The cytomegalovirus-"safe" blood product: is leukoreduction equivalent to antibody screening?

Viral hepatitis in haemophilia: historical perspective and current management

The introduction of clotting factor concentrates has substantially improved the lives of people with clotting factor deficiencies. Unfortunately, the transmission of blood-borne viral infections through these plasma-derived products led to a huge epidemic of human immunodeficiency virus and viral hepatitis in people with haemophilia (PWH). In a significant proportion of PWH exposed to these viruses, the ensuing decades-long chronic infection resulted in excess morbidity and mortality. Fortunately, developments in the safety of blood products, as well as vaccination and highly effective antiviral treatments have improved the prospects of PWH. The present article reviews the background of the viral hepatitis epidemic in PWH, the natural history of hepatitis B and C infections and their long-term management.

Review of current transfusion therapy and blood banking practices

Transfusion Medicine is a dynamically evolving field. Recent high-quality research has reshaped the paradigms guiding blood transfusion. As increasing evidence supports the benefit of limiting transfusion, guidelines have been developed and disseminated into clinical practice governing optimal transfusion of red cells, platelets, plasma and cryoprecipitate. Concepts ranging from transfusion thresholds to prophylactic use to maximal storage time are addressed in guidelines. Patient blood management programs have developed to implement principles of patient safety through limiting transfusion in clinical practice. Data from National Hemovigilance Surveys showing dramatic declines in blood utilization over the past decade demonstrate the practical uptake of current principles guiding patient safety. In parallel with decreasing use of traditional blood products, the development of new technologies for blood transfusion such as freeze drying and cold storage has accelerated. Approaches to policy decision making to augment blood safety have also changed. Drivers of these changes include a deeper understanding of emerging threats and adverse events based on hemovigilance, and an increasing healthcare system expectation to align blood safety decision making with approaches used in other healthcare disciplines.

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.

Efforts Toward Elimination of Infectious Agents in Blood Products

The US blood supply has never been safer. This level of safety depends on a multifaceted approach including blood donor screening, sensitive infectious disease testing, and good manufacturing practice. However, risks remain for transfusion-transmitted infections due to bacterial contamination of platelets and emerging diseases. Thus, ongoing improvements in screening and testing are required. Newer pathogen reduction technologies have shown promise in further ameliorating the safety of the blood supply.

Thrombocytopenia and Critical Care Medicine

Platelet transfusions play an important role in the treatment of critically ill patients. Like any blood component, however, there are various aspects of platelet transfusion therapy that need be considered by the intensivist. These include the proper dose and type of platelet component to infuse, as well as the route and method of administration. Methods to reduce the volume of the transfused platelets, for example, must ensure that the infused platelets will be functional and viable, posttransfusion. Treatment and diagnosis of the HLA alloimmunized recipient can pose a serious challenge to the clinician and an obstacle to adequate platelet therapy. An ICU patient for whom an adequate posttransfusion platelet increment cannot be achieved is at great risk of suffering a fatal hemorrhage. The ICU physician should be aware of the techniques used in modern transfusion practice to avoid having to deal with this complication. Adverse reactions to platelet transfusion include not only serologic ones, but those related to febrile and allergic complications, as well as infectious complications. The latter group includes diseases caused by infection with cytomegalovirus, bacteria, and a cadre of viruses including HIV and hepatitis. The clinical approach to thrombocytopenia in the ICU will be covered in some detail in an effort to review many of the conditions associated with recipient thrombocytopenia, including ITP, TTP, dilutional thrombocytopenia, DIC, surgery, HELLP syndrome, and drug-induced thrombocytopenia. Unfortunately the treatment approaches traditionally used are not always derived from evidence-based studies. This review covers many of these topics in an attempt to help physicians become better able to manage thrombocytopenia in the ICU and thus provide the best transfusion therapy for their patients.

