Induction of alloantigen-specific anergy in XXXX peripheral blood mononuclear cells by alloantigen stimulation with co-stimulatory signal blockade.

@entity1 @entity6306 @entity5 @entity7938 @entity1503 @entity281 @entity1358 @entity2132 @entity1361
Allogeneic hematopoietic stem cell transplantation (AHSCT) offers the best chance of cure for many @entity1 with congenital and acquired @entity1503 . Unfortunately, transplantation of alloreactive donor T cells which recognize and damage healthy @entity1 tissues can result in @entity2132 ( @entity2132 ). One challenge to successful AHSCT is the prevention of @entity2132 without associated impairment of the beneficial effects of donor T cells, particularly immune reconstitution and prevention of relapse. @entity2132 can be prevented by non-specific depletion of donor T cells from stem cell grafts or by administration of pharmacological immunosuppression. Unfortunately these approaches increase @entity281 and disease relapse. An alternative strategy is to selectively deplete alloreactive donor T cells after allostimulation by recipient @entity1358 ( @entity1358 ) before transplant. Early clinical trials of these allodepletion strategies improved immune reconstitution after HLA-mismatched HSCT without excess @entity2132 . However, some allodepletion techniques require specialized recipient @entity1358 production and some approaches may have off-target effects including depletion of donor pathogen-specific T cells and CD4 T regulatory cells .One alternative approach is the inactivation of alloreactive donor T cells via induction of alloantigen-specific @entity6306 . This is achieved by stimulating donor cells with recipient @entity1358 while providing blockade of @entity1361 -mediated co-stimulation signals.This "alloanergization" approach reduces alloreactivity by 1-2 logs while preserving pathogen- and @entity5 -associated antigen T cell responses in vitro. The strategy has been successfully employed in 2 completed and 1 ongoing clinical pilot studies in which alloanergized donor T cells were infused during or after HLA-mismatched HSCT resulting in rapid immune reconstitution, few @entity281 and less severe acute and chronic @entity2132 than historical control recipients of unmanipulated HLA-mismatched transplantation. Here we describe our current protocol for the generation of peripheral blood mononuclear cells (PBMC) which have been alloanergized to HLA-mismatched unrelated stimulator PBMC. Alloanergization is achieved by allostimulation in the presence of monoclonal antibodies to the ligands @entity7938 to block @entity1361 -mediated costimulation. This technique does not require the production of specialized stimulator @entity1358 and is simple to perform, requiring only a single and relatively brief ex vivo incubation step. As such, the approach can be easily standardized for clinical use to generate donor T cells with reduced alloreactivity but retaining pathogen-specific immunity for adoptive transfer in the setting of AHSCT to improve immune reconstitution without excessive @entity2132 .
