Transfusion-Associated Graft-Versus-Host Disease

How I manage neonatal thrombocytopenia

Although neonatal thrombocytopenia (platelet count < 150×10(9) /l) is a common finding in hospital practice, a careful clinical history and examination of the blood film is often sufficient to establish the diagnosis and guide management without the need for further investigations. In preterm neonates, early-onset thrombocytopenia (<72h) is usually secondary to antenatal causes, has a characteristic pattern and resolves without complications or the need for treatment. By contrast, late-onset thrombocytopenia in preterm neonates (>72h) is nearly always due to post-natally acquired bacterial infection and/or necrotizing enterocolitis, which rapidly leads to severe thrombocytopenia (platelet count<50×10(9) /l). Thrombocytopenia is much less common in term neonates and the most important cause is neonatal alloimmune thrombocytopenia (NAIT), which confers a high risk of perinatal intracranial haemorrhage and long-term neurological disability. Prompt diagnosis and transfusion of human platelet antigen-compatible platelets is key to the successful management of NAIT. Recent studies suggest that more than half of neonates with severe thrombocytopenia receive platelet transfusion(s) based on consensus national or local guidelines despite little evidence of benefit. The most pressing problem in management of neonatal thrombocytopenia is identification of safe, effective platelet transfusion therapy and controlled trials are urgently needed.

Stored red blood cell viability is maintained after treatment with a second-generation S-303 pathogen inactivation process

BACKGROUND

Transfusion-transmitted infections and immunologic effects of viable residual lymphocytes remain a concern in red blood cell (RBC) transfusion. Pathogen reduction technologies for RBC components are under development to further improve transfusion safety. S-303 is a frangible anchor-linker-effector with labile alkylating activity and a robust pathogen reduction profile. This study characterized the viability of RBCs prepared with a second-generation S-303 process and stored for 35 days.

STUDY DESIGN AND METHODS

This was a two-center, single-blind randomized, controlled, crossover study in 27 healthy subjects. S-303 (test) or control RBCs were prepared in random sequence and stored for 35 days, at which time an aliquot of radiolabeled RBCs was transfused. The 24-hour recovery, RBC life span, and in vitro metabolic and viability variables were analyzed.

RESULTS

The mean 24-hour RBC recovery and hemolysis of test RBCs were similar to control RBCs and were consistent with the Food and Drug Administration (FDA) guidance for RBC viability. The mean differences in life span and median life span (T(50) ) of circulating test RBCs were 13.7 and 6.8 days, while the mean difference in the area under the curve of surviving RBCs was 1.38%, in favor of control RBCs. There were no clinically relevant abnormal laboratory values after the infusion of test RBCs. All crossmatch assays of autologous S-303 RBCs were nonreactive.

CONCLUSIONS

RBCs prepared using the S-303 pathogen inactivation process were physiologically and metabolically suitable for transfusion after 35 days of storage, met the FDA guidance criteria for 24-hour recovery, and did not induce antibody formation.

Very low birth weight infants qualifying for a 'late' erythrocyte transfusion: does giving darbepoetin along with the transfusion counteract the transfusion's erythropoietic suppression?

OBJECTIVE

Red blood cell (RBC) transfusions can suppress erythropoiesis. On this basis, RBC transfusions administered to very low birth weight (VLBW) neonates potentially render them more likely to qualify for a subsequent transfusion.

STUDY DESIGN

We hypothesized that 'late' (>14 days after birth) RBC transfusions given to VLBW neonates result in a decrease in reticulocyte count persisting for at least 7 to 10 days. We also hypothesized that a single dose of darbepoetin given along with the transfusion would have the opposite effect, increasing the reticulocyte count for at least 7 to 10 days. To test this, we conducted a single-centered randomized trial with 20 VLBW neonates who, according to our transfusion guidelines, qualified for a late transfusion.

RESULT

VLBW infants about to receive a late RBC transfusion were randomized (1:1) to also receive vs not receive (controls) a single subcutaneous dose of darbepoetin (10 μg kg(-1)). Reticulocyte counts diminished significantly in the controls (a drop of 85±62 × 10(3) μl(-1) (mean±s.d.) at 7 to 10 days), but increased significantly in the darbepoetin recipients (an increase of 177±120 × 10(3) μl(-1) at 7 to 10 days, P<0.0001). At 7 to 10 days after the transfusion, hematocrits of the controls were 8.1±4.9 points above their pre-transfusion values and of the darbepoetin group were 12.4±2.7 points above their pre-transfusion values (P=0.033).

CONCLUSION

This was a limited-scope, single-centered, randomized trial intended to pilot-test a new concept in neonatal transfusion practice. Namely, we tested whether a late RBC transfusion suppressed reticulocytosis and whether a concomitant single dose of darbepoetin counteracted that suppression. Using the pilot data presented in this study, larger trials can now be designed to address meaningful clinical outcomes such as transfusion avoidance using this approach.

Red blood cell transfusion in critically ill children: a narrative review

OBJECTIVE

To review the pathophysiology of anemia, as well as transfusion-related complications and indications for red blood cell (RBC) transfusion, in critically ill children. Although allogeneic blood has become increasingly safer from infectious agents, mounting evidence indicates that RBC transfusions are associated with complications and unfavorable outcomes. As a result, there has been growing interest and efforts to limit RBC transfusion, and indications are being revisited and revamped. Although a so-called restrictive RBC transfusion strategy has been shown to improve morbidity and mortality in critically ill adults, there have been relatively few studies on RBC transfusion performed in critically ill children.