Cytomegalovirus transmission in pediatric renal transplant recipients during the window period

We report two CMV naïve children who received deceased donor renal transplants from a CMV IgG-negative single donor. CMV IgG in both recipients and the donor were negative immediately prior to transplant. Both recipients had early recurrences of their original disease in their transplants, requiring multiple sessions of plasmapheresis. All blood products used were leukoreduced or CMV seronegative. A few days post-transplant, both recipients developed significant positive CMV viremia. Both required initiation of oral valganciclovir. Case 1 responded to oral valganciclovir only while the case 2 had a delayed response to it and hence required intravenous ganciclovir with good response. When checked retrospectively, CMV IgM in the donor was positive along with positive CMV DNA PCR from the white cells. Here we describe a very unusual scenario of CMV transmission in two pediatric renal transplant recipients from a single donor during the CMV window period.

Utilization management in the blood transfusion service

The scope of activity of the Blood Transfusion Service (BTS) makes it unique among the clinical laboratories. The combination of therapeutic and diagnostic roles necessitates a multi-faceted approach to utilization management in the BTS. We present our experience in utilization management in large academic medical center.

Cytomegalovirus (CMV) seroprevalence in Japanese blood donors and high detection frequency of CMV DNA in elderly donors

BACKGROUND

The current prevalence of cytomegalovirus (CMV) in Japan and the risk of CMV transfusion transmission are unknown in the era of seronegative leukoreduced blood components.

STUDY DESIGN AND METHODS

We measured CMV-specific immunoglobulin (Ig)M and IgG in 2400 samples of whole blood collected from 12 groups of blood donors categorized by sex and age at 10-year intervals from their teens to their 60s. We also tested for CMV DNA using polymerase chain reaction in the cellular fractions of all samples.

RESULTS

We found that 76.6% of blood donors were CMV seropositive. The seroprevalences among donors in their 20s and 30s were 58.3 and 73.3%, respectively. We detected CMV DNA in the cellular fraction of 4.3% of samples from donors in their 60s and in 1.0% of samples from donors younger than 60 years. None of the 562 seronegative samples was DNA positive. Furthermore, 14% of DNA-positive samples also contained DNA in the plasma fraction, and two of five such samples were derived from donors in their 60s. Leukoreduced plasma components derived from donations with CMV DNA in plasma samples also contained a relevant amount of CMV DNA.

CONCLUSION

The seroprevalence of CMV among Japanese blood donors of child-bearing age has not changed over the past 15 years. Latent CMV becomes reactivated more frequently among elderly donors than among younger donors. A proportion of them have free CMV DNA in their plasma fraction, which could not be diminished by leukoreduction. The risk of transfusion-transmitted CMV infection in blood with plasma CMV DNA should be determined.

Seroprevalence of cytomegalovirus among some voluntary blood donors at the 37 military hospital, accra, ghana

SUMMARY BACKGROUND

Cytomegalovirus (CMV) is one of the most significant pathogens infecting immunosuppressed individuals. CMV is transmissible through transfusion of blood components.

AIM

The goal of this study was to determine the seroprevalence of antibodies to CMV among blood donors seen at the 37 Military Hospital Blood Transfusion Unit, (MHBTU) Accra, Ghana.

METHODS

The seroprevalence of antibodies specific for CMV was tested using CMV IgG/IgM particle agglutination test kit and ELISA.

RESULTS

Of the 264 blood donors, 18 were negative and 246 were positive for CMV IgG antibodies, giving an overall CMV prevalence rate of 93.2%. None of the 264 blood donors was positive for CMV IgM antibodies. About 96% of the donors aged between 30 to 39 years were seropositive for CMV, as against 91.9% in those aged 20-29 years, 88.6% in 40 to 49 years, 75.0% (3 out of 4) in 50 to 59 years, and 100% (1 out 1) in 60-69 years. There was no statistically significant difference (P>0.05) in the CMV IgG status in different age groups. The blood donors comprised largely of male donors (236 out of 264), making sex comparisons statistically undesirable. However, all the female (n=28) donors were positive for CMV IgG.

