The Use of Leukocyte-Reduced Blood Components

Leukodepleted blood components do not remove the potential for long-term transfusion-associated microchimerism in Australian major trauma patients

Despite the introduction of leukodepleted blood components, it has been shown that donor leukocyte engraftment (microchimerism) remains a long-term consequence of red blood cell (RBC) transfusion. The incidence of microchimerism may be affected by international disparities in blood processing methods or variations in transfusion practices. This study was conducted to determine the prevalence of microchimerism in Australian trauma patients. A secondary aim was to examine whether any patient complications correlated to the incidence of microchimerism. Australian trauma patients (n = 86) who had been transfused with red blood cell (RBC) units between 2000 and 2012 with an injury severity score (ISS) of greater than 15 were recruited. The prevalence of microchimerism was determined using genetic screening with a panel of insertion/deletion biallelic polymorphisms. The mean storage age of the transfused RBC units was 20 ± 8 days and the mean length of stay (LOS) in hospital was 40 ± 39 days. There were no significant associations in this study sample to bias for patient age, gender, number of transfused RBC units or ISS. Nine of the 55 (16.3%) patients transfused with non-leukodepleted blood components displayed an incidence of microchimerism. Of the 31 patients transfused with leukodepleted RBC units, 3 (9.6%) displayed an incidence of microchimerism. Therefore, despite the universal introduction of leukodepleted blood components in Australia, the prevalence of transfusion-associated microchimerism was found to be unchanged. Furthermore, half of the patients exhibiting microchimerism were recorded to have had splenic injury or required splenectomy at the time of transfusion.

Leucocyte depletion of perioperative blood transfusion does not affect long-term survival and recurrence in patients with gastrointestinal cancer

BACKGROUND

Perioperative red blood cell (RBC) transfusion may be associated with a poor prognosis in cancer surgery. Allogeneic leucocytes are assumed to play a causal role. This study evaluated the long-term effect of transfusion with leucocyte-depleted (LD) blood in patients with gastrointestinal cancer.

METHODS

The Transfusion Associated Complications = Transfusion Induced Complications? (TACTIC) study is a multicentre randomized controlled trial evaluating the short-term benefits of LD versus non-LD RBC transfusions. The present study evaluated 5-year survival and cancer recurrence among 512 patients with gastrointestinal cancer included in the TACTIC study.

RESULTS

Some 89.2 per cent of patients had a primary tumour and 79.7 per cent underwent surgery with curative intent; 243 patients received perioperative RBC transfusion (median 3 units). The 5-year overall survival rate of patients with any type of gastrointestinal cancer was 50.8 per cent in the LD group and 45.8 per cent in the non-LD group (P = 0.191). Corresponding 5-year disease-free survival rates were 60.0 and 56.6 per cent (P = 0.482), and recurrence rates 32.9 and 34.3 per cent (P = 0.864).

CONCLUSION

Leucocyte depletion is not associated with better long-term survival and lower recurrence rates in patients with gastrointestinal cancer.

Transfusion of leukoreduced red blood cells may decrease postoperative infections: two meta-analyses of randomized controlled trials

PURPOSE

To evaluate the efficacy and effectiveness of red blood cell leukoreduction in reducing postoperative infection, mortality and cancer recurrence, two meta-analyses of randomized controlled trials (RCTs) were conducted.

METHODS

A systematic search of the scientific literature was conducted. The pooled relative risk ratio (RR) of developing an adverse postoperative outcome with either leukoreduced or non-leukoreduced blood was calculated using a random effects model. To better estimate the efficacy of leukoreduction, a second analysis of transfused patients only was conducted.

RESULTS

Ten RCTs met inclusion criteria and eight provided separate data for patients randomized and transfused. The mean percentage of patients randomized but not transfused was 34%. For postoperative infection, the overall pooled RR was 0.76 [(95% confidence interval (CI): 0.54-1.08] for the "all patients randomized" analysis. For the "only patients transfused" analysis, the pooled RR became clinically and statistically significant (RR = 0.60 (95% CI: 0.38-0.93). For mortality, the pooled RR for the "all patients randomized" analysis was 0.71 (95% CI: 0.45-1.13) and 0.61 (95% CI: 0.36-1.04) for the "only patients transfused" analysis. When analyzing either all patients randomized or all patients transfused, there was no statistically significant difference in cancer recurrence rates (one study only).

