytic transfusion reaction (FNHTR), occurred in 3.2% of transfusion events. There was a significant (P = 0.03) decrease in the rate of FNHTR with LR pRBC (1%) versus nLR pRBC (4.5%). Use of LR pRBC did not decrease in-hospital mortality. The odds of any complication, hemolysis only, FNHTR, and more severe complications increased with pRBC age. Leukoreduction did not decrease the impact of pRBC age on these complications. Use of older pRBC did not increase the incidence of life-threatening complications or mortality. Dogs receiving pRBC for blood loss were more likely to have gastrointestinal and more severe complications than those dogs that had hemolysis. The effect of pRBC unit age on complications was not influenced by the underlying reason for transfusion. Dogs that received a previous transfusion were more likely to have respiratory complications.

CONCLUSION

In this study, the use of LR pRBC was associated with a decreased rate of FNHTR but no other complications. Unit age was associated with the incidence of hemolysis, FNHTR, and complication severity but not the rate of life-threatening complications or mortality.

Transfusion-related Epstein-Barr virus (EBV) infection: A multicenter prospective cohort study among pediatric recipients of hematopoietic stem cell transplants (TREASuRE study)

BACKGROUND

Epstein-Barr virus (EBV) is carried in the blood of most adults, and transfusion-related infections have been reported. EBV is particularly deleterious in immunosuppressed transplant patients. The aim was to determine if EBV transmission occurred through leukodepleted blood product transfusion in pediatric recipients of hematopoietic stem cell transplants (HSCT).

STUDY DESIGN AND METHODS

This prospective Canadian multi-center cohort study includes 156 allogeneic HSCT pediatric recipients. The association between EBV and transfusion was analyzed using Cox regressions. EBV infection, defined by a PCR+ test in the blood of seronegative recipients of an EBV-negative graft, was monitored in order to correlate the recipient EBV strain with that of the blood donors. EBV genotypes were determined by PCR amplification followed by DNA sequencing at two loci (EBNA3b and LMP1).

RESULTS

No statistically significant associations were found between transfusions and EBV. One case of post-transplant EBV infection was identified among the 21 EBV-seronegative recipients receiving an EBV-negative graft. A total of 22 blood donors were retraced to determine whether the recipient's EBV strain matched that of a donor. One donor strain showed 100% sequence homology at the EBNA3b locus, but differed by one or two point mutations and by a 132-bp deletion at the LMP1 locus. The blood donor in question was alone among the 22 donors to show amplifiable virus in plasma. Blood from this donor readily produced an immortalized lymphoblastoid cell line in culture.

CONCLUSION

While considered a rare event, EBV transmission through transfusion may occur in the context of severe immunosuppression.

Vaccine immune response, autoimmunity and morbidity after neonatal blood exchange transfusion

INTRODUCTION

A blood exchange transfusion (BET) is most commonly performed to treat severe neonatal haemolytic disease. A distinct form of blood transfusion adverse reaction is transfusion-related immunomodulation. The purpose of our retrospective single-centre case-control cohort study was to investigate whether a blood exchange transfusion in the neonatal period provokes immunomodulation and affects humoral immune response to vaccination, morbidity and occurrence of autoantibodies.

METHODS

Study subjects were 74 apparently healthy children, who were born at term as appropriate for gestational age and received four doses of diphtheria and tetanus toxoid vaccine. Forty-one received BET due to neonatal hemolytic disease and no other blood product afterwards, while 33 did not receive any blood products. Analysis of diphtheria, tetanus and autoimmune antibodies was performed and their medical records were analyzed for infectious, allergic, cancerous and autoimmune diseases.