CONCLUSION

Since about 93% of blood donors at the MHBTU are seropositive for CMV, it would be very useful to screen blood donors in Ghana for CMV to identify the very few CMV-seronegative blood donors, and maintain an inventory of them for use as donors.

Pathogen inactivation/reduction of platelet concentrates: turning theory into practice

Background  Pathogen reduction technology (PRT) has been proven to reduce the residual risk of transmission of infectious agents. Reduction of various contaminating bacteriae, viruses and parasites by few to several log steps and efficiency to prevent GVHD has been shown. Aim  To evaluate and compare advantages and disadvantages of PRT available for practical application in platelets. Materials and Methods  PRT for the treatment of platelets is currently offered by two formats: Amotosalen (INTERCEPT, Cerus, Concord, CA, USA) and vitamin B2 (Mirasol, Caridian, Denver, USA). Results from different studies and our own experiences with the two techniques are compared and discussed. Results and Discussion  For both technologies, different groups of investigators have shown acceptable in-vitro results with respect to functional and storage data for platelets stored for up to 5 days after production and before transfusion. Initial clinical studies showed no inferiority of the treated platelets in comparison to untreated controls in thrombocytopenic patients. However for both techniques a tendency towards lower CCI has been reported, which may be more pronounced in the platelets treated with the Intercept process. For introduction of PRT many countries require not only CE mark but licensing with the respective authorities since treatment for pathogen reduction is regarded as creating a 'new' blood product. With respect to a platelet loss during pathogen reduction it seems recommendable to increase the lower limit of platelet content of the product to 2.5 × 1011. Particularly for the Intercept system, where a considerable amount of platelets is lost in the purification of the product from Amotosalen, a change in the production process to increase the platelet yield may be necessary. Data from our group show a tendency for improved functional and storage parameters for platelets treated with the Mirasol process. Compared to conventional manufacturing of platelets by apheresis or pooling of buffy coats, pathogen reduction requires additional labour, space, and quality control. Shelf life of platelets is limited in most countries because of the risk of bacterial contamination (in Germany presently to 4 days). A prolongation to 5 or more days after pathogen reduction seems feasible but remains a topic for future studies. Conclusion  Results of in vitro and clinical studies of pathogen reduced platelets are promising. Larger clinical trials will help to determine whether PRT proves to be beneficial (reduction of transmission of infections, less alloimmunisation) and overall cost effective (bearing in mind that additional costs may be compensated for by omission of gamma irradiation and potential longer shelf life).

Defining the risks for cytomegalovirus infection and disease after solid organ transplantation

Cytomegalovirus continues to be one of the most clinically significant infections after solid organ transplantation. Classic definitions of patients at high risk for infection and tissue-invasive disease are focused on recipient-donor serostatus, type of organ transplanted, and overall level of immunosuppression. However, recent trends in clinical practice call for a reevaluation of cytomegalovirus infection risks after solid organ transplantation. Indeed, whereas early-onset cytomegalovirus infection is usually controlled by antiviral prophylaxis with ganciclovir and derivatives, delayed- and late-onset cytomegalovirus infection can develop after the completion of a course of preventive therapy. In addition, indirect effects of cytomegalovirus infection may occur as a result of persistent low-level viremia. Suboptimal dosing of antiviral drugs due to specific drug toxicities may result in the development of ganciclovir-resistant cytomegalovirus disease. The relationship between organ allograft rejection and cytomegalovirus infection and disease has been recognized for some time. Transplantation of increasing numbers of extended-criteria donor organs increases the risk of delayed graft function and acute rejection, prompting the use of more intensive immunosuppression. In addition, the trend to spare long-term exposure to calcineurin inhibitors has contributed to a resurgence in the use of polyclonal T-cell induction immunosuppressive agents, which may reduce host anticytomegalovirus immunity. We discuss the current trends in solid organ transplantation that provide a foundation for defining risks for cytomegalovirus infection and disease, including identification of patients who would benefit from more aggressive cytomegalovirus monitoring and prevention strategies.

Why implement universal leukoreduction?

