Guideline:Blood transfusion therapy in β-thalassemia major

Note This clinical guideline is a wiki conversion of the corresponding chapter of the Thalassaemia International Federation (TIF) Guidelines for the Clinical Management of Thalassaemia, 2nd Edition (ISBN: 978-9963-623-70-9). It is provided here for an evaluation of the conversion procedure, only, and no part of it should be reproduced or stored elsewhere. The newest edition of the original document, with exclusive copyright TIF, is available for free download here.

Goals of Blood Transfusion Therapy
Appropriate goals of transfusion therapy and optimal safety of transfused blood are the key concepts in the protocol for routine administration of red blood cells to patients with thalassemia. The major goals are:
 * 1) Maintenance of red cell viability and function during storage, to ensure sufficient transport of oxygen
 * 2) Use of donor erythrocytes with a normal recovery and half-life in the recipient
 * 3) Achievement of appropriate hemoglobin level
 * 4) Avoidance of adverse reactions, including transmission of infectious agents

Quality and Adequacy of Blood
To safeguard the health of the transfusion recipient, including patients with thalassemia, blood should be obtained from carefully selected regular voluntary, non-remunerated donors and should be collected, processed, stored and distributed, in the context of dedicated, quality assured national blood transfusion centers. Nationally developed legislation-based on EU, Council of Europe, North American, World Health Organization (WHO) or other international directives, recommendations or relevant laws and taking into account national needs, resources and prevalence of infectious agents, should safeguard the quality of blood transfusion services. Blood donation practices, donor selection (e.g., through questionnaire) and product screening constitute some of the most important strategies that contribute to the safety and adequacy of blood. For more information on EU directives visit and. On recommendations of the Council of Europe visit, while on WHO guidelines and American Standards visit and  content, respectively.

Transfusion Therapy in Thalassemia
This chapter will address five of the most common questions related to the transfusion therapy of patients with thalassemia major:
 * 1) When to initiate transfusion therapy and whom to transfuse
 * 2) How blood is processed for effective and safe transfusion therapy in thalassemia major
 * 3) Is there an optimal hemoglobin (Hb) level for effective transfusion
 * 4) Do transfusion requirements affect the success of iron chelation therapy
 * 5) What are the most serious transfusion related (TR) reactions (common and less frequent)

To decide who to transfuse, the following should be included in the investigations:
 * 1) Confirmed laboratory diagnosis of thalassemia major
 * 2) Laboratory criteria: Hb < 7 g/dl on 2 occasions, > 2 week apart (excluding all other contributor causes such as infections) or
 * 3) Laboratory and clinical criteria, including:
 * Hb > 7 g/dl with:
 * Facial changes
 * Poor growth
 * Fractures, and
 * Extramedullary hematopoiesis

Recommended blood product
Patients with &beta;-thalassaemia major should receive leukoreduced packed red blood cells with a minimum hemoglobin content of 40 g. Reduction to 1 x 106 or fewer leukocytes per unit (mean counts as low as 0.05 x 106 are achievable) (Council of Europe, RE 2006) is considered the critical threshold for the elimination of adverse reactions attributed to contaminating white cells (see Table 1, below) and for preventing platelet alloimmunisation.

Methods for leukoreduction
Pre-storage filtration of whole blood is the preferred method for leukoreduction. The delay in filtration (4–8 hours) may allow some phagocytosis of bacteria (e.g., Yersinia enterocolitica). This method of leucocyte removal offers high-efficiency filtration and provides consistently low residual leukocytes in the processed red cells and high red cell recovery. Packed red cells are obtained by centrifugation of the leukoreduced whole blood. Pre-transfusion, laboratory filtration refers to the filtration at the blood bank laboratory of packed red cells, prepared from donor whole blood. Bedside filtration refers to the packed red cell unit which is filtered at the bedside, at the time of transfusion. This method,although equally sensitive to those above, may not allow optimal quality control because the techniques used for bedside filtration may be highly variable.

Blood products for special patient populations
Washed red cells may be beneficial for patients with thalassemia who have repeated severe allergic transfusion reactions. Saline washing of the donor product removes plasma proteins that constitute the target of antibodies in the recipient. Other clinical states that may require washed red cell products include immunoglobulin A (IgA) deficiency, in which the recipient’s preformed antibody to IgA may result in an anaphylactic reaction. Washing usually does not result in adequate leukocyte reduction and should not be used as a substitute for leukoreduction. Instead, washing should be used in conjunction with filtration. In addition, washing of red cell units may remove some erythrocytes from the transfusion product, and it is therefore valuable to monitor post-transfusion hemoglobin levels to ensure attainment of the targeted Hb level. Frozen (or cryopreserved) red cells is the component derived from whole blood in which red cells are frozen, preferably within 7 days of collection, using a cryopreservant and stored at -60&deg;C to -80&deg;C or below, based on the method used. These are used to maintain a supply of rare donor units for certain patients who have unusual red cell antibodies or who are missing common red cell antigens.

