Finding
Red blood cell (RBC) transfusion (chronic or acute transfusion) is essential for the medical management of the complications of SCD.
Paper
Transfusion management of patients with sickle cell disease: the continuing dilemma
Abstract
T his issue of TRANSFUSION includes two articles that highlight some of the remaining issues related to transfusion support for patients with sickle cell disease (SCD) in two very dichotomous settings, varying dramatically in terms of their depth of resources. On one extreme, Tournamille and colleagues from France report their findings evaluating patients with SCD for partial C status using molecular testing methods. They conclude that this technologically sophisticated testing is needed to optimally prevent alloimmunization. At the other end of the resource spectrum, Natukunda and colleagues provide an overview of transfusion management for patients with SCD in Uganda, with specific data on alloimmunization in their patient population. As the reader will find, these articles portray very different approaches to transfusion management of the same disease, in large part because of the differences in resource availability. It is likely that some portion of this journal’s readership has available resources that are either at one of these extremes or some place in the middle, spanning the gamut between the extremes that these authors represent. Taken together, these articles emphasize the medical management decisions that must be made to optimally utilize the available resources in the best interest of patient care. One of the most perplexing aspects of caring for patients with SCD is the fact that a single gene mutation can result in a spectrum of disease severity and manifestations. Hemoglobin S, the hallmark of SCD, is due to a single b-globin gene mutation. Patients with SCD may have relatively mild disease with occasional complications requiring hydration, pain medications, episodic transfusion, and uncommon hospitalization. In contrast, the same gene mutation in other patients results in severe disease with life-threatening complications, requiring regular transfusions, numerous hospitalizations, and even surgical interventions. For these severely affected patients, the disease and its often escalating complications become an obstacle for accomplishing desired life goals. Despite advances in therapeutic options and improvement in comprehensive health care with a focus on preventive care, there is no reliable predictor for severity of SCD. If there were a marker to predict which patients were at the highest risk for the most severe complications such as acute chest syndrome, multiorgan failure syndrome, or end-stage renal disease, these particularly highrisk patients could be preferentially counseled to consider progenitor cell transplantation. Without such a marker, it is difficult to consider the risks of transplantation in a patient who has not yet had numerous complications, but the patient who has already had numerous complications may no longer be the optimal transplant candidate. Thus, this variability of disease severity and the lack of a prognostic or predictive indicator contribute to the difficulties of medical management and, consequently, impact transfusion management. Not only does the disease vary in severity, but the need for transfusion and the immune response to transfusion vary as well. Red blood cell (RBC) transfusion (chronic or acute transfusion) is essential for the medical management of the complications of SCD. Because of the risk of alloimmunization and potentially severe hemolytic transfusion reactions, providing compatible blood to meet the needs of patients with SCD is one of the most difficult challenges confronting transfusion services and donor centers. Alloimmunization rates in patients with SCD in the United States have been well documented. In 12 reports reviewed by Garratty, the frequency of alloantibodies ranged from 8% to 35% of transfused patients with a mean and median of 25%. The cause of this high incidence of alloimmunization is probably multifactorial, although one contributing factor is clearly the disparity in antigen frequencies in patients and donors. The majority of patients with SCD are of African descent, whereas the majority of blood donors in the United States are white. Natukunda and coworkers report an alloimmunization rate of only 6.1% in Ugandan patients with SCD, which may reflect a more homogeneous population of patients and donors or the fact that the transfusion volumes and episodes were low, limiting antigen exposure. Similar to the United States, anti-E and anti-C were among the most commonly encountered antibodies in the Uganda study. The immune response to transfusion in patients with SCD is unpredictable and poorly understood. Some patients may produce only a single antibody specificity despite exposure to multiple alloantigens in repeated transfusions, while others may produce a spectrum of alloantibody specificities that become increasingly complex with each subsequent transfusion episode. Although the explanation for this variable response to TRANSFUSION 2010;50:2-4.
Authors
K. King, R. S. Shirey
Journal
Transfusion