The improvement of transfusion medicine technology is an ongoing process primarily directed at increasing the safety of allogeneic blood component transfusions for recipients. Over the years, relatively little attention had been paid to the leukocytes present in the various blood components. The availability of leukocyte removal (leukoreduction) techniques for blood components is associated with a considerable improvement in various clinical outcomes. These include a reduction in the frequency and severity of febrile transfusion reactions, reduced cytomegalovirus transfusion-transmission risk, the reduced incidence of alloimmune platelet refractoriness, a possible reduction in the risk of transfusion-associated variant Creutzfeldt-Jakob disease transmission, as well as reducing the overall risk of both recipient mortality and organ dysfunction, particularly in cardiac surgery patients and possibly in other categories of patients. Internationally, 19 countries have implemented universal leukocyte reduction (ULR) as part of their blood safety policy. The main reason for not implementing ULR in those countries that have not appears to be primarily concerns over costs. Nonetheless, the available international experience supports the concept that ULR is a process that results in improved safety of allogeneic blood components.

Is White Blood Cell Reduction Equivalent to Antibody Screening in Preventing Transmission of Cytomegalovirus by Transfusion? A Review of the Literature and Meta-Analysis

The question whether the use of cytomegalovirus (CMV)-seronegative versus white blood cell (WBC)-reduced blood components is equally efficacious in preventing transfusion-acquired CMV infection remains unresolved. A total of 829 recipients of CMV-seronegative components were followed in 11 studies, and a total of 878 recipients of WBC-reduced components were followed in 12 studies. Twelve (1.45%) of 829 recipients of CMV-seronegative components and 24 (2.73%) of 878 recipients of WBC-reduced components developed CMV infection in these studies. Among bone marrow transplant (BMT) recipients, the risk of CMV infection was, respectively, 1.63% (11/674) and 3.01% (21/697). Four of 7 controlled studies of CMV-seronegative components and 1 of 3 controlled studies of WBC-reduced components indicated benefit from these special components compared with CMV-unscreened/non-WBC-reduced components. One of 3 controlled studies indicated benefit from CMV-seronegative components, as compared with WBC-reduced components. Across a subset of studies whose results were integrated in a meta-analysis, CMV-seronegative or WBC-reduced components were virtually equivalent to each other when they were compared with CMV-unscreened/non-WBC-reduced components. CMV-seronegative components were associated with a 93.1% reduction in the risk of CMV infection; WBC-reduced components were associated with a 92.3% reduction in risk (summary odds ratio [OR] = 0.069; 95% confidence interval [CI], 0.037-0.128; P < .05; and summary OR = 0.077; 95% CI, 0.031-0.190; P < .05, respectively). However, across 3 studies that compared CMV-seronegative and WBC-reduced components to each other, CMV-seronegative components were associated with a 58% reduction in risk (summary OR = 0.42; 95% CI, 0.22-0.79; P < .05). Thus, a meta-analysis of the available controlled studies indicates that CMV-seronegative blood components are more efficacious than WBC-reduced blood components in preventing transfusion-acquired CMV infection.

Low propidium iodide intensity in flow cytometric white blood cell counting as a marker of cell destruction?

BACKGROUND

Residual white blood cells (WBC) in filtered blood products were investigated with flow cytometry. Frequently two distinct populations with different propidium iodide (PI) intensities can be found. The aim of this study was to specify a population with low PI intensity and discuss it as a marker of ongoing cell destruction and their possible impact on cytomegalovirus safety.

STUDY DESIGN AND METHODS

Buffy coat-depleted red blood cells were filtered with an in-line filtration set (LCR5, MacoPharma) after 4 hours (LCR5/4 hr) and 16 hours (LCR5/16 hr) of storage, and whole blood was filtered with a whole-blood filtration set (LST1, MacoPharma [LST1/4 hr]). The population with low PI intensity was sorted with a flow cytometer and prepared for transmission electron microscopy.

