Is Cytomegalovirus Testing of Blood Products Still Needed for Hematopoietic Stem Cell Transplant Recipients in the Era of Universal Leukoreduction?

Impact of cytomegalovirus (CMV) seroconversion pre-allogeneic hematopoietic cell transplantation on posttransplant outcomes

Cytomegalovirus (CMV) reactivation post-allogeneic hematopoietic cell transplantation (post-alloHCT) increases morbidity and mortality. We sought to determine the frequency of CMV seroconversion in patients pre-alloHCT and to investigate the impact on posttransplant outcomes. We retrospectively investigated 752 adult patients who underwent alloHCT at our center from January 2015 to February 2020 before the adoption of letermovir prophylaxis. CMV serology was assessed at consult and pretransplant. The cohort was divided into four groups based on pretransplant CMV seroconversion: negative to positive (Group 1), positive to negative (Group 2), consistently negative (Group 3), and consistently positive (Group 4). Eighty-nine patients (12%) had seroconverted from negative to positive, 17 (2%) from positive to negative, 151 (20%) were consistently seronegative, and 495 (66%) were consistently seropositive pretransplant. For the four CMV serostatus groups, cumulative incidence of CMV reactivation at 6 months posttransplant was 4.5%, 47.1%, 6.6%, and 76.6% for Groups 1, 2, 3, and 4, respectively (p < .0001). No differences between groups were seen regarding Grade III-IV acute graft-versus-host disease (GVHD) (p = .91), moderate/severe chronic GVHD (p = .41), or graft failure (p = .28). On multivariable analysis, there was no impact of CMV serostatus group on overall survival (p = .67), cumulative incidence of relapse (p = .83) or non-relapse mortality. alloHCT patients who demonstrate CMV seroconversion pretransplant from negative to positive have a very low risk of CMV reactivation posttransplant. The observed seroconversion may be due to passive CMV immunity acquired through blood products. Quantitative CMV immunoglobulin G/immunoglobulin M pretransplant may help differentiate between true seroconversion and passively transmitted CMV immunoglobulin.

What's in Your Transfusion? A Bedside Guide to Blood Products and Their Preparation

An understanding of the contents of blood products and how they are modified before transfusion will help any physician. This article will review five basic blood products and the five most common product modifications.

A Centre-Based Comparison of Double vs Single Prevention Strategy on Transfusion Transmitted-Cytomegalovirus in At-Risk Haemopoietic stem cell transplant Patients and a State Survey on CMV-Seronegative Ordering Practices

BACKGROUND AND OBJECTIVES

Universal leucocyte depletion reduces the risk of transfusion transmitted Cytomegalovirus; however, many clinicians still prescribe Cytomegalovirus seronegative units. Our retrospective study aims to confirm the low risk of transfusion transmitted Cytomegalovirus with leucocyte depletion alone and demonstrate the ongoing variability in Cytomegalovirus seronegative transfusion prescribing.

MATERIALS AND METHODS

Over a 9 year period (7/2009-7/2018), occurrences of transfusion transmitted Cytomegalovirus in Cytomegalovirus seronegative donor/recipient haemopoietic stem cell transplant pairs were compared at one allogeneic haemopoietic stem cell transplant centre providing Cytomegalovirus seronegative blood products and leucocyte depletion (double prevention) versus another providing leucocyte depletion only (single prevention). Retrospective chart audit identified patient demographics, blood product exposure and Cytomegalovirus infection by polymerase chain reaction. A separate audit examined Cytomegalovirus seronegative blood product ordering in a broader range of hospital types.

RESULTS

We identified 122 and 66 Cytomegalovirus negative donor/recipient haemopoietic stem cell transplant pairs using double and single transfusion prevention strategy respectively. Transfusion exposure to red cells and pooled platelets was similar, though more apheresis platelets were used in the double prevention group. Cytomegalovirus infection rate was 3 (2.4%) and zero in the double and single prevention groups respectively. Cytomegalovirus seronegative unit ordering was not limited to hospitals with obstetric or neonatal populations, suggesting ongoing reliance of Cytomegalovirus seronegative units outside this population.

CONCLUSION

The analysis suggests a double prevention strategy does not provide additional protection against transfusion transmitted Cytomegalovirus. There is ongoing variability in the acceptance of leucocyte depletion alone despite the low risk of Cytomegalovirus infection This article is protected by copyright. All rights reserved.

Cytomegalovirus seroprevalence among blood donors: a systematic review and meta-analysis

Background

Screening for cytomegalovirus (CMV)-specific antibodies is not routine in some settings. Thus, transfusion of blood products poses risks for susceptible individuals.

