Double-filtered leukoreduction as a method for risk reduction of transfusion-associated graft-versus-host disease

Abstract

Background Transfusion-associated graft-versus-host disease (TA-GvHD) is caused by leukocytes, specifically T cells within a transfused blood product. Currently, the prevention of transfusionassociated graft-versus-host disease is performed by irradiation of blood products. With a sufficient reduction of leukocytes, the risk for TA-GvHD can be decreased. With consistent advances in current state-of-the-art blood filters, we herein propose that double filtration can sufficiently reduce leukocytes to reduce the risk for TA-GvHD. Materials Thirty RBC concentrates were filtered with leukocyte filters, followed by storage at 1-6 o C for 72 hours, and then a second filtration was performed. Residual leukocytes in the doublefiltered RBC units (n = 30) were assessed with flow cytometric methods, and an additional assay with isolated peripheral blood mononuclear cells (PBMCs) (n = 6) was done by both flow cytometric methods and an automated hematology analyzer. Quality of the RBCs after filtration was evaluated by hematological and biochemical tests. In vitro T cell expansion was performed using anti-CD3/CD28-coated Dynabeads or anti-CD3 (OKT3). In vivo experiment for GvHD was performed by using NOD.Cg-Prkdc scid Il2rg tm1Wjl /SzJ (NSG) mice. Results Double-filtered blood products showed residual leukocyte levels below detection limits, which calculated to be below 1200-2500 cells per blood unit. In vitro expansion rate of T cells showed that 6x10 3 and 1x10 3 cell-seeded specimens showed 60.8±10.6 fold and 10.2 ±9.7-fold expansion, respectively. Cell expansion was not sufficiently observed in wells

Hypothermic storage of leukoreduced red blood cells for greater than 21 days is a safe alternative to irradiation

“…To ensure that the irradiated inventory is suitable for as many patients as possible, O-units are often selected for the "irradiated stock" placing further pressure on the limited supply of O-units. Thus, alternative "GVHD-safe" products that do not require a separate inventory management nor an on-site irradiator, such as photochemical inactivation of lymphocytes, [35][36][37] X-ray irradiation, 38 pathogen or double-filtered leukoreduction methods, 39,40 and others should be considered. However, all these methods have various adverse biochemical or biophysical effects on the cells and, therefore, may affect RBC quality.…”

Insights into mechanisms of graft-versus-host disease through humanised mouse models

“…Cell subset manipulation or transfer experiments in humanised mice have provided understanding of the mechanisms of GVHD development by examining the role of specific effector T cell subsets and the role of regulatory subsets including Tregs, MDSCs, tolerogenic DCs and mesenchymal stem cells (MSCs) (as summarised below and in Table 2, 3 and 4). CD4 + and CD8 + T cell subsets readily engraft in immune deficient mice (73)(74)(75)(82)(83)(84)(85)(86)(87)(88)(89), with an increased ratio of human CD4 + :CD8 + T cells indicative of GVHD severity (90), reflecting observations in allogeneic HSCT recipients (91,92). Injection of isolated human T cell subsets into NOG mice has revealed both CD4 + and CD8 + T cells alone can mediate GVHD (93).…”

Preventing transfusion‐associated graft‐versus‐host disease with blood component irradiation: indispensable guidance for a deadly disorder

“…Filtering to decrease the number of leucocytes mitigate the risk of TA-GvHD may be one approach. An intriguing study by Chun et al 17 demonstrated a reduction in the residual leucocyte count in the product, although not sufficient to confirm a reduction in TA-GvHD and came at the expense of approximately 20% of the red cell content.…”