The Council of Europe is promoting an international network of rare blood donor units and may be contacted as follows:
 * Council of Europe - Point I
 * F67075 Strasbourg Cedex
 * France
 * Tel:  +33 3 88 41 2000
 * Fax:  +33 3 88 41 2781
 * E-mail: point_i@coe.fr
 * Internet: www.coe.fr

Red cells obtained by donor apheresis comprise two units of red cells collected from the same donor for transfusion of one patient is associated with reduction of donor exposures and consequently to a decreased risk (i) of transmission of infections, and (ii) of developing alloimmunisation and other transfusion-related complications.

Neocyte or young red cell transfusion may modestly reduce blood requirements. However, patients are exposed to a higher number of donors, with a consequent increase in cost, risk of transmission of infections, and risk of developing alloantibodies.

Storage of donor red cell units
The anticoagulant preservative solutions used in blood collection (see Table 2a) have been developed to prevent coagulation and to permit storage of red cells for a certain period of time. All of these solutions contain sodium citrate, citric acid and glucose, some of them may also contain adenine, guanosine and phosphate (e.g., CPD-A). When red cell concentrates are prepared, a considerable part of the glucose and adenine is removed with the plasma. If not compensated for in other ways, sufficient viability of the red cells can only be maintained if the cells are not over-concentrated. Normal CPD-adenine red cell concentrate should therefore not have a hematocrit (Hct) above 0.70 on average (CoE Re 2006). Newly developed additive solutions, however, allow maintenance of red cell viability even if more than 90% of the plasma is removed, as they contain considerably higher levels of the necessary nutrients (see Table 2b). The use of glucose and adenine is necessary for the maintenance of red blood cell post-transfusion viability, phosphate may be used to enhance glycolysis, and other substances (e.g., mannitol, citrate) may be used to prevent in vitro hemolysis. Sodium chloride or di-sodium phosphate may be used to give the additive solution a suitable osmotic strength. Thus the introduction of additives such as AS-1, AS-3, AS-5 (see Table 2b) has permitted considerably longer storage of red cells for up to 42 days. The maximum duration of storage (expiry date) as noted on each unit varies with the type of preparation (concentration of cells, formula of anticoagulant, use of additive suspension fluid, etc.) and should be determined for each type on the basis of achieving a mean 24 hours post-transfusion survival of at least 75% of the transfused red cells. The hemoglobin oxygen release function (which is extremely important in thalassemia major) is impaired during storage due to progressive loss of 2,3-biphosphoglycerate (2,3-BPG, previously known as 2,3-diphosphoglycerate, DPG). Although, the storage time of whole blood in CPDA-1 for example is 35 days (CoE Re 2006), after 10 days of storage all 2,3–BPG is lost (CoE Re 2006). In the case of additives such as the ones mentioned above (see Table 2b), although storage times up to 42 days are advocated and high levels of ATP are maintained up to the 28th day of storage, 2,3-BPG and P50 values may not be fully maintained even for this length of time. In addition, information about the red cell half-life in the recipient after prolonged storage of donor blood is limited. Taking into consideration all the above and in view of the fact that in thalassemia major, decreased recovery and a shortened red cell half-life may increase transfusion requirements and as a consequence the rate of transfusional iron loading. the current practice is to use red cells stored in additive solutions for less than two weeks, and in CPD-A for even less days – as fresh as possible. In patients with cardiac disease and in small children, particular attention should be paid to the increased volume resulting from additive solutions. In general, for all patients, the lower hematocrit of red cell units containing newer additive solutions should be taken into consideration when calculating the annual rate of transfusional iron loading (see Tables 2a & 2b).

