AUSTRALIAN & NEW ZEALAND SOCIETY OF BLOOD TRANSFUSION INC. AUSTRALIAN RED CROSS BLOOD SERVICE NEW ZEALAND BLOOD SERVICE Guidelines for Gamma Irradiation of Blood Components Revised 2003 AN ZS B T Australian & New Zealand Society of Blood Transfusion Inc
Copyright by The Australian & New Zealand Society of Blood Transfusion Inc. Australian Red Cross Blood Service New Zealand Blood Service Apart from any fair dealing for the use of private study, research, criticism, or review as permitted under the Copyright Act, no part of this book may be transmitted or reproduced in any form, electronic or mechanical, or by any information storage and retrieval system, without the written permission of the Publishers. Published in Australia by: Australian & New Zealand Society of Blood Transfusion Inc. 145 Macquarie Street Sydney NSW 2000 AUSTRALIA ISBN No: 0 9577262 4 4 1 st ASBT Edition 1996
Australian & New Zealand Society of Blood Transfusion Australian Red Cross Blood Service New Zealand Blood Service Guidelines for Gamma Irradiation of Blood Components RATIONALE Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare, but usually fatal, complication of transfusion. The risk associated with an individual transfusion depends on the number and viability of contaminating lymphocytes, the susceptibility of the patient's immune system to their engraftment and the degree of immunological disparity between donor and patient. The mainstay of prevention is gamma irradiation, which inactivates T lymphocytes whilst preserving the function of other blood cells. Leucodepletion by current filtration technology is inadequate [unproven] for this purpose. SCOPE These guidelines cover the procedural aspects, equipment dosimetry and maintenance, and clinical indications for gamma-irradiated blood components. 1. PROCEDURAL ASPECTS 1.1 Dose of gamma radiation Experience has revealed the importance of the selection of an effective dose of gamma radiation. The minimum dose achieved in the irradiation field should be 25 Gy, with no part receiving greater than 50 Gy. 1.2 Effect of irradiation on blood components Red cells / Whole Blood There is evidence that gamma irradiation results in reduced post-transfusion red cell recovery, but only after prolonged storage. Irradiation has no clinically significant effect on red cell ph, glucose consumption, ATP and 2,3 DPG levels. However gamma irradiation of red cells does increase the rate of efflux of intracellular potassium. In considering the clinical significance of this, both the speed and volume of the transfusion, as well as the age of the blood, must be taken into account. Platelets Gamma irradiation below 50 Gy has not been shown to produce significant clinical changes in platelet function. Granulocytes The evidence for irradiation damage to granulocyte function is conflicting, but in any case granulocyte products must be transfused as soon as possible after preparation.
1.3 Blood component shelf life Red cells Red cells may be irradiated at any time up to 14 days after collection, and thereafter stored for a further 14 days from irradiation. Where the patient is at particular risk from hyperkalaemia, it is recommended that red cells be transfused within 24 hours of irradiation. [Red cells can re-enter the inventory as long as the altered shelf is observed]. Platelets Platelets can be irradiated at any stage in their five-day storage and can thereafter be stored up to their normal shelf life of five days after collection. Granulocytes Granulocytes for all recipients must be irradiated as soon as possible after production, and thereafter transfused with minimal delay. 1.4 Labelling and documentation requirements All irradiated components must be identified [and labelled immediately] with an approved label. The label should be permanent and include the date and dose of irradiation and any reduction in shelf life. Each batch of one or more units should be monitored using a radiation-sensitive label or device to indicate adequate exposure to gamma rays. As a minimum, a label should be included with every batch. However, it is not necessary to attach a label to every pack in a batch provided that the irradiation procedure follows a validated, documented and well-controlled system of work practice. There must be a permanent record of all units irradiated. 2. EQUIPMENT DOSIMETRY AND MAINTENANCE 2.1 Choice of blood irradiators Irradiation of blood components will normally be undertaken using dedicated Blood irradiators. Such instruments will contain a long half-life, gamma-emitting source. The source must be double encapsulated. All specifications should be available. Adequate shielding must be provided to ensure that all dose rates are as low as is reasonably achievable at all accessible points. Radiation safety, dosimetry and personnel safety issues should be under the responsibility of a suitability qualified person in accordance with legislation. In some circumstances linear accelerators or similar equipment may be used to irradiate blood components. These guidelines are applicable to such situations and systems should be put in place to ensure that dosimetry requirements contained within these guidelines are met. 2.2 Commissioning The manufacturer, or their agent, should commission the irradiator and provide a calibration certificate for a dose rate at a specified point in the canister. 2.3 Dosimetry and Operation Following calibration/recalibration, a table must be produced which gives irradiation times for specified doses for a set period. Both the dose rate and the dose distribution must be checked upon installation, at least annually, and after any source change or mechanical alterations, particular to the rotating turntable.