RESULTS

The absolute count obtained in the low-PI-intensity area before filtration was significantly different comparing LCR5/4 hr (11.5 x 10(6) +/- 6.84 x 10(6) and 0.12 x 10(6) +/- 0.1 x 10(6)/unit) and LCR5/16 hr (69.3 +/- 42.12 and 0.06 +/- 0.05; p < 0.002). By use of LST1/4 hr no difference was found compared to LCR5/4 hr after filtration (0.12 +/- 0.09 vs. 0.12 +/- 0.1), but a significant difference was found when comparing the results before filtration (1.25 +/- 0.41 vs. 11.5 +/- 6.84; p < 0.02). Electron microscopy revealed that the sorted population consisted of predominantly cell and nuclear fragments.

CONCLUSIONS

Events found in the low-PI-intensity area are not WBCs but partially degraded DNA coming from ongoing cell destruction during extended storage. Our results provide evidence that the absolute count of events found in the low-PI-intensity area can be used as a semiquantitative marker of WBC destruction.

Continuous cytomegalovirus seroconversion in a large group of healthy blood donors

BACKGROUND AND OBJECTIVES

Transmission of cytomegalovirus (CMV) to seronegative, immunocompromised recipients can cause serious and fatal complications. Although the seroprevalence of CMV is high, the risk of primary CMV infection among healthy blood donors has not yet been analysed in a large population.

MATERIALS AND METHODS

We developed an algorithm to determine the rate of CMV seroconversion in an overall cohort of 24,260 subjects who donated 176,474 blood units during an 11-year observation period.

RESULTS

We detected CMV seroconversion in all relevant age groups (18-60 years) with an overall seroconversion rate of 0.55% per year. Both CMV seroconversion and seroprevalence occurred more frequently in female donors (P = 0.02 and P < 0.001, respectively). We identified 30-35-year-old blood donors as the group with the highest rate of CMV seroconversion per year (1.33% vs. 0.46%; P < 0.0001).

CONCLUSIONS

We conclude that the risk of primary CMV infection is a continuous lifelong event and correlates with age and female gender.

Transfusion-transmitted cytomegalovirus infection after receipt of leukoreduced blood products

Leukoreduced blood products are reportedly comparable to cytomegalovirus (CMV)-seronegative products for the prevention of transfusion-transmitted CMV (TT-CMV) infection after stem cell (SC) transplantation. To determine if the incidence of TT-CMV was affected by the increasing use of leukoreduced blood products, we followed a prospective cohort of 807 CMV-seronegative SC transplant (SCT) recipients who underwent weekly surveillance using the pp65 antigenemia assay. The incidence of TT-CMV for 2 time periods was recorded: Period 1 (5/94-11/96), when only CMV-seronegative and/or filtered blood products were provided, and period 2 (12/96-2/00), when leukocyte-reduced platelets obtained by apheresis without filtration were also used. The incidence of TT-CMV was higher during period 2 (18/447, 4%) than period 1 (6/360, 1.7%) (P <.05); this was correlated with higher utilization of both filtered and apheresed products from CMV-positive donors in period 2. Multivariable analysis identified filtered red blood cell (RBC) units (but not apheresis platelet products) from CMV-positive donors as the primary predictor of TT-CMV: each additional filtered RBC unit was associated with a 32% increase in the odds for TT-CMV (95% confidence interval [CI]: 8%-61%, P =.006). Pre-emptive therapy with ganciclovir after detection of antigenemia prevented all but one case of CMV disease prior to day 100. CMV-seronegative products may thus be superior to leukoreduced products (particularly filtered RBCs) for the prevention of TT-CMV. In an era of "universal leukoreduction," the abandonment of CMV-seronegative inventories appears premature, particularly among populations at high risk of CMV disease that do not receive active surveillance.