Table 2 - Solutions used in blood preservation. [Source: Brecker M, ed Technical Manul, 14th ed. Bethesda, MD: American Association of Blood Banks, 2003: 162]

Compatibility testing
Development of one or more specific red cell antibodies (alloimmunisation) is a common complication of chronic transfusion therapy. Thus it is important to monitor patients carefully for the development of new antibodies and to eliminate donors with the corresponding antigens. Anti-E, anti-C and anti-Kell alloantibodies are the most common. However, 5–10% of patients present with alloantibodies against rare erythrocyte antigens or with warm or cold antibodies of unidentified specificity. It is recommended that: If new antibodies appear, they must be identified so that in future blood lacking the corresponding antigen(s) can be used. A complete and detailed record of antigen typing, red cell antibodies and transfusion reactions should be maintained for each patient, and should be readily available when and if the patient is transfused at a different center. Transfusion of blood from first-degree relatives should be avoided because of the risk of developing antibodies that might adversely affect the outcome of a later stem cell transplant.
 * Before embarking on transfusion therapy, patients should have extended red cell antigen typing that includes at least C, c, E, e and Kell, in order to help identify and characterise antibodies in case of later immunisation
 * All patients with thalassaemia should be transfused with ABO and Rh(D) compatible blood. In addition, the use of blood that is also matched for the C, E and Kell antigens is highly recommended in order to avoid alloimmunisation against these antigens. Some centres use even more extended antigen matching.
 * Before each transfusion it is necessary to perform a full crossmatch and screen for new antibodies.

Transfusion programs
The recommended treatment for thalassaemia major involves lifelong regular blood transfusions, usually administered every two to five weeks, to maintain the pre-transfusion haemoglobin level above 9–10.5 g/dl. This transfusion regimen promotes normal growth, allows normal physical activities, adequately suppresses bone marrow activity in most patients, and minimizes transfusional iron accumulation. A higher target pre-transfusion hemoglobin level of 11–12 g/dl may be appropriate for patients with heart disease or other medical conditions and for those patients who do not achieve adequate suppression of bone marrow activity at the lower hemoglobin level. Although shorter intervals between transfusions may reduce overall blood requirements, the choice of interval must take into account other factors such as the patient’s work/school schedule and other lifestyle issues. The decision to initiate lifelong transfusion therapy should be based on a definitive diagnosis of ‚-homozygous thalassemia. This diagnosis should take into account the molecular defect, the severity of anemia on repeated measurements, the level of ineffective erythropoiesis, and clinical criteria such as failure to thrive or bone changes. The initiation of regular transfusion therapy for severe thalassemia usually occurs in the first two years of life. Some patients with milder forms of thalassemia who only need sporadic transfusions in the first two decades of life may later need regular transfusions because of a falling hemoglobin level or the development of serious complications. The risk of alloimmunization appears to be greater in patients who begin transfusion therapy after the first few years of life (see Table 3). Presence of alloantibodies and autoantibodies (see below) may severely compromise transfusion therapy in patients with thalassaemia intermedia, for example, who receive their first transfusions in adolescence or later. Recommendations regarding the volume of transfused red cells are complicated by the use of different anticoagulant preservatives and additive solutions. For CPD-A units with a haematocrit of approximately 75%, the volume per transfusion is usually 10–15 ml/kg, administered over 3–4 hours. Units with additive solutions may have lower haematocrits in the range of 60–70%, and consequently larger volumes with a higher haematocrit level are needed to administer the same red cell mass (see Table 4). For most patients, it is usually easier to avoid these differences in red cell concentration by ordering a certain number of units (e.g. one or two) rather than a particular volume of blood. Younger children may require a fraction of a unit to avoid under- or over-transfusion. Patients with cardiac failure or very low initial hemoglobin levels should receive smaller amounts of red cells at slower rates of infusion.

The post-transfusion Hb should not be greater than 14–15 g/dl and should be monitored occasionally to allow assessment of the rate of fall in the hemoglobin level between transfusions in evaluating the effects of changes in the transfusion regimen, the degree of hypersplenism, or unexplained changes in response to transfusion. Although erythrocytapheresis, or automated red cell exchange, has been shown to reduce net blood requirements and thus the rate of transfusional iron loading, its use may be limited due to a two- to three-fold increase in donor blood utilisation, increased (i) costs, (ii) risk of transmission of infections and (iii) development of alloimmunization. A careful record of transfused blood should be maintained for each patient, including the volume or weight of the administered units, the hematocrit of the units or the average hematocrit of units with similar anticoagulant-preservative solutions, and the patient’s weight. With this information, it is possible to calculate the annual blood requirements as volume of transfused blood and pure red cells (hematocrit 100%) per kg of body weight. The latter (RBC at 100% hematocrit) when multiplied with 1.08, the estimated amount of iron per ml of RBC yields an approximate value for the amount of transfusional iron that the patient receives per kilogram of body weight in a year. Figure 1 shows a detailed example of how the daily rate of iron loading (mg/(kg*day)) is calculated, and Table 5 shows the relationship between the annual transfusion requirements and the daily rate of iron loading at two common hematocrits for donor blood. The rate of transfusional iron loading may be very important in choosing the appropriate dose of an iron chelator. For example, the recommended dose of the chelator deferasirox is based in part on the daily or annual rate of transfusional iron loading.