Objectives

To investigate the global pooled CMV seroprevalence among volunteer blood donors.

Methods

This systematic review and meta-analysis was performed according to PRISMA guidelines. The databases searched included Embase, Google Scholar, Medline, PubMed, Web of Science, and Cochrane Library. Data were extracted independently and analyzed using STATA version 11.

Results

The global seroprevalence of CMV IgG, CMV IgM, and both CMV IgM and IgG was 83.16% (95% confidence interval [CI]: 78.55–87.77%, I² = 99.5%), 13.77% (95% CI: 11.59–15.95%, I² = 98.8%), and 23.78% (95% CI: 10.50–37.06%, I² = 98.7), respectively.

Conclusion

The global seroprevalence of CMV was high among blood donors. Therefore, regular CMV screening should be conducted to identify CMV-seronegative blood donors.

Transfusion in Neonatal Patients: Review of Evidence-Based Guidelines

Transfusion of red blood cells, platelets, and fresh frozen plasma in neonatal patients has not been well characterized in the literature, with guidelines varying greatly between institutions. However, anemia and thrombocytopenia are highly prevalent, especially in preterm neonates. When transfusing a neonatal patient, clinicians must take into consideration physiologic differences, gestational and postnatal age, congenital disorders, and maternal factors while weighing the risks and benefits of transfusion. This review of existing literature summarizes current evidence-based neonatal transfusion guidelines and highlights areas of current ongoing research and those in need of future studies.

Transfusion-transmitted and community-acquired cytomegalovirus infection in seronegative solid organ transplant recipients receiving seronegative donor organs

Solid organ transplant (SOT) recipients who are cytomegalovirus (CMV) seronegative (R-) and receive seronegative donor (D-) organs have a small but currently unquantified risk of both transfusion-transmitted CMV (TT-CMV) and community-acquired CMV (CA-CMV). We retrospectively studied the incidence and clinical symptoms of TT-CMV (infection <1 year posttransplant) and CA-CMV (infection >1 year posttransplant) in a cohort of D-/R- adult and pediatric SOT recipients receiving leukoreduced blood products not screened for CMV seronegativity transplanted at our center between 2000 and 2011. CMV infection was defined as IgG seroconversion or detectable CMV antigenemia/DNAemia. Among 536 consecutive D-/R- recipients, 398 (81.8%) had adequate follow-up, and 231 (58%) received cellular blood products (total: 1626 red blood cell units, 470 platelet units) 30 days pretransplant to 90 days posttransplant. We observed no confirmed TT-CMV cases, but 14 CA-CMV cases (64% symptomatic) were seen. The estimated incidence rate of CA-CMV was higher in children (3.0/100 patient years) than adults (0.46/100 patient years, incident rate ratio of 6.52). The absence of TT-CMV over 11 years suggests neither seronegative blood products nor CMV DNA blood donor screening would provide significant incremental safety when blood is already leukoreduced. D-/R- SOT recipients, particularly children, have a significantly higher and ongoing risk of CA-CMV.

Transfusion-transmitted cytomegalovirus: behaviour of cell-free virus during blood component processing. A study on the safety of labile blood components in Switzerland

BACKGROUND

Nowadays, most blood products are leukocyte-reduced. After this procedure, the residual risk for transfusion transmitted cytomegalovirus (TT-CMV) is mostly attributed to cell-free viruses in the plasma of blood donors following primary infection or viral reactivation. Here, objectives are: 1) to study the behaviour of cell-free CMV through the blood component processing; 2) to determine the anti-CMV seroprevalence, the level of viremia, the window-period in blood donor population; and 3) to identify cases of TT-CMV in bone marrow transplant (BMT) recipients.

MATERIALS AND METHODS

Cell-free CMV was injected into blood bags originating from regular donors. Blood components were processed according to either the CompoSelect^® or the CompoFlow^® (Fresenius Kabi AG) techniques. Samples were analysed at each step for presence of virus DNA using quantitative polymerase chain reaction (PCR). The anti-CMV seroprevalence in our donor population was taken from our donor data system. The viremia was assessed in pooled plasmas samples from routine donations by quantitative PCR. Medical charts of 165 BMT anti-CMV seronegative recipients/anti-CMV seronegative donors who received CMV-unscreened blood products were reviewed.