CONCLUSION

We demonstrated that patients who were transfused leukoreduced red blood cells might benefit from a decrease in postoperative infections. A decrease in mortality may have been realized if more patients had been enrolled in the various randomized trials. Including all patients randomized, regardless of whether or not they were actually transfused diluted the observed clinical benefit of leukoreduction.

WBC reduction in cryopreserved RBC units

BACKGROUND

WBC reduction of blood components by filtration is widely practiced to decrease the incidence of alloimmunization. Freezing RBCs reduces the WBC load but is insufficient to achieve the currently recommended US limit of 5 x 10(6) cells per unit.

STUDY DESIGN AND METHODS

Blood units were WBC reduced by filtration or by buffy-coat (BC) removal and then frozen in the presence of a high-glycerol concentration. The count of residual WBCs was determined by flow cytometry after deglycerolization.

RESULTS

Without WBC reduction, the total number of WBCs present after freezing and thawing was 11.5 +/- 9.2 x 10(6) WBCs per unit (n = 18). Particulate residues from monocytes and neutrophils that were detected in the remaining cell populations were positive for CD66b, CD3, CD14, and CD41. Removal of 40 mL of BC at the time of blood collection lowered the number of WBCs after freezing and deglycerolization to 1.9 +/- 1.20 x 10(6) per unit (n = 11). Similar results were obtained when only 20 mL of BC was removed using a modified blood-bag design. Unfiltered RBC units that were stored for 15 days at 4 degrees C after BC removal contained fewer than 5 x 10(6) WBCs after deglycerolization. Units WBC reduced by filtration before freezing had no detectable WBCs after thawing and washing (n = 14) and did not contain particulate residues. Filtration after deglycerolization was effective in reducing the WBC count below 10(6), although some debris was still present.

CONCLUSION

RBC freezing alone will not reduce residual counts to recommended levels. However, initial removal of BC can provide an economical alternative to WBC filtration for cryopreserved units. Units that were not WBC reduced before freezing can be filtered after deglycerolization when needed.

Signs and symptoms associated with the transfusion of WBC-reduced RBCs and non-WBC-reduced RBCs in patients with anemia and HIV infection: results from the Viral Activation Transfusion Study

BACKGROUND

RBC transfusion is associated with fever and other reactions in some patients. The Viral Activation Transfusion Study randomly assigned patients to receive either unmodified or WBC-reduced RBCs and thus offered an opportunity to assess the effect of WBC-reduced RBCs on the incidence of transfusion reactions prospectively.

STUDY DESIGN AND METHODS

This prospective, randomized, double-blind, multicenter study compared prestorage WBC-reduced RBCs to unmodified RBCs in HIV-infected, CMV-seropositive, and transfusion-naive persons who required transfusions for anemia. Primary endpoints were survival and change in the plasma HIV RNA level at 7 days after transfusion. The incidence of transfusion reactions was prospectively evaluated.

RESULTS

The two groups had similar baseline characteristics and study endpoints; 3864 RBC units (median storage age, 9 days) were administered to 531 patients during 1745 transfusions. The most frequent signs reported were elevated temperature and hypotension. Subjects who reported fever within the week prior to transfusion were more likely to have an elevation in temperature associated with transfusion. The administration of RBCs that were less than 10 days old was associated with a marginal increase in the incidence of transfusion-associated temperature elevation among recipients of unmodified RBCs, but not among recipients of WBC-reduced RBCs. Caregivers reported fewer instances of both elevated temperature and hypotension than were identified by review of transfusion records.

CONCLUSIONS

The incidence of elevated temperature and hypotension associated with transfusion in this population was unexpectedly high. Use of WBC-reduced RBCs had no effect on the overall rates of elevated temperature or hypotension associated with transfusion of RBCs. The occurrence of a pre-existing fever was associated with a higher frequency of transfusion-associated elevated temperature.

