Flow Cytometry in Transplantation

Human leukocyte antigen (HLA) molecules play a great role in tissue compatibility and transplantation. Preformed donor-specific antibodies to human leukocyte antigen (HLA) molecules have been shown to be a contraindication in both solid organ and hematopoietic stem cell transplantation (HSCT). The preformed anti-HLA antibodies are associated with the acute antibody-mediated rejection (AMR) and increased risk of graft loss. A flow cytometry crossmatch assay (FCXM) helps in identifying any antibodies present in recipient that can bind to its cognate antigen on the donor cell. The solid phase bead-based assays are very sensitive as the fluorescence detection is performed by cytometer. Currently, many variants of the HLA bead-based assays are available commercially with the ability of detection and identification of specificities of the HLA and non-HLA antibodies. This solid phase assay uses a pool of polystyrene beads coated which are labeled with a different proportion of two dyes that provide each bead a unique dye signature.