Liu X, et al. - Researchers focused on the features of variations in T cell receptor (TCR) diversity as well as their clinical value in cases with systemic lupus erythematosus (SLE) (n=877), rheumatoid arthritis (RA)(n=206), and healthy controls (HC, n=439). Findings revealed that variable (V), joining (J) and V-J pairing differed significantly between the SLE or RA and HC groups, and these differences enabled perfectly accurate discrimination between the three groups. They identified 198 SLE-associated and 53 RA-associated TCRs. In SLE and RA, common characteristics and high similarity were displayed by disease-associated clones. Compared to RA, SLE showed higher TCR heterogeneity with several organ specific properties. Findings revealed the link between clonal expansion and the concentration of disease-associated clones with disease severity. Both diseases were enriched with pathogen-related TCRs. Potential of these features of the TCR repertoire, especially the disease-associated clones, to serve as biomarkers was suggested in this study.