Background: Clinical studies suggest that the dysfunction of T cells and B cells may play an essential role in the pathogenesis of idiopathic nephrotic syndrome (INS), but laboratory evidence is lacking. Therefore, this study explored T-cell receptor (TCR) and B-cell receptor (BCR) profiling in children with idiopathic nephrotic syndrome.

Methods: High-throughput sequencing technology was used to profile the TCR and BCR repertoires in children with INS. Peripheral blood was collected from ten INS patients, including five vinculin autoantibody-positive patients and five vinculin autoantibody-negative patients, before and after treatment. TCR and BCR libraries were constructed by 5′-RACE and sequenced by a DNBSEQ-T7 sequencer, and sequence analyses were performed using ReSeqTools, FastP, MiXCR, and VDJtools.

Results: The TRA (T-cell receptor α), TRG (T-cell receptor γ), and IGH (immunoglobulin heavy chain) repertoires of the INS group were occupied by highly abundant clonotypes, whereas small clonotypes occupied the healthy group, especially TRA. A significant increase in the Shannon–Weaver index was observed for the TRA and TRG repertoires after treatment in vinculin autoantibody-negative patients, but a significant increase in the IGH repertoire after treatment was observed in vinculin autoantibody-positive patients. The frequency of some V–J pairs was significantly enriched in steroid-sensitive nephrotic syndrome patients. The usage frequency of the V and J genes was skewed in patients, which seemed not related to immunosuppressive therapy. However, after effective treatment, dynamic changes in the size of the individual clonotype were observed.