Immunophenotyping as a profiling tool in human leucocyte antigen incompatible renal transplantation.

Human leucocyte antigen incompatible (HLAi) transplantation represents a key strategy for improving access for sensitised patients to the preferable treatment, of transplantation, for end-stage renal failure (ESRF). This laboratory based observational research study aimed to investigate key populations of recipient lymphocytes present at various stages of the HLAi transplant procedure, and to assess the data obtained in combination with other pertinent laboratory and clinical information, in order to build up an immunological profile. Data was collected from blood samples provided by seven prospective and thirteen retrospective HLAi kidney transplant recipients, and nine normal control individuals. Flow cytometry was utilised to examine lymphocyte subsets, and to perform T and B cell immunophenotyping. HLA-specific antibody definition was carried out using a single antigen bead-based assay, employing Luminex technology. Longitudinal data for the prospective participants, and collective data on the retrospective cohort, was scrutinised for any trends or significant associations. The effects of preconditioning and immunosuppression received were evident in the lymphocyte subset results of both groups of patients. Pre-treatment results in the prospective cohort also confirmed a chronic renal failure effect of reduced cell counts. Both groups of participants showed increased populations of memory T cells following transplantation, suggesting reconstitution from within this compartment. A peak in HLA-DR expression on T cells, at six months posttransplantation, was noted in the prospective group. Conversely, memory B cells remained depressed in both cohorts, with the repopulating B cells demonstrating a transitional or mature B cell phenotype in the prospective participants. A possible link between increased populations of plasmablasts posttransplantation, and detected levels of HLA-specific antibodies was indicated. The results demonstrated some intriguing trends and patterns that are worthy of further investigation, and it is recommended that elements of this pilot study are extended into larger prospective studies. As this study highlights, there is still much knowledge to be gained and potential laboratory support that could be given, that may improve the delivery of HLAi transplant programmes and thereby access to the superior treatment of transplantation for sensitised patients.