Blood T‐Cell Repertoire in Idiopathic Nephrotic Syndrome Recurrence Following Kidney Transplantation

Corticosteroid resistant idiopathic nephrotic syndrome (CR‐INS) is a glomerulopathy that recurs after kidney transplantation in 30–50% of patients, suggesting the involvement of systemic albuminuric factors, probably produced by activated T cells. We investigated peripheral T‐cell selection and expansion before and after transplantation to identify and characterize T‐lymphocyte patterns potentially associated with INS recurrence. We used a combined qualitative and quantitative assessment of Vβ mRNA alterations at the level of the complementary determining region 3‐length distribution (CDR3‐LD) of the T‐cell receptor (TCR). Peripheral blood mononuclear cells (PBMC) were collected from 18 CR‐INS patients (8 with recurrence and 10 without recurrence) on the day of transplantation as well as at 1 month, 1 year and 5 years after transplantation, and Vβ transcriptomes were analyzed. Our data show that blood T cells from patients with INS recurrence display a TCR repertoire that is stable in time and has a similar level of CDR3‐LD alterations as the T‐cell repertoire of control patients, both before and after transplantation. These results suggest that the process of INS recurrence does not involve TCR activation or specific clonal expansion of T cells. However, these results do not exclude a role for T cells in the production of an albuminuric factor. Although recurrence of idiopathic nephrotic syndrome has been ascribed to T cell activation, this study found no increase in T cell activation or specific clonal expansion associated with recurrence, compared to control patients.