RESULTS

Cell-free CMV passes without any decrease in viral load through all stages of blood processing. The anti-CMV seroprevalence was 46.13%. Four DNA positive samples out of 42,240 individual blood donations were identified (0.009%); all had low levels of viremia (range 11-255 IU/mL). No window-period donation was identified. No TT-CMV was found.

DISCUSSION

Cell-free CMV remains a concern with current blood component processing as it passes through all the processes. However, since low levels of CMV DNA were identified in the donations tested, and no BMT recipients had TT-CMV, the residual threat of TT-CMV after leukocyte reduction appears to be very low.

Risk of cytomegalovirus transmission by blood products after solid organ transplantation

Cytomegalovirus (CMV) infection and CMV disease are significant contributors to increased morbidity, mortality, and cost for immunocompromised solid organ transplant recipients. Although the most significant risk for CMV transmission is the CMV serological status of the transplant donor and recipient, exposure to blood products is another potential risk factor. Before the era of leukocyte reduction, CMV seronegative products were issued to reduce the risk of CMV transmission, thus rendering the products CMV safe. This approach requires maintenance of two inventories of blood products and continuous donor testing. Leukocyte-reduced cellular transfusion products are also considered CMV safe and are essentially universally available. To minimize the risk of CMV infection in transplant recipients, strategies include use of seronegative blood products or prestorage leukocyte reduction. However, no recent randomized prospective controlled trial directly compares the two CMV safety approaches for transplant recipients. Hence, current policy relies on historic trials and more recent observational studies. As a consequence, though generally considered equivalent approaches, preferred practice varies between centers. This review provides guidance to inform an acceptable practice approach.

AlloHSCT in paediatric ALL and AML in complete remission: improvement over time impacted by accreditation?

Allogeneic hematopoietic stem cell transplantation (alloHSCT) has become a well-established treatment option for many patients suffering from malignant and non-malignant diseases. In the past decade, high-resolution HLA-typing, remission surveillance, pre-emptive immune intervention, and standardisation in supportive care measures have substantially improved transplant outcomes. This retrospective study evaluated transplant procedures in 162 paediatric patients with acute lymphoblastic leukaemia (n = 124) or acute myeloid leukaemia (n = 38) who received their first alloHSCT in our institution over an 11-year period. We observed a significant reduction in risk of non-relapse mortality (NRM) over time (HR = 0.34, 95% CI 0.12-0.98; P = 0.05), the 4-year NRM estimate decreased from 20% in 2005-2008 to 7% in 2012-2016 (P = 0.02) and an increase in survival after relapse. There was no significant difference in patients who received a graft from a sibling, haplo, or an unrelated donor with regard to their overall survival (P = 0.45), event-free survival (P = 0.61), and non-relapse mortality (P = 0.19). Our data suggest that a specific transplant infrastructure with a highly experienced team in an accredited transplant centre likely contributes to better transplant outcomes for acute leukaemia patients in complete remission regardless of donor type.

Provision of cellular blood components to CMV-seronegative patients undergoing allogeneic stem cell transplantation in the UK: survey of UK transplant centres

OBJECTIVES

To identify current UK practice with regards to provision of blood components for cytomegalovirus (CMV)-seronegative, potential, allogeneic stem cell recipients of seronegative grafts.

BACKGROUND

Infection with CMV remains a major cause of morbidity and mortality after allogeneic stem cell transplantation (aSCT). CMV transmission has been a risk associated with the transfusion of blood components from previously exposed donors, but leucocyte reduction has been demonstrated to minimise this risk. In 2012, the UK Advisory Committee for the Safety of Tissues and Organs (SaBTO) recommended that CMV-unselected components could be safely transfused without increased risk of CMV transmission.

METHODS

We surveyed UK aSCT centres to establish current practice.

RESULTS

Fifteen adult and seven paediatric centres (75%) responded; 22·7% continue to provide components from CMV-seronegative donors. Reasons cited include the continued perceived risk of CMV transmission by blood transfusion, its associated morbidity and concerns regarding potential for ambiguous CMV serostatus in seronegative potential transplant recipients due to passive antibody transfer from CMV-seropositive blood donors, leading to erroneous donor/recipient CMV matching at transplant.

CONCLUSIONS

The survey demonstrated a surprisingly high rate (22.7%) of centres continuing to provide blood components from CMV-seronegative donors despite SaBTO guidance.