RESULTS

A clearly exaggerated immune response to diphtheria (1.016 IU/mL, 95% confidence interval (CI) 0.662-1.369 IU/mL vs. 0.515 IU/mL, 95% CI 0.363 to 0.626 IU/mL, P = 0.011) and slightly exaggerated immune response to tetanus vaccine (1.798 IU/mL, 95% CI 1.180-2.416 IU/mL vs. 1.036 IU/mL, 95% CI 0.398-1.673 IU/mL, P = non-specific) were observed in BET subjects. A propensity towards autoimmunity (25.8% vs. 12.5%, P = non-specific) was observed in BET subjects. However, BET in the neonatal period did not influence the occurrence of bacterial, childhood viral diseases with exception of varicella (43.9% vs. 21.2%, P = 0.040), autoimmune and cancer diseases.

CONCLUSION

BET impacted humoral immune response to diphtheria and tetanus vaccine and occurrence of autoimmune antibodies, but did not affect morbidity and the occurrence of autoimmune diseases. These effects could be related to massive antigenic load of BET and an accelerated priming of immune cells and consequent immunomodulation.

Role of Leukoreduction of Packed Red Blood Cell Units in Trauma Patients: A Review

Hemorrhagic shock is a leading cause of mortality within the trauma population, and blood transfusion is the standard of care. Leukoreduction filters remove donor leukocytes prior to transfusion of blood products. While the benefits of leukocyte depletion are well documented in scientific literature, these benefits do not translate directly to the clinical setting. This review summarizes current research regarding leukoreduction in the clinical arena, as well as studies performed exclusively in the trauma population.

Leucoreduction of blood components: an effective way to increase blood safety?

Over the past 30 years, it has been demonstrated that removal of white blood cells from blood components is effective in preventing some adverse reactions such as febrile non-haemolytic transfusion reactions, immunisation against human leucocyte antigens and human platelet antigens, and transmission of cytomegalovirus. In this review we discuss indications for leucoreduction and classify them into three categories: evidence-based indications for which the clinical efficacy is proven, indications based on the analysis of observational clinical studies with very consistent results and indications for which the clinical efficacy is partial or unproven.

Detection of Epstein-Barr virus in leucoreduced blood products

This study examined the prevalence of three human herpesviruses (HHV), namely HHV-4 (Epstein-Barr virus/EBV), HHV-6b and HHV-7 in leucoreduced blood products obtained from the Sainte-Justine Hospital blood bank. A total of 100 specimens, including 34 red blood cell concentrates, 33 platelet bags and 33 plasma units, were collected and screened by a sensitive PCR assay using virus-specific primers. Positive units were then retested by quantitative PCR. Of the 100 specimens, one platelet unit tested positive for EBV.

No evidence of transfusion transmission of Adenovirus and Epstein-Barr virus infections in paediatric recipients post-bone marrow transplant

Adenovirus and Epstein-Barr virus can cause significant morbidity and mortality in paediatric patients post-bone marrow transplant. The source of infection is thought to be either reactivation of latent viruses or primary infection. We have investigated whether transfusion of blood components from viraemic donors could provide a route of primary infection in these patients and sought the prevalence of viraemia in the blood donor population from England. In 32 linked donor/recipient samples and 300 unselected blood donors, we found no evidence to suggest that these infections in paediatric bone marrow transplant recipients had been acquired from transfused blood components.

Effects of storage and leukoreduction on lymphocytes and Epstein-Barr virus genomes in platelet concentrates

BACKGROUND

Epstein-Barr virus (EBV) persists in infected B lymphocytes in blood donors. Lymphocytes are viable during platelet (PLT) storage. The effects of storage and leukoreduction on lymphocytes and EBV genomes are evaluated.

STUDY DESIGN AND METHODS

Forty nonleukoreduced PLT concentrates were stored at 20 to 24°C for up to 7 days. EBV genomes in B cells were quantified on Days 1 and 5. Viable white blood cells (WBCs) and T and B cells were quantified in 10 of 40 units on Days 1, 3, 5, and 7 of storage. For the leukoreduction study, four pools of PLTs were leukoreduced within 24 hours of collection. B cells from before leukoreduction and all peripheral blood mononuclear cells from after leukoreduction were assayed for EBV.