Knowing the annual transfusion requirements is also valuable in identifying changes that may constitute important evidence of hypersplenism or accelerated destruction of donor red cells. Specific guidelines for consideration of splenectomy in the presence of increasing transfusion requirements are difficult to establish because of a lack of information on the hematocrit levels of the transfused blood in earlier recommendations and uncertainty with regard to long-term consequences of splenectomy, including sepsis and thrombosis. Moreover, the decision to proceed to splenectomy must take into consideration the individual patient’s ability to control iron stores at a given level of transfusional iron loading. Nevertheless, as the annual transfusion requirements rise above 200 ml/(kg*a) of pure red cells, splenectomy should be considered as a potential strategy to reduce the rate of iron loading.

Adverse reactions
Blood transfusion exposes the patient to a variety of risks. Thus, it is vital to continue to improve blood safety and to find ways of reducing transfusion requirements and the number of donor exposures. Adverse events (see Table 7) associated with transfusion include:
 * Non-hemolytic febrile transfusion reactions were common in past decades, but have been dramatically reduced by leucoreduction, especially pre-storage leucoreduction, which sharply reduces cytokine accumulation and leucocyte alloimmunisation. In the absence of effective leucoreduction, patients experiencing such reactions should be given antipyretics before their transfusions. Since fever may accompany a haemolytic transfusion reaction or the administration of a unit with bacterial contamination, these causes should always be considered in a patient who develops fever during administration of red cells.

Hemolytic reactions in these patients can still be avoided by
 * Allergic reactions are usually due to plasma proteins and range from mild to severe. Milder reactions include urticaria, itching and flushing, and they are generally mediated by IgE. More severe reactions, such as stridor, bronchospasm, hypotension or other symptoms of anaphylaxis may occur, especially in patients with IgA deficiency and anti-IgA antibodies. Occasional mild allergic reactions often can be prevented by the use of antihistamines or corticosteroids before transfusion. Recurrent allergic reactions can be markedly reduced by washing the red cells to remove the plasma. Patients with IgA deficiency and severe allergic reactions may require blood from IgA-deficient donors.
 * Acute hemolytic reactions begin within minutes or sometimes hours of beginning a transfusion and are characterized by the abrupt onset of fever, chills, lower back pain, dyspnea, hemoglobinuria and shock. These unusual reactions most commonly arise from errors in patient identification or blood typing and compatibility testing. The risk of receiving the wrong blood is greater for a patient with thalassemia who travels to another center or is admitted to a hospital not familiar with his/her case and medical history.
 * the use of optimal methods for identifying the patients and labeling of the sample when blood is obtained for crossmatch
 * proper linkage of the sample to the donor unit in the blood bank
 * adherence to standard protocols for screening for antibodies and carrying out the necessary full crossmatching of donor units
 * use of multiple patient identifiers before transfusing the blood.