DATA SOURCES

Published literature on transfusion medicine and outcomes of RBC transfusion. STUDY SELECTION, DATA EXTRACTION, AND SYNTHESIS: After a brief overview of physiology of oxygen transportation, anemia compensation, and current transfusion guidelines based on available literature, risks and outcomes of transfusion in general and in critically ill children are summarized in conjunction with studies investigating the safety of restrictive transfusion strategies in this patient population.

CONCLUSIONS

The available evidence does not support the extensive use of RBC transfusions in general or critically ill patients. Transfusions are still associated with risks, and although their benefits are established in limited situations, the associated negative outcomes in many more patients must be closely addressed. Given the frequency of anemia and its proven negative outcomes, transfusion decisions in the critically ill children should be based on individual patient's characteristics rather than generalized triggers, with consideration of potential risks and benefits, and available blood conservation strategies that can reduce transfusion needs.

A strategic approach to the problems of providing rhesus D-negative blood transfusion in geographic areas with low RhD negativity: a Nigerian perspective

In contrast to the white prevalence, the frequency of rhesus D (RhD) negativity in the Nigerian population ranges from less than 1% to about 6% in the different ethnic population groups across the country. Consequently, there is often a severe scarcity of RhD-negative blood in Nigeria, leading to undue delay in transfusing RhD-negative patients. This situation has led to the prolongation of hospital stays as well as increased morbidity and mortality in affected patients. The problem is compounded by the general unavailability of donor RhD-negative blood, which is partially related to a suboptimal national blood transfusion service. This situation has thus relegated the responsibilities of donor recruitment and blood collection to individual hospital blood banks. This has led to the necessity of finding a variety of ways to mitigate the daunting problem of the provision of RhD-negative donor blood in Nigeria. In this article, we review the roles, advantages, and disadvantages of various methods including the use of autologous donations, D(u) testing, inter-blood bank transfers, voluntary RhD-negative donor recall, family donations, and cryopreservation to ameliorate the problem. The real need is nonetheless to optimize the functional capacity of the Nigerian National Blood Transfusion Service.

Improving cellular therapy for primary immune deficiency diseases: recognition, diagnosis, and management

More than 20 North American academic centers account for the majority of hematopoietic stem cell transplantation (HCT) procedures for primary immunodeficiency diseases (PIDs), with smaller numbers performed at additional sites. Given the importance of a timely diagnosis of these rare diseases and the diversity of practice sites, there is a need for guidance as to best practices in management of patients with PIDs before, during, and in follow-up for definitive treatment. In this conference report of immune deficiency experts and HCT physicians who care for patients with PIDs, we present expert guidance for (1) PID diagnoses that are indications for HCT, including severe combined immunodeficiency disease (SCID), combined immunodeficiency disease, and other non-SCID diseases; (2) the critical importance of a high degree of suspicion of the primary care physician and timeliness of diagnosis for PIDs; (3) the need for rapid referral to an immune deficiency expert, center with experience in HCT, or both for patients with PIDs; (4) medical management of a child with suspicion of SCID/combined immunodeficiency disease while confirming the diagnosis, including infectious disease management and workup; (5) the posttransplantation follow-up visit schedule; (6) antimicrobial prophylaxis after transplantation, including gamma globulin administration; and (7) important indications for return to the transplantation center after discharge. Finally, we discuss the role of high-quality databases in treatment of PIDs and HCT as an element of the infrastructure that will be needed for productive multicenter clinical trials in these rare diseases.

Does point of care prothrombin time measurement reduce the transfusion of fresh frozen plasma in patients undergoing major surgery? The POC-OP randomized-controlled trial

Background

Bleeding is a frequent complication during surgery. The intraoperative administration of blood products, including packed red blood cells, platelets and fresh frozen plasma (FFP), is often live saving. Complications of blood transfusions contribute considerably to perioperative costs and blood product resources are limited. Consequently, strategies to optimize the decision to transfuse are needed.

Bleeding during surgery is a dynamic process and may result in major blood loss and coagulopathy due to dilution and consumption. The indication for transfusion should be based on reliable coagulation studies. While hemoglobin levels and platelet counts are available within 15 minutes, standard coagulation studies require one hour. Therefore, the decision to administer FFP has to be made in the absence of any data. Point of care testing of prothrombin time ensures that one major parameter of coagulation is available in the operation theatre within minutes. It is fast, easy to perform, inexpensive and may enable physicians to rationally determine the need for FFP.

Methods/Design

The objective of the POC-OP trial is to determine the effectiveness of point of care prothrombin time testing to reduce the administration of FFP. It is a patient and assessor blind, single center randomized controlled parallel group trial in 220 patients aged between 18 and 90 years undergoing major surgery (any type, except cardiac surgery and liver transplantation) with an estimated blood loss during surgery exceeding 20% of the calculated total blood volume or a requirement of FFP according to the judgment of the physicians in charge. Patients are randomized to usual care plus point of care prothrombin time testing or usual care alone without point of care testing. The primary outcome is the relative risk to receive any FFP perioperatively. The inclusion of 110 patients per group will yield more than 80% power to detect a clinically relevant relative risk of 0.60 to receive FFP of the experimental as compared with the control group.

Discussion

Point of care prothrombin time testing in the operation theatre may reduce the administration of FFP considerably, which in turn may decrease costs and complications usually associated with the administration of blood products.

Trial registration

NCT00656396