RESULTS

Viable WBCs and T cells were stable whereas viable B cells were reduced to 71% of the Day 1 level by Day 5. A total of 31 of 37 (83.8%) units were EBV positive. Although EBV genomes remained stable in most units, 12 of 37 units demonstrated a median of 5.1 (range 2- to 134)-fold increase in EBV genomes per 105 B cells on Day 5. For the leukoreduction study, EBV genomes were detected in four of four pools before leukoreduction with a median of 3.8 (range, 0.2-93.6) EBV genomes per 105 B cells. EBV genomes were not detected in any of the postleukoreduction specimens.

CONCLUSIONS

Seventy percent of B lymphocytes are viable on Day 5 of PLT storage. Although the mean number of EBV genomes remained stable, a subset of units had increased EBV genomes during storage. Leukoreduction removed polymerase chain reaction-detectable EBV genomes from PLT pools.

Detection of HHV-8 (human herpesvirus-8) genomes in induced peripheral blood mononuclear cells (PBMCs) from US blood donors

BACKGROUND

Human herpesvirus-8 (HHV-8) causes Kaposi's sarcoma and can be detected and induced in peripheral blood mononuclear cells (PBMCs) from infected individuals. The prevalence of viral genomes in induced/cultured PBMCs from healthy blood donors has not been systematically studied.

MATERIALS AND METHODS

PBMCs from 164 donors were purified and stored as two equal aliquots in liquid nitrogen. One aliquot was used for CD19+ B-cell purification with a fraction reserved for DNA extraction. The second aliquot was cultured for 2 or 4 days in culture media containing n-butyrate and tetradecanoyl phorbol acetate. DNA was extracted from all four cell sources: PBMCs, purified B cells, induced PBMCs harvested at days 2 and 4 of culture. A sensitive real-time PCR with a DNA equivalent of 3×10(5) cells per reaction was run in duplicate for all samples along with a quantitative HHV-8 DNA standard ranging from 1.6 to 200 copies.

RESULTS

For all 164 donors, HHV-8 genomes were not detected in the DNA equivalent of 3-6×10(5) of PBMCs and induced/cultured PBMCs with a real-time PCR assay (95% CI: 0-3.5/164). HHV-8 DNA was not detected from DNA equivalent of 1.5 (0.5-5.6)×10(5) CD19+ B cells from 139/164 donors. HHV-8 antibodies were detected in 7 of the 164 donors (4.3%).

CONCLUSIONS

HHV-8 genomes were not detected from PBMCs, induced/cultured PBMCs and CD19+ B cells from 164 blood donors. The level of detectable HHV-8 genomes in blood donors seems to be extremely low, if they exist.

Human herpesvirus 8 genomes and seroprevalence in United States blood donors

BACKGROUND

Human herpesvirus 8 (HHV-8) is a gamma-herpesvirus that causes Kaposi's sarcoma. The prevalence of HHV-8 genomes in US blood donors has not been systemically studied.

STUDY DESIGN AND METHODS

A sensitive and quantitative real-time polymerase chain reaction (PCR) assay was used to detect HHV-8 DNA from purified CD19+ B lymphocytes from randomly selected US whole blood donors. Cellular target for the GAPDH gene was used to quantify cell-equivalent DNA. HHV-8 PCR was run in duplicate for each donor specimen along with an HHV-8 genomic copy standard. HHV-8 antibodies were detected by an indirect immunofluorescence assay.

RESULTS

Specimens were obtained from 962 blood donors. DNA from more than 3 x 10(5) B-cell equivalents were obtained from 684 donors. No HHV-8 DNA was detected from any of the blood donor specimens. For the 684 donors, HHV-8 genomes were not detected in the DNA equivalent of 3 x 10(5) to 6 x 10(5) CD19+ B cells with real-time PCR, which has a detection limit of eight copies (95% confidence interval, 0-3/684). Negative results from the remaining 220 donors were potentially confounded by insufficient input DNA into the PCR procedures. Antibodies to HHV-8 were detected in 7.3% (70/962) of the donors. HHV-8 genomes were not detected from 40 of 70 HHV-8-seropositive donor B-cell DNA samples.

