Identification of expanded T-cell clones by spectratyping in nonfunctioning kidney transplants

Maria Cappuccilli,1 Gabriele Donati,1 Giorgia Comai,1 Olga Baraldi,1 Diletta Conte,1 Irene Capelli,1 Valeria Aiello,1 Andrea Pession,2 Gaetano La Manna1 1Department of Experimental Diagnostic and Specialty Medicine (DIMES), Nephrology, Dialysis, and Renal Transplant Unit, 2Molecular Laboratory of Pediatrics, Hematology–Oncology Unit, St Orsola Hospital, University of Bologna, Bologna, Italy Background: The aim of this study was the application of complementarity-determining region-3 spectratyping analysis to determine T-cell-repertoire complexity and to detect T-cell-clone expansion, as a measure of immune response in nonfunctioning kidney transplants (group hemodialysis-transplant [HD-Tx]), nontransplanted dialysis patients (group hemodialysis [HD]), and normal subjects as controls (group C).Patients and methods: Analysis of T-cell receptor (TCR) diversity by spectratyping was applied to peripheral blood samples collected from 21 subjects: eight in group HD-Tx, seven in group HD, and six in group C.Results: Considering the extent of the skew in TCR variable region repertoires as a measure of clonal T cells, we found that the number of altered spectra showed a progressive increase from normal subjects to dialysis patients and to nonfunctioning kidney transplants, respectively. Healthy subjects had the lowest number of altered spectra, and patients with nonfunctioning kidney transplants the highest. Differences were significant for group HD-Tx vs group C (P=0.017) and group HD vs group C (P=0.015), but not between nonfunctioning kidney-transplant recipients and dialysis patients (group HD-Tx vs group HD).Conclusion: Although dialysis appears to be a weaker trigger for clonal expansion of T cells, our data suggest that the utilization of complementarity-determining region-3 spectratyping analysis of the TCR repertoire might be useful to monitor specific immunoactivation in patients before and after kidney transplantation. Keywords: dialysis, nonfunctioning kidney transplant, T-cell repertoire, TCR spectratyping&nbsp