Characteristics, dynamic changes, and prognostic significance of TCR repertoire profiling in patients with renal cell carcinoma.

The co-evolving tumour cells and the systemic immune environment are mutually dysregulated. Tumours affect the immune response in a complex manner. For example, although lymphocytes are mobilized in response to tumours, their function is impaired by tumour progression. This study aimed to explore how the baseline and dynamic renal cell carcinoma (RCC) tumour burdens affect the T-cell repertoire, and whether the baseline T-cell receptor ß-chain (TCRB) diversity predicts prognosis. To characterise the TCRB repertoire, the baseline and follow-up peripheral TCRB repertoires of 45 patients with RCC and 2 patients with benign renal disease patients were examined using high-throughput TCRB sequencing. To explain the significance of TCRB diversity, 56 peripheral leukocyte samples from 28 patients before and after surgery were subjected to transcriptome sequencing. To validate the results, an advanced RCC patient's sample was subjected to single-cell RNA sequencing (scRNA, 10x Genomics). Higher TCRB diversity was found to be correlated with a higher lymphocyte-to-neutrophil ratio, especially indicating more naïve T cells. High-baseline TCRB diversity predicted a better prognosis for stage IV patients, and different tumour burdens exerted distinct effects on the immune status. The pre-operative TCRB diversity was significantly higher in benign and stage I (low tumour burden) RCC patients than in stage IV (high tumour burden) patients. After the tumour burden of advanced patients was mostly relieved, we observed that the TCRB diversity was restored, T-cell exhaustion was reduced, and naïve T-cells were mobilized. It was demonstrated that the circulating TCRB repertoire could reflect the immune status and predict prognosis, and to some extent that cytoreductive nephrectomy (CN) reduces the burden of the immune system in advanced patients, which might provide a good opportunity for immunotherapy. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.