Risks associated with transfusion of cellular blood components in Canada

We provide a comprehensive review of risks associated with allogeneic red blood cell and platelet transfusions in Canada. The review focuses on clinically symptomatic noninfectious transfusion risks (acute and delayed hemolytic, febrile nonhemolytic [FNHTR], allergic, volume overload, transfusion-related acute lung injury, graft-versus-host disease, and posttransfusion purpura) and the risk of clinically significant disease from transfusion-transmitted infections. Data sources include information from Canadian Blood Services, Héma-Québec, Health Canada, and the Québec Hemovigilance System as well as published information from research studies and international hemovigilance systems. We estimate that in 2000 the aggregate risk of potentially severe reactions (excluding FNHTR and minor allergic reactions) was 43.2 per 100000 red cell units (95% confidence interval [CI]: 38.7-48.1), affecting 337 recipients, and 125.7 per 100000 platelet pools of 5 units (95% CI: 100.8-154.9), affecting 88 recipients. The most frequent potentially severe outcomes for red cell transfusion were hemolytic reactions and volume overload and for platelet transfusion were major allergic reactions and bacterial contamination. The current risk of human immunodeficiency virus and hepatitis C virus transmission is approximately 1 in 4 million and 1 in 3 million units, respectively. These estimates are useful for decisions concerning transfusion therapy, the informed consent process, and for evaluating efficacy of interventions to reduce risk.

Early primary immune response against erythrocytes: a case report

BACKGROUND

Primary immune response against red blood cell (RBC) antigens often takes weeks or months to be detected. In previous reports, for children receiving multiple units of blood components, ranging from five to 81 units, the elapsed time between the first RBC transfusion and antibody detection ranged from 18 to 78 days. Cytomegalovirus (CMV) is sometimes associated with immunohaematologic findings and may modulate immune response.

CASE REPORT

A 24-week-old male infant with interstitial pneumonia and hepatitis because of CMV developed an RBC auto antibody and two RBC alloantibodies: anti-Jka, detected in tube 11 days after a single RBC transfusion, and anti-K, detected only in papain gel test 18 days later.

CONCLUSION

As anti-Jka is not a naturally occurring antibody, this is the most rapid primary immune response against an RBC antigen after a single RBC transfusion ever described, in the youngest child ever described.

Perioperative blood transfusion therapy in pediatric patients

In general, transfusion guidelines for non-neonatal pediatric patients are similar to those for adults. However, some differences do exist and certain precautions may be necessary particularly in the setting of massive transfusions. We review these differences as they apply to general pediatric surgery outside of the neonatal period, with respect to the transfusion of red blood cells (RBCs), platelets, fresh-frozen plasma (FFP), and cryoprecipitate. We include a discussion of the indications for transfusion and practical considerations such as dosing and administration. Finally, we briefly review the use of directed donations and specialized (irradiated, CMV seronegative) blood components.

The risk of transfusion-acquired CMV infection in seronegative solid-organ transplant recipients receiving non-WBC-reduced blood components not screened for CMV antibody (1984 to 1996): experience at a single Canadian center

BACKGROUND

The use of CMV-safe cellular blood components has been recommended for CMV-sero- negative recipients of CMV seronegative (R-D-) solid- organ transplants.

STUDY DESIGN AND METHODS

The incidence of CMV infection in 281 CMV-seronegative patients receiving renal, heart, heart-lung, lung, and liver transplants at our center between January 1984 and October 1996 was studied. The blood components that these patients received were neither WBC reduced nor screened for CMV antibody.

RESULTS

One hundred thirty-one of 154 (85.1%) patients receiving organs from CMV-seropositive donors (R-D+) developed CMV infection compared with three cases of presumptive transfusion-acquired (TA) CMV infection in 127 R-D- recipients (2.4%) (relative risk, 36.0; 95% CI, 11.8-110.4). The organ-specific incidence of TA CMV infection in R-D- patients was as follows: renal, 0 of 57 (0%); heart, 0 of 29 (0%); heart-lung and/or lung, 1 of 6 (16.7%); and liver, 2 of 20 (10%). There was no significant difference in the transfusion requirements of CMV-infected and -uninfected R-D- patients. False-positive results were often (40%) observed when posttransfusion serum samples were used for determination of the organ donor CMV serostatus.

CONCLUSION

The low risk of TA CMV infection observed in transplant patients who received standard blood components in our study should be considered when evaluating the efficacy of programs that provide CMV-safe blood components for this population.