2.4 Quality control of procedures All operators must have been adequately trained in the use of the equipment. 2.5 Maintenance Wipe tests must be carried out at regular intervals, preferably six monthly, to check for leakage of radioactive contamination. 2.6 Legislation Ensure compliance with local legislation. 3. CLINICAL INDICATIONS FOR GAMMA IRRADIATED BLOOD COMPONENTS These Guidelines outline the minimum clinical criteria for the use of irradiated blood components based on currently available evidence. It is recognised that individual centres may utilise wider criteria. This is acceptable if the criteria are clearly documented and in all instances meet or exceed the requirements identified below. Blood components that must be gamma irradiated Lymphocyte viability is retained in stored red cells for at least three weeks, and TA-GVHD has developed following transfusion of whole blood, red cells, platelet and granulocytes. For at-risk patients, all red cell, platelet and granulocyte transfusions must be irradiated, except cryopreserved red cells after deglycerolization. It is not necessary to irradiate fresh frozen plasma, cryoprecipitate or fractionated plasma products. Blood stem cells for the purposes of transplantation must not be irradiated. 3.1 Donations from family members and HLA-selected donors Because of the possibility of shared HLA haplotypes within families, donations from family members pose a particular risk of TA-GVHD, especially when the recipient is a neonate. All transfusions from blood relatives must be irradiated, even if the patient is immunocompetent. Likewise, all HLA-selected platelets must be irradiated, even if the patient is immunocompetent. 3.2 Paediatric practice The newborn may be at particular risk of TA-GVHD either because of possible physiological immune incompetence or because of an underlying congenital T-cell immunodeficiency. The majority of cases of TA-GVHD reported in apparently immune competent infants have occurred in the setting of intrauterine transfusion followed by exchange transfusion. Intrauterine and exchange transfusion All blood for intrauterine transfusion must be irradiated. It is essential to irradiate blood for exchange transfusion if there has been a previous intrauterine transfusion, or if the donation comes from a relative. For other exchange transfusion cases, irradiation is recommended provided this does not unduly delay transfusion. Blood less than 5 days of age should be used for intrauterine and exchange transfusion, and must be transfused within 24 hours of irradiation. Top-up transfusion There is no necessity to irradiate blood for routine top-up transfusions of premature or term infants unless either there has been a previous intrauterine transfusion or the blood has come from a blood relative, in which case the blood must be irradiated.
Platelet transfusions Irradiation must be performed on platelets transfused in utero to treat alloimmune thrombocytopenia, and on platelet transfusions given after birth to infants who have received either red cells or platelets in utero. However, there is no requirement to irradiate platelets for pre-term or term infants, unless they are derived from blood relatives. Granulocyte transfusions As stated previously all granulocyte transfusions must be irradiated for babies of any age and transfused as soon as possible after irradiation. Congenital immunodeficiencies in infants and children Irradiation of cellular blood products is recommended for all infants/children with suspected or diagnosed T-cell immune deficiency states. Acquired immunodeficiency states in childhood There is no indication for the irradiation of cellular blood components for children who are HIV antibody positive, or who have AIDS. 3.3 Acute leukaemia and bone marrow / blood stem cell transplantation Acute leukaemia It is not necessary to irradiate red cells or platelets for adults or children with acute leukaemia, except for HLA-matched platelets or donations from blood relatives. Allogeneic bone marrow / peripheral blood stem cell transplantation All recipients of allogeneic bone marrow / peripheral blood stem cell transplants must receive gamma-irradiated blood products from the time of initiation of conditioning chemo/radiotherapy. This should be continued while the patient remains on GVHD prophylaxis, usually for a minimum of six months or until lymphocytes are >1 X 10 9 /L. Autologous bone marrow /peripheral blood stem cell recipients Patients undergoing bone marrow or peripheral blood stem cell harvesting for future autologous reinfusion should only receive gamma irradiated allogeneic cellular blood products during and for seven days before the bone marrow/stem cell harvest to prevent the collection of viable allogeneic T lymphocytes. All patients undergoing bone marrow transplantation must then receive gamma irradiated cellular blood products from the initiation of conditioning chemo/radiotherapy until at least three months post autograft. [or six months if Total Body Irradiation used]. 4. OTHER PATIENT GROUPS Other indications for gamma irradiated blood products include Hodgkin's disease and patients on purine analogue drugs [such as fludarabine, cladribine]. There is currently no data to support a stated period of time to use irradiated products for patients following treatment with purine analogues.
5. TABULATED INDICATIONS CLINICAL INDICATIONS FOR IRRADIATED CELLULAR PRODUCTS A Definite indications These are indications where there is strong evidence to support the requirement for use of irradiated blood components or where there is clear consensus on the requirement within published guidelines Allogeneic and Autologous Bone Marrow/PBSC Transplant recipients Congenital Cellular Immunodeficiency Disorders Intrauterine and all subsequent transfusion and neonatal exchange transfusions Aplastic anaemia patients receiving immunosuppressive therapy Hodgkin's Disease Patients receiving purine analogues with associated immunosuppression Dedicated [directed] donations (from blood relatives) HLA matched single donor platelets Granulocyte transfusions B Possible indications This includes settings where case reports have been published but where no controlled studies are available. Irradiation is not required in published international guidelines. T Cell malignancies Patients with B cell malignancy who receive chemotherapy and/or radiotherapy leading to lymphopenia <0.5 x 10 9 /L Therapeutic antibodies against T cells Acute Leukaemia Chronic Myeloid Leukaemia Any patient who receives high doses of chemotherapy and/or irradiation sufficient to cause lymphopenia <0.5 x 10 9 /L Patients receiving long term or high dose steroids as therapy for their malignancies Premature infants weighing less than 1200g C No indication No cases have been reported AIDS (where none of the above apply) Congenital humoral deficiency disorder Term infants (where none of the above apply) Thalassaemias Haemophilia
REFERENCES These guidelines are based on and are consistent with the references cited below: 1. Guidelines on gamma irradiation of blood components for the prevention of transfusionassociated graft-vs-host disease prepared by British Committee for Standards in Haematology. Transfusion Medicine 1996; 6:261-271. 2. Guidelines for irradiated blood products. Australasian Society of Blood Transfusion, 1996. 3. Transfusion-Associated Graft-Versus-Host Disease [Review]. British Journal of Haematology, 2002,117, 275-287. Disclaimer Institutions using these guidelines need to formulate their own policies according to their patient population and availability of irradiated products. By necessity these policies may need to be much broader to cover all possible eventualities.