CONCLUSION

The results indicate that the prevalence of detectable HHV-8 genomes in healthy blood donors is very low.

[Evolution of techniques for preparation of labile blood products (LBP): pathogen inactivation in LBP]

The techniques for inactivation of pathogens in labile blood products (LBP) would appear to be the new strategy which will permit us to increase transfusion safety in the face of the risks of transmission of pathogenic agents by LBP. Various methods are in the course of development or already validated and used in France. The latter only apply however to plasma or platelet concentrates. The mechanisms of action and the efficacy of inactivation and attenuation of pathogenic agents vary with the different techniques. Each of these constitutes a preparative procedure composed of unit steps which have to be fully mastered in order to ensure the quality and transfusion efficacy of the treated product.

Herpesvirus prevalence and viral load in healthy blood donors by quantitative real-time polymerase chain reaction

BACKGROUND

After primary infection, human herpesviruses (HHVs) maintain long-term latent persistence, often punctuated years later by sporadic episodes of symptomatic lytic activation. Also, blood-borne herpesvirus from healthy persistently infected blood donors can lead to active primary infection of immunocompromised transfusion recipients.

STUDY DESIGN AND METHODS

Utilizing a set of newly developed real-time polymerase chain reaction assays for detection and quantification of all eight human herpesviruses, the prevalence and viral DNA load of white cell-enriched blood from 100 randomly selected blood donors from the southeast Texas region are reported.

RESULTS

Herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus (VZV), and HHV-8 DNA were not detected in any donor sample. In contrast, Epstein-Barr virus (EBV) (72%) and HHV-7 (65%) were commonly detected, HHV-6 (30%) was often detected (Type B only), and cytomegalovirus (CMV; 1%) was rarely detected. Median viral loads of positive samples (per milliliter of blood) ranged from 4278 for HHV-6 to less than 46 for EBV.

CONCLUSIONS

These results suggest that the potential for transfusion-mediated transmission of herpesviruses from healthy adult blood donors is high for EBV and HHV-7; moderately high for HHV-6; uncommon for CMV; and rare for HSV-1, HSV-2, VZV, and HHV-8. Perhaps the most remarkable finding in this study was the detection of a single donor sample with greater than 6.1 x 10(7) HHV-6 Type B genome equivalents per mL blood. Given that this extraordinarily high level of HHV-6 DNA was obtained from a healthy adult blood donor, this phenomenon is likely unrelated to active infection or immunodeficiency.

Second malignancies after allogeneic hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (allo-HCT) may prolong life and cure patients suffering from otherwise fatal diseases. However, the growing population of long-term survivors has led to the realization of multiple long-term complications, including the risk of second malignancies. Compared to the autologous setting, allo-HCT carries a much higher risk of posttransplant lymphoproliferative disorder (PTLD), which usually occurs within the first year after allo-HCT and is strongly associated with the Epstein-Barr virus (EBV). Treatment-related myelodysplastic syndromes (tMDS) and second leukemias are extremely rare. Both autologous and allo-HCT carry increased risks for second solid malignancies (SSM). The cumulative incidence of SSM continues to increase in each of the largest studies with as much as 20 years of follow-up, likely related to the long latency of radiation-related SSM. Systematic, prospective monitoring, vigilant screening processes, and well-maintained survivorship clinics and databases are absolute necessities, and should be included in the infrastructure of individual transplant centers and networks, with mandatory periodic reporting of second malignancy incidences. Primary care and transplant physicians alike must be aware of the risk of second malignancies after allo-HCT. Most importantly, guidelines should be developed in regard to screening and prevention of second malignancies, so that physicians can provide state-of-the-art counsel and care for the benefit of our patients.