Targeted approaches for the treatment of thrombocytopenia

Molecular targeting of novel therapies has the promise of inducing very specific biologic effects. In clinical hematology and oncology, molecular targeting of specific cell surface receptors with erythropoietin, G-CSF, or GM-CSF has been used to stimulate erythropoiesis and granulopoiesis, respectively. Although anemia and neutropenia can be corrected with targeted therapy, safe and effective treatment of thrombocytopenia remains an unmet medical need. While platelet transfusions still represent the standard of care for severe thrombocytopenia, there are several negative aspects associated with their use, including issues of availability, transient effectiveness, costs, adverse effects, negative perception by patients, and infection considerations. Despite extensive investigations of cytokines which act primarily on primitive levels of hematopoiesis, pharmacologic interventions to date have failed to elevate platelet counts in a reliable, highly effective, and well-tolerated fashion. Recombinant human interleukin-11 has been approved by the U.S. Food and Drug Administration for the treatment of chemotherapy-induced thrombocytopenia but has only modest efficacy and significant side effects. The identification of c-Mpl as the thrombopoietin receptor has opened new avenues for the therapeutic manipulation of thrombopoiesis. The development of specific c-Mpl ligands, including recombinant human thrombopoietin (rHuTPO), has allowed investigators to target this receptor for the treatment of chemotherapy-induced thrombocytopenia and other medical disorders characterized by extremely low platelet counts. As a potent stimulator of platelet production, rHuTPO has the potential to reduce the need for platelet transfusions and their attendant complications.

Bleeding risk and platelet transfusion refractoriness in patients with acute myelogenous leukemia who undergo autologous stem cell transplantation

Therapy for acute myelogenous leukemia can be complicated by alloimmunization to histocompatibility antigens (HLA), with resultant refractoriness to platelet transfusions. Autologous peripheral blood or bone marrow stem cell transplantation (referred here collectively as 'autoBMT') is emerging as a standard consolidative strategy in acute myelogenous leukemia (AML). We had noted life-threatening bleeding associated with platelet transfusion refractoriness following autoBMT; we therefore retrospectively analyzed 39 AML patients for this complication following BMT. All patients received high-dose chemoradiotherapy, followed by infusion of allogeneic sibling donor (n = 12, alloBMT) or autologous (n = 27, autoBMT) stem cells. HLA alloimmunization was assessed if patients were suspected of immune refractoriness to random donor platelet transfusions. Within 100 days of stem cell infusion, one of three alloBMT and six of 12 autoBMT recipients tested were HLA alloimmunized (not statistically significant, NS). Five of six HLA alloimmunized autoBMT patients experienced delayed bleeding, which contributed to their demise while still in remission (P < 0.001). Increased platelet requirements in HLA alloimmunized autoBMT recipients were observed between days 61 and 100 post-BMT, at a median of 211 platelet transfusions vs 0 in non-alloimmunized autoBMT patients (P < 0.01) and 17 in alloBMT patients. Our data suggest that platelet transfusion refractoriness, when associated with HLA alloimmunization, is a risk factor for increased platelet transfusion requirements, delayed bleeding, and poor outcome following autoBMT for AML.

How to improve transfusion medicine. A treating physician's perspective

As transfusion medicine becomes more complex, cooperative strategies are gaining increasing importance in relaying information to the treating physician and in incorporating the treating physician into the education and quality control processes. The broad domain of transfusion medicine is illustrated by the variety of disciplines involved in defining the use of products such as fresh frozen plasma and the newly released solvent-detergent-treated plasma, fibrin glue and highly purified fibrin sealant, and leukoreduced and irradiated blood products. Cooperative efforts among physicians and other personnel of multiple disciplines are essential to ensure appropriate use and continuous evaluation of blood products.

Transfusion and stem cell support in cancer treatment

Intensification of therapeutic regimens, improved patient survival, and advances in cytokine and cellular therapies have led to increasingly complex requirements for transfusion and stem cell support in cancer treatment. This article focuses on current and evolving issues in red blood cell, platelet, and granulocyte transfusion support, as well as measures to avoid increasingly important complications of transfusion therapy, such as alloimmunization, graft-versus-host disease, cytomegalovirus infection, and immunomodulation. Issues concerning current applications of hematopoietic stem cell transplantation and future prospects also are discussed.