Survey on Transfusion-Transmitted Cytomegalovirus and Cytomegalovirus Disease Mitigation

CONTEXT

- Cytomegalovirus (CMV) can be transmitted by cellular blood products, leading to severe disease in immunosuppressed patients such as neonates and transplant recipients. To mitigate transfusion-transmitted CMV (TT-CMV), "CMV-safe" blood products (leukoreduced and/or CMV-seronegative) are transfused. Attempts to develop practice guidelines for TT-CMV mitigation have been limited by paucity of high-quality clinical trials.

OBJECTIVE

- To assess current TT-CMV mitigation strategies across medical institutions for specific at-risk populations.

DESIGN

- Supplemental questions regarding TT-CMV and CMV disease mitigation were added to a College of American Pathologists Transfusion Medicine (Comprehensive) Participant Survey in 2015, addressing whether a given institution provided CMV-safe products for 6 at-risk patient populations.

RESULTS

- Ninety percent (2712 of 3032) of institutions reported providing universally leukoreduced blood products. Among institutions without universal leukoreduction, 92% (295 of 320) provided leukoreduced products on the basis of clinical criteria. Eighty-three percent (2481 of 3004) of respondents reported having availability of CMV-seronegative products; however, wide variation in policies was reported governing CMV-seronegative product use. Among all respondents, less than 5% reported using CMV prophylaxis and monitoring in high-risk patient groups. Transplant centers reported higher rates of CMV prophylaxis (25% [97 of 394] solid organ) and monitoring (15% [59 of 394] solid organ) for CMV-negative transplant recipients.

CONCLUSIONS

- Universal leukoreduction is the primary strategy for mitigating TT-CMV. While most institutions have both CMV-seronegative and leukoreduced blood products available, consensus is lacking on which patients should receive these products. High-quality studies are needed to determine if CMV-seronegative and leukoreduced blood products are needed in high-risk patient populations.

Aged-associated cytomegalovirus and Epstein-Barr virus reactivation and cytomegalovirus relationship with the frailty syndrome in older women

Immunosenescence is an age-related reduction of immune system activity that can be associated with frailty. This study aimed to compare cytomegalovirus (CMV) and Epstein–Barr virus (EBV) reactivations (based on viremias) between young and elderly women who had a chronic CMV and/or EBV infection (i.e., an IgG⁺ serostatus) without an acute infection (i.e., an IgM⁻ serostatus), and among the elderly group categorized according to frailty status. DNA was extracted from plasma using standard protocols and serostatus was determined by enzyme-linked immunosorbent assay. Quantitative real-time polymerase chain reaction analyses for CMV and EBV were carried out and viral loads were determined. Among elderly women (n = 71), 59% were positive for CMV, in contrast to only 8% of young women (n = 73). Elderly women classified as frail, pre-frail, and non-frail presented 82%, 56%, and 48% positivity for CMV, respectively. Frequency and viral load were significantly higher in the elderly group vs. the young group (p < 0.0001 and p = 0.01, respectively) and in elderly with frailty vs. those without frailty (p = 0.007 and p = 0.03, respectively). The frequency of CMV reactivation presented odds ratios of 11.77 for aging and 6.13 for frailty, and relative risks of 5.39 for aging and 1.93 for frailty. EBV was detected in 30% of the elderly women and 15% of the young women (p = 0.04); however, the viral load did not significantly differ between the two age groups. The frequency of EBV reactivation presented odds ratios of 2.36 for aging and 2.90 for frailty, and relative risks of 1.96 for aging and 2.12 for frailty. However, no difference in EBV viral load among the frailty status subgroups was found. In conclusion, the frequency of CMV reactivation was associated with aging and ongoing frailty, whereas the frequency of EBV reactivation was associated only with aging.

Cytomegalovirus

Cytomegalovirus (CMV), the largest of the herpesviruses, causes a wide range of clinical syndromes, from asymptomatic infection to severe disease in immunocompromised hosts. Laboratory methods for diagnosis include molecular testing, antigenemia, culture, serology, and histopathology. Treatment of CMV infection and disease is indicated in selected immunocompromised hosts, and preventive approaches are indicated in high-risk groups. This chapter reviews the epidemiology, clinical aspects, and the laboratory diagnosis and management of CMV in immunocompromised hosts.