Leukocyte Reduction's Role in the Attenuation of Infection Risks among Transfusion Recipients

Despite advances in the screening of donated blood for infectious agents, the risk of transmitting viral, bacterial, and protozoal infections, as well as newly emerging diseases, via transfusion persists. A complementary approach is leukocyte reduction (LR), the removal of leukocytes from donated blood by filtration. Published evidence, establishing the benefit of LR in reducing the risk of febrile nonhemolytic reactions, cytomegalovirus transmission, and human leukocyte antigen alloimmunization has led to its use for some time for the care of immunosuppressed and other individuals considered to be at high risk for such complications. Recent literature suggests that LR may be effective in reducing the risk of transmission of a number of additional transfusion-transmitted infectious agents, including herpesviruses, retroviruses, bacteria, protozoa, and prions. There is also evidence that LR may reduce the risk of transfusion-related immunomodulation, further contributing to protection against infections that would complicate treatment. With the mounting evidence of potential benefit, a number of countries, as well as many hospitals and blood centers in the United States, have adopted a policy of performing LR for all donated blood. Physicians who care for immunosuppressed patients and those who are responsible for institutional infection-control practices should remain informed of the growing body of literature on LR.

Stability of lymphocytes and Epstein?Barr virus during red blood cell storage

BACKGROUND

The Epstein-Barr virus (EBV) establishes and maintains latent infection in B lymphocytes of the healthy adults. Lymphocytes remain viable during red blood cell (RBC) storage. The effect of RBC storage on the stability of EBV-infected B lymphocytes and EBV genome is not known.

STUDY DESIGN AND METHODS

Eight randomly selected non-leukoreduced AS-5 RBC units were stored for 42 days under standard blood bank refrigerated at 1-6 degrees C. Cell count and EBV genomes in CD19+ B lymphocytes were measured in fresh products and weekly for 6 weeks. Total white blood cells (CD45+), T lymphocyte (CD3+), and B lymphocyte (CD19+) were quantified by a single platform flow cytometric assay. EBV genomes were quantified by real-time polymerase chain reaction using DNA purified from CD19+ B cells.

RESULTS

Viable white blood cell, T and B lymphocytes followed a biphasic decline curve during RBC storage consisting of a steep steady decline during the first 3 weeks followed by a plateau for the remainder of the storage. At the end of the RBC shelf-life, 19% of the original T and B cells remained viable. EBV genomes per 10(5) CD19+ B lymphocytes remained constant during RBC storage. However, the total EBV genomes in the RBC units decline by more than 80% of their original value at the end of RBC storage due to loss of viable B lymphocytes.

CONCLUSIONS

The results indicate that lymphocytes and EBV latently infected B cells can survive the normal storage conditions for RBC.

A novel source of viable peripheral blood mononuclear cells from leukoreduction system chambers

BACKGROUND

Buffy coats are becoming less available as a source of research-grade peripheral blood mononuclear cells (PBMNCs). Therefore, alternative sources of these cells were investigated.

STUDY DESIGN AND METHODS

PBMNCs isolated from the cells retained in leukoreduction system chambers (LRSCs) and those eluted from white blood cell filters were compared. From LRSCs (1.88 +/- 0.40) x 10(9) PBMNCs (n = 13) versus (0.43 +/- 0.15) x 10(9) PBMNCs were isolated from leukofilter eluates (LFEs, n = 8; p < 0.0001).

RESULTS

Cells from LRSCs and LFEs produced similar numbers of burst-forming unit-erythroid, colony-forming unit (CFU)-granulocyte-macrophage, and CFU-granulocyte-erythrocyte-monocyte-macrophage-megakaryocyte colonies. The percentages of cells positive for CD3, CD4, CD8, CD14, CD19, and CD56 in the PBMNCs isolated from LRSCs and LFEs were indistinguishable. Cells isolated from LRSCs expressed higher levels of CD69 and CD25 in reaction to staphylococcal enterotoxin B than the cells isolated from LFEs. The source of cells affected neither the yield and purity of immunomagnetically isolated CD3+ cells, CD14+ cells, and CD56+ cells nor the function of T cells, natural killer cells, and in vitro matured dendritic cells (DCs). DC yield from LRSC-derived CD14+ cells, however, was higher.

CONCLUSION

LRSCs are a novel source of fully functional PBMNCs that can replace the more traditional sources of research-grade cellular products.