High incidence of Epstein-Barr virus, cytomegalovirus and human herpesvirus 6 infections in children with cancer

BACKGROUND

A prospective single-center study was performed to study infection with lymphotropic herpesviruses (LH) Epstein-Barr virus (EBV), cytomegalovirus (CMV) and human herpesvirus 6 (HHV-6) in children with cancer.

METHODS

The group of 186 children was examined for the presence of LH before, during and 2 months after the end of anticancer treatment. Serology of EBV and CMV was monitored in all children, serology of HHV-6 and DNA analysis of all three LH was monitored in 70 children.

RESULTS

At the time of cancer diagnosis (pre-treatment), there was no difference between cancer patients and age-matched healthy controls in overall IgG seropositivity for EBV (68.8% vs. 72.0%; p = 0.47) and CMV (37.6% vs. 41.7%; p = 0.36). During anticancer therapy, primary or reactivated EBV and CMV infection was present in 65 (34.9%) and 66 (35.4%) of 186 patients, respectively, leading to increased overall post-treatment IgG seropositivity that was significantly different from controls for EBV (86.6% vs. 72.0%; p = 0.0004) and CMV (67.7% vs. 41.7%; p < 0.0001). Overall pre-treatment IgG seropositivity for HHV-6 was significantly lower in patients than in controls (80.6% vs. 91.3%; p = 0.0231) which may be in agreement with Greaves hypothesis of protective effect of common infections in infancy to cancer development. Primary or reactivated HHV-6 infection was present in 23 (32.9%) of 70 patients during anticancer therapy leading to post-treatment IgG seropositivity that was not significantly different from controls (94.3% vs. 91.3%; p = 0.58). The LH infection occurred independently from leukodepleted blood transfusions given. Combination of serology and DNA analysis in detection of symptomatic EBV or CMV infection was superior to serology alone.

CONCLUSION

EBV, CMV and HHV-6 infections are frequently present during therapy of pediatric malignancy.

The effect of leukocyte-reduction method on the amount of human cytomegalovirus in blood products: a comparison of apheresis and filtration methods

This study examined the effectiveness of 3 leukocyte-reduction (LR) methods in depleting the residual level of cytomegalovirus (CMV) in blood products measured by quantitative polymerase chain reaction (QA-PCR). At 2 locations over 3 allergy seasons, apheresis platelets and whole blood were collected from 52 healthy CMV seropositive subjects having an elevated titer of CMV DNA (median = 2400 genome equivalents [GE]/mL) resulting in 32 evaluable LR apheresis platelets, 31 filtered platelets from whole blood, and 31 filtered red blood cells (RBCs) from whole blood. Leukoreduction by apheresis and filtration resulted in substantial reduction of detectable CMV DNA levels with 99.9% of the LR products expected to have less than 500 GE/mL of CMV DNA. No difference was found between methods (P = .52). CMV genomic leukocyte subset localization was determined by QA-PCR of fluorescence-activated cell sorter (FACS)-sorted peripheral blood from 20 seropositive subjects (n = 10 &gt; 100 GE/mL, n = 10 QA-PCR negative). CMV was detected in monocyte (13 of 20) and granulocyte (3 of 20) fractions. Presence of competent virus in QA-PCR positive (&gt; 100 GE/mL) peripheral blood samples was verified with 4 of 19 subjects positive in shell vial assay, and 8 of 18 positive for CMV gene products (messenger RNA). We observed a seasonal DNAemia variation in seropositive subjects. CMV seropositive subjects (n = 45) entered into longitudinal monitoring in March/April 1999 were QA-PCR negative at baseline. Subjects converted to a positive QA-PCR coincident with increased seasonal allergen levels (Norfolk 15 of 18 evaluable in 43.4 ± 9.48 days; Denver, 16 of 23 evaluable in 96 ± 26.3 days). These data demonstrate effective reduction of CMV load by LR during periods of DNAemia in CMV seropositive subjects.