In many transfusion units, two staff members check the identification of the unit and the recipient prior to beginning the transfusion. If signs and symptoms suggest an acute hemolytic reaction, the transfusion should be stopped immediately and intravenous fluids should be administered to maintain intravascular volume. Diuretics may help to preserve renal function. Disseminated intravascular coagulation (DIC) may require additional measures such as heparin. The identification of the patient and the donor unit should be re-checked. The blood bank should also be alerted to the possibility of an undetected alloantibody. Some patients have also been treated with rituximab, but the effectiveness of its use in this situation is presently not well defined. Autoimmune hemolytic anemia occurs more frequently in patients who begin transfusion therapy later in life, and should be carefully considered before instituting transfusion therapy for teenagers and adults with thalassemia intermedia. specific anti-neutrophil or anti-HLA antibodies. This complication is characterized by dyspnea, tachycardia, fever and hypotension during or within six hours of transfusion. Hypoxemia is present and the chest radiograph shows bilateral infiltrates typical of pulmonary edema, although there is no reason to suspect volume overload. Management includes oxygen, administration of steroids and diuretics, and, when needed, assisted ventilation.
 * Delayed transfusion reactions usually occur 5–14 days after transfusion and are characterized by unexpected levels of anemia, as well as malaise and jaundice. These reactions may be due to an alloantibody that was not detectable at the time of transfusion or to the development of a new antibody. A sample should be sent to the blood bank to investigate the presence of a new antibody and to repeat cross-matching of the last administered unit(s).
 * Autoimmune hemolytic anemia is an extremely serious complication of transfusion therapy that usually but not always occurs in patients with alloantibodies. Even red cells from seemingly compatible units (i.e., those units that do not contain the antigen to which there is a known alloantibody) may demonstrate markedly shortened survival, and the hemoglobin concentration may fall well below the usual pre-transfusion level. Destruction both of the donor’s and the recipient’s red cells occurs. The serologic evaluation by the blood bank usually shows an antibody that reacts with a wide range of test cells and fails to show specificity for a particular antigen. Steroids, immunosuppressive drugs and intravenous immunoglobulin are used for the clinical management of this situation, although they may give little benefit.
 * Transfusion-related acute lung injury (TRALI) is a potentially severe complication that is usually caused by
 * Transfusion-induced GvHD (TI-GvHD) is caused by viable lymphocytes in units of transfused red cell. It is a rare but often fatal complication of transfusion. Immunosuppressed patients are at particular risk, but TI-GVHD may also occur in immunocompetent recipients of red cells from a haploidentical donor such as a family member. TI-GVHD usually occurs within 1–4 weeks of transfusion and is characterized by fever, rash, liver dysfunction, diarrhea and pancytopenia due to bone marrow failure. To reduce the risk of TI-GVHD, donated blood from a family member should be avoided or if used should always be irradiated before transfusion. Leukodepletion alone is inadequate for the prevention of this complication.
 * Transfusion-associated circulatory overload may occur in the presence of recognized or unrecognized cardiac dysfunction, or when the rate of transfusion is inappropriately fast. Signs and symptoms include dyspnea and tachycardia, and the chest radiograph shows the classic findings of pulmonary edema. Treatment focuses on volume reduction and cardiac support, as required.
 * Transmission of infectious agents including viruses, bacteria and parasites, are a major risk in blood transfusion. Even in countries where residual risk of transmission through blood of clinically significant pathogens (HIV, HBV, HCV and syphilis) has been reduced to minimal levels, problems continue to exist or emerge because:
 * A limited range of known pathogens is targeted in mandatory donor screening (excludes HPV B-19, HCMV, EBV, HAV, Yersinia enterolitica, other parasites, e.g., malaria)
 * Transmission of viruses still occurs (window period, sensitivity threshold of tests)
 * The clinical significance of newly identified infectious agents (HGV, GBV-C, TTV, SEN-V, HSV6,7,8) is not yet completely clarified and donors are not screened for these agents
 * Newly emerging infectious agents (WNV, SARS, Avian Flu, prions) constitute serious threats
 * Absence of widely accepted tests for bacteria (endogenous and exogenous) and for parasitic protozoa associated, e.g., with Chaga's disease, toxoplasmosis and babesiosis.

In many regions of the developing world, where thalassaemia is most prevalent, continued transmission of hepatitis B, hepatitis C and HIV underscores the importance of promoting the quality of national blood transfusion services, including voluntary blood donations, careful donor selection and screening, and public health services’ provision of necessary immunisation.

Summary Recommendations

 * Careful donor selection and screening – voluntary, regular non-remunerated blood donation.
 * Confirm diagnosis of thalassemia major.
 * Before initiation of transfusion therapy, confirm laboratory and clinical criteria.
 * Before first transfusion, extended red cell antigen typing of patients at least for C, E and Kell.
 * At each transfusion, give ABO, Rh(D) compatible blood. Matching for C, E and Kell antigen is recommended.
 * Before each transfusion, full cross-match and screen for new antibodies.
 * Keep record of red cell antibodies, transfusion reactions and annual transfusion requirements for each patient.
 * Use leukoreduced packed red cells. Pre-storage filtration is recommended, but blood bank pre-transfusion or bedside filtrations are acceptable alternatives.
 * Washed red cells for patients who have severe allergic reactions.
 * Use red cells stored in CPD-A, as fresh as possible (less than one week old) and in additive solutions for less than 2 weeks.
 * Transfuse every 2–5 weeks, maintaining pre-transfusion Hb above 9–10.5 g/dl, but higher levels (11–12 g/dl) may be necessary for patients with heart complications.
 * Keep post-transfusion Hb not higher than 14–15 g/dl.