Transfusion-transmitted CMV infection - current knowledge and future perspectives

Transmission of human cytomegalovirus (CMV) via transfusion (TT-CMV) may still occur and remains a challenge in the treatment of immunocompromised CMV-seronegative patients, e.g. after stem cell transplantation, and for low birthweight infants. Measures to reduce the risk of TT-CMV have been evaluated in clinical studies, including leucocyte depletion of cellular blood products and/or the selection of CMV-IgG-negative donations. Studies in large blood donor cohorts indicate that donations from newly CMV-IgG-positive donors should bear the highest risk for transmitting CMV infections because they contain the highest levels of CMV-DNA, and early CMV antibodies cannot neutralise CMV. Based on this knowledge, rational strategies to reduce the residual risk of TT-CMV using leucoreduced blood products could be designed. However, there is a lack of evidence that CMV is still transmitted by transfusion of leucoreduced units. In low birthweight infants, most (if not all) CMV infections are caused by breast milk feeding or congenital transmission rather than by transfusion of leucoreduced blood products. For other patients at risk, no definitive data exist about the relative importance of alternative transmission routes of CMV compared to blood transfusion. As a result, only the conduction of well-designed studies addressing strategies to prevent TT-CMV and the thorough examination of presumed cases of TT-CMV will achieve guidance for the best transfusion regimen in patients at risk.

Transfusion Reactions

Transfusion reactions are common occurrences, and clinicians who order or transfuse blood components need to be able to recognize adverse sequelae of transfusion. The differential diagnosis of any untoward clinical event should always consider adverse sequelae of transfusion, even when transfusion occurred weeks earlier. There is no pathognomonic sign or symptom that differentiates a transfusion reaction from other potential medical problems, so vigilance is required during and after transfusion when a patient presents with a change in clinical status. This review covers the presentation, mechanisms, and management of transfusion reactions that are commonly encountered, and those that can be life-threatening.

Survey of Institutional Policies for Provision of "CMV-Safe" Blood in Ontario

OBJECTIVES

Debate continues on whether leukoreduction alone (LR) is sufficiently similar to leukoreduced cellular products drawn from cytomegalovirus (CMV)-seronegative (SN) donors to minimize the risk of transfusion-transmitted CMV (TT-CMV). We sought to determine the policy, inventory, and practice landscape of the province for TT-CMV mitigation.

METHODS

A web-based survey was distributed to hospitals in Ontario by Canadian Blood Services to collect data on their policies with respect to TT-CMV prevention.

RESULTS

TT-CMV mitigation practices varied by patient population, hospital size, and region. Smaller institutions remain committed to dual prevention, whereas academic hospitals favor a single-measure approach. Although smaller institutions attempt to align their policies with leadership sites, emulation is often inaccurate. The demands for SN products also appear to be significantly lower than the current screening practices of Canadian Blood Services.

CONCLUSIONS

Standardization is lacking on practices to prevent TT-CMV. Although there are barriers to harmonizing practices, the apparent shift to policies acknowledging LR as a sufficient protection is likely to continue.

Assessment of a cytomegalovirus serology dual-testing strategy in hematopoietic stem cell transplant recipients

BACKGROUND

Accurate determination of recipient cytomegalovirus (CMV) serostatus before allogeneic hematopoietic stem cell transplantation (HSCT) is critical, as it is the most important predictor of post-transplant CMV infection and remains associated with non-relapse mortality. The purpose of this study was to assess a recipient dual-testing strategy before HSCT.

METHODS

CMV serologic testing was performed before allogeneic HSCT using 2 different assays: reference laboratory (RL) and American Red Cross (ARC). In all cases, blood samples were obtained for RL testing either before ARC testing (median 130 days before HSCT [range 12-2594]) or at the same time (median 25 days before HSCT [range 8-129]). The results of serologic testing were correlated with CMV viremia post HSCT.

RESULTS

Of 287 recipients evaluated, 76 (26.5%) had discordant results, of which 74 (97.4%) tested RL-/ARC+. Ten had RL and ARC testing performed on simultaneously obtained samples, 3 of which (30%) were discordant (3 [100%] RL-/ARC+). Acute myeloid leukemia and receipt of blood product transfusion in the interval between testing were associated with RL-/ARC+ discordance. Correlation with viremia after HSCT suggested that RL-/ARC+ discordance was caused by detection of anti-CMV immunoglobulin transferred in transfused blood products and reduced specificity of the ARC assay.

CONCLUSION

CMV-seronegative hematopoietic stem cell transplant recipients may be misclassified as seropositive if testing is performed after receipt of blood products or when using assays optimized for sensitivity at the expense of specificity. This misclassification may negatively affect post-HSCT outcomes for individual patients and studies that rely on accurate CMV serology reporting.

