Determination of an unrelated donor pool size for human leukocyte antigen-matched platelets in Brazil

Abstract

BackgroundSuccessful transfusion of platelet refractory patients is a challenge. Many potential donors are needed to sustain human leukocyte antigen matched-platelet transfusion programs because of the different types of antigens and the constant needs of these patients. For a highly mixed population such as the Brazilian population, the pool size required to provide adequate platelet support is unknown.MethodsA mathematical model was created to estimate the appropriate size of an unrelated donor pool to provide human leukocyte antigen-compatible platelet support for a Brazilian population. A group of 154 hematologic human leukocyte antigen-typed patients was used as the potential patient population and a database of 65,500 human leukocyte antigen-typed bone marrow registered donors was used as the donor population. Platelet compatibility was based on the grading system of Duquesnoy.ResultsUsing the mathematical model, a pool containing 31,940, 1710 and 321 donors would be necessary to match more than 80% of the patients with at least five completely compatible (no cross-reactive group), partial compatible (one cross-reactive group) or less compatible (two cross-reactive group) donors, respectively.ConclusionThe phenotypic diversity of the Brazilian population has probably made it more difficulty to find completely compatible donors. However, this heterogeneity seems to have facilitated finding donors when cross-reactive groups are accepted as proposed by the grading system of Duquesnoy. The results of this study may help to establish unrelated human leukocyte antigen-compatible platelet transfusions, a procedure not routinely performed in most Brazilian transfusion services.

A real‐life evaluation of two platelet cross‐matching programmes for the treatment of patients refractory to platelet transfusions

“…In 1999, we introduced the routine use of a platelet XM programme because of the small size of our HLA‐typed donor panel and, in 2004, reported satisfactory results in 40 alloimmunized refractory patients . Although our positive results were confirmed by other investigators , the findings of studies indicating less satisfactory outcomes prompted us to make this critical retrospective evaluation of the effectiveness of our programme.…”

“…This article describes the findings of a critical review of the platelet XM programmes implemented by two Italian hospitals using a commercially available solid-phase antibody assay to select compatible platelets for haematological patients with alloimmune refractoriness to random donor platelets. The study was triggered by a recent investigation reporting the very limited efficacy of platelet XM and HLA selection [19], which conflicted with the findings of a number of positive studies, including one previously published by our group [6][7][8][9][10][11][12][13][14][15][16][17][18].…”

“…A commercially available solid-phase antibody detection system was used for platelet antibody detection and XM. Forty-nine alloimmune refractory patients at PHM and 13 at SCB, respectively, received a median [IQR] of 12 [6][7][8][9][10][11][12][13] and 18 [13-15] XM compatible platelet transfusions after the detection of refractoriness. The absolute increases in post-transfusion platelet counts obtained using random, and XM platelets were retrieved from the patients' hospital records.…”

“…Alloimmunized refractory patients are a significant challenge for blood transfusion services as they are exposed to an increased risk of bleeding in the absence of prompt and effective platelet transfusion. Strategies for overcoming alloimmune refractoriness are based on the use of compatible platelets selected from large panels of HLA‐typed donors or cross‐matching (XM) , which have been found to be similarly effective .…”

“…Alloimmunized refractory patients are a significant challenge for blood transfusion services as they are Correspondence: Nicoletta Revelli, DSc, Department of Transfusion Medicine and Hematology, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, via Francesco Sforza, 35, 20122 -Milano, Italy E-mail: nicoletta.revelli@policlinico.mi.it exposed to an increased risk of bleeding in the absence of prompt and effective platelet transfusion. Strategies for overcoming alloimmune refractoriness are based on the use of compatible platelets selected from large panels of HLA-typed donors or cross-matching (XM) [6][7][8][9][10][11][12][13][14][15][16][17], which have been found to be similarly effective [9].…”