High-throughput Treg cell receptor sequencing reveals differential immune repertoires in rheumatoid arthritis with kidney deficiency

Background: Regulatory T (Treg) cells are important immune cells that are regulated by adaptive immunity in the composition of Treg-cell subsets and T-cell receptors (TCRs). Treg cells are related to most autoimmune diseases, such as rheumatoid arthritis (RA). In traditional Chinese medicine (TCM), RA is typically attributed to kidney deficiency (KD) associated with the immunosenescence that causes immune dysfunction and the impaired function of Treg cells. So far, however, no mechanism related to KD and immune repertoires has been identified in RA. Methods: Flow cytometry and high-throughput Treg-cell receptor sequencing were used to investigate the amount of different Treg-cell subsets and the diversity of TCRs between RA patients and healthy subjects, as well as between KD RA and non-KD RA patients. RT-qPCR was used to validate the high-throughput sequencing results. Results: The data showed that the amount of naive Treg cells in KD patients was less than in non-KD RA patients (P = 0.004) with no significant differences observed between other subsets. In the TCR of Treg cells, the length of complementarity determining region 3 (CDR3) was low and clonotypes increased in the KD group compared with the non-KD group. The diversity and abundance of Treg TCRs were low, as determined by the Hill number. In addition, several V(D)J combinations, such as T-cell receptor beta variable 7-2 (TRBV7-2), TRBV11-1, TRBV13, TRBV15, and TRBJ2-3, varied significantly between the two groups, indicating that KD causes Treg dysfunction. RT-qPCR shows that FOXP3 expression in peripheral blood Treg is lower in KD than in non-KD. Conclusion: The results demonstrate the close correlation between KD and immune repertoires in RA and provide a new evaluation method for RA in TCM.