Infectious diseases in allogeneic haematopoietic stem cell transplantation: prevention and prophylaxis strategy guidelines 2016

Infectious complications after allogeneic haematopoietic stem cell transplantation (allo-HCT) remain a clinical challenge. This is a guideline provided by the AGIHO (Infectious Diseases Working Group) of the DGHO (German Society for Hematology and Medical Oncology). A core group of experts prepared a preliminary guideline, which was discussed, reviewed, and approved by the entire working group. The guideline provides clinical recommendations for the preventive management including prophylactic treatment of viral, bacterial, parasitic, and fungal diseases. The guideline focuses on antimicrobial agents but includes recommendations on the use of vaccinations. This is the updated version of the AGHIO guideline in the field of allogeneic haematopoietic stem cell transplantation utilizing methods according to evidence-based medicine criteria.

Modifications to Blood Components: When to Use them and What is the Evidence?

Blood component modifications can be performed by the hospital blood bank for select clinical indications. In general, modification of blood components increases costs and may delay availability of the blood component because of the additional time required for some modification steps. However, the benefit of blood product modification may outweigh these concerns. Common modifications include leukoreduction, irradiation, volume reduction, splitting, and washing. Modification availability and selection practice may vary from hospital to hospital. In this article, available blood component modifications are described along with the benefits, drawbacks, and specific clinical indications supporting their use.

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.

Risks associated with red blood cell transfusions: potential benefits from application of pathogen inactivation

BACKGROUND

Red blood cell (RBC) transfusion risks could be reduced if a robust technology for pathogen inactivation of RBC (PI-RBCs) were to be approved.

MATERIALS AND METHODS

Estimates of per-unit and per-patient aggregate infectious risks for conventional RBCs were calculated; the latter used patient diagnosis as a determinant of estimated lifetime exposure to RBC units. Existing in vitro data for the two technologies under development for producing PI-RBCs and the status of current clinical trials are reviewed.

RESULTS

Minimum and maximum per-unit risk were calculated as 0.0003% (1 in 323,000) and 0.12% (1 in 831), respectively. The minimum estimate is for known lower-risk pathogens while the maximal estimate also includes an emerging infectious agent (EIA) and endemic area Babesia risk. Minimum and maximum per-patient lifetime risks by diagnosis grouping were estimated as 1.5 and 3.3%, respectively, for stem cell transplantation (which includes additional risk for cytomegalovirus transmission); 1.2 and 3.7%, respectively, for myelodysplastic syndrome; and 0.2 and 44%, respectively, for hemoglobinopathy.

DISCUSSION

There is potential for PI technologies to reduce infectious RBC risk and to provide additional benefits (e.g., prevention of transfusion-associated graft-versus-host disease and possible reduction of alloimmunization) due to white blood cell inactivation. PI-RBCs should be viewed in the context of having a fully PI-treated blood supply, enabling a blood safety paradigm shift from reactive to proactive. Providing insurance against new EIAs. Further, when approved, the use of PI for all components may catalyze operational changes in blood donor screening, laboratory testing, and component manufacturing.

Transfusion in CMV seronegative T-depleted allogeneic stem cell transplant recipients with CMV-unselected blood components results in zero CMV transmissions in the era of universal leukocyte reduction: a U.K. dual centre experience

OBJECTIVES

To establish rates of cytomegalovirus (CMV) transmission with use of CMV-unselected (CMV-U), leukocyte-reduced blood components transfused to CMV-seronegative patient/CMV-seronegative donor (CMV neg/neg) allogeneic stem cell transplantation (SCT) recipients including those receiving T-depleted grafts.

BACKGROUND

CMV infection remains a major cause of morbidity following SCT. CMV-seronegative SCT recipients are particularly at risk of transfusion transmitted CMV (TT-CMV) and until recently they have received blood components from CMV-seronegative donors with significant resource implications. Although leukocyte reduction of blood components is reported to minimise risk of TT-CMV, its efficacy in high-risk situations, such as in T-depleted transplant recipients, is unknown.

METHODS

We retrospectively analysed the incidence of TT-CMV in CMV neg/neg allogeneic SCT recipients transfused with CMV-U, leukocyte-reduced blood components in two transplantation centres in the UK. Patients were monitored for CMV infection by weekly CMV polymerase chain reaction testing. Leukocyte reduction of blood components was in accordance with current UK standards.

RESULTS

Among 76 patients, including 59 receiving in vivo T-depletion, no episodes of CMV infection were detected. Patients were transfused with 1442 CMV-unselected, leukocyte-reduced components, equating to 1862 donor exposures.

CONCLUSIONS

Our findings confirm the safety of leukocyte reduction as a strategy in preventing TT-CMV in high-risk allogeneic SCT recipients.