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Rabbit antithymocyte globulin (rATG; thymoglobulin, Genzyme) in combination with cyclosporine, as first-line immunosuppressive therapy, was evaluated prospectively in a multicenter, European, phase 2 pilot study, in 35 patients with aplastic anemia. Results were compared with 105 age-and disease severitymatched patients from the European Blood and Marrow Transplant registry, treated with horse ATG (hATG; lymphoglobulin) and cyclosporine. The primary end point was response at 6 months. At 3 months, no patients had achieved a complete response to rATG. Partial response occurred in 11 (34%). At 6 months, complete response rate was 3% and partial response rate 37%. There were 10 deaths after rATG (28.5%) and 1 after subsequent HSCT. Infections were the main cause of death in 9 of 10 patients. The best response rate was 60% for rATG and 67% for hATG. For rATG, overall survival at 2 years was 68%, compared with 86% for hATG (P ‫؍‬ .009). Transplant-free survival was 52% for rATG and 76% for hATG (P ‫؍‬ .002). On multivariate analysis, rATG (hazard ratio ‫؍‬ 3.9, P ‫؍‬ .003) and age more than 37 years (hazard ratio ‫؍‬ 4.7, P ‫؍‬ .0008) were independent adverse risk factors for survival. This study was registered at www.clinicaltrials.gov as NCT00471848. (Blood. 2012;119(23): 5391-5396) IntroductionHistorically, horse antithymocyte globulin (hATG) has been the preferred animal source of ATG as first-line treatment for acquired aplastic anemia (AA) patients who are ineligible for hematopoietic stem cell transplantation (HSCT). For severe AA (SAA), the combination of ATG and cyclosporine (CSA) results in a response rate of 60% to 75% of patients, and the response is superior to using either agent alone. [1][2][3][4][5] The addition of G-CSF to the combination of ATG and CSA has shown no significant benefit either in terms of response or survival, 6-8 although it may reduce infectious complications and duration of hospital admission. 6 For patients with nonsevere AA (NSAA) who are transfusion dependent, the combination of ATG and CSA is superior to CSA alone, with a higher response rate, higher blood counts, and improved disease-free survival. 9 Rabbit ATG (rATG) is more commonly used for a second course after relapse or lack of response to a first course of hATG. Response to a second course for nonresponse to a first course varies from 30% to 77% 10,11 and only 11% in children. 12 In contrast, in patients relapsing after a first course, the response to a second course is 65%. 11,13 Until 2007, there were 2 preparations of hATG, namely, lymphoglobulin (Genzyme) and ATGAM (Pfizer). The most commonly used preparation of rATG (thymoglobulin, Genzyme) uses the same immunogen as lymophoglobulin; horses or rabbits are immunized with human thymocytes obtained at the time of cardiac surgery from newborn infants. rATG is more immunosuppressive than hATG; it results in more prolonged lymphopenia, 14 and it is more effective at preventing and treating acute renal allograft rejection. 15 We undertook a European study conducted by th...

This guideline was compiled according to the British Society for Haematology (BSH) process at https://b-s-h.org.uk/med ia/16732/bsh-guidance-development-process-dec-5-18.pdf. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) nomenclature was used to evaluate levels of evidence and to assess the strength of recommendations. The GRADE criteria can be found at http:// www.gradeworkinggroup.org. Literature review details The last guideline covering this topic was published in 2012. Publications were searched systematically in English between 2008 and August 2019 covering the period since the last publication (Appendices 2 and 3). Review of the manuscript Review of the manuscript was performed by the BSH Guidelines Committee Transfusion Task Force, the BSH Guidelines Committee and the Transfusion and Malignant Haematology sounding board of BSH, and relevant specialists including paediatric cardiac anaesthetists and haematologists specialising in malignant diseases. It was also on the members section of the BSH website for comment. Purpose To provide healthcare professionals with clear guidance on situations when the use of irradiated blood components is indicated. The term 'blood component' means the therapeutic constituents of human blood (red cells, white cells, platelets and plasma) that can be prepared by various methods (JPAC https://www.transfusionguidelines.org/red-book/defini tions). The multidisciplinary writing group developed evidence-based clarification and practical guidance in clinical areas of ambiguity. Publications relating to patients of all age groups have been assessed. The guidance may not be appropriate in all patient situations and assessment of individual circumstances with the appropriate risk assessments and patient involvement may lead to alternative decisions.