Background: T cells play a pivotal role in primary Sjogren’s syndrome (pSS), necessitating a comprehensive understanding for targeted therapies. While KLRB1 is associated with autoimmune diseases, its role in pSS T cells is still unclear.

Objectives: The objective of this study was to explore the function of KLRB1 in human CD4+ T cells and uncover its relevance in pSS.

Methods: This study collected peripheral blood samples from 37 healthy controls and 44 pSS patients, using RNA-Seq data from pSS patient PBMCs to analyze KLRB1 expression in T cells. Flow cytometry was utilized to determine KLRB1-expressing T lymphocyte subsets in pSS patients and healthy controls. CD25, Ki-67, cytokine secretion, and chemokine receptor expression were compared between CD4+KLRB1+ and CD4+KLRB1- T cells, with correlation analysis conducted between KLRB1-related T cell subsets and clinical indicators. ROC curves were employed to explore KLRB1’s diagnostic potential for pSS.

Results: Upon T cell activation, KLRB1 expression is notably increased, accompanied by significantly elevated levels of Ki-67 and CD25 in CD4+KLRB1+ T cells in comparison to CD4+KLRB1- T cells. Furthermore, CD4+KLRB1+ T cells exhibit heightened secretion of pro-inflammatory cytokines including IL-17A, IL-21, IL-22, and IFN-γ upon stimulation. Additionally, there is a significantly higher presence of CCR5+, CCR2+, CX3CR1+, CCR6+, and CXCR3+ cells within CD4+KLRB1+ T cells as opposed to CD4+KLRB1- T cells. Importantly, KLRB1 expression in CD4+ T cells is significantly elevated in pSS patients compared to healthy controls (HCs), and this upregulation of KLRB1 correlates significantly with clinical disease indicators in pSS patients.

Conclusion: KLRB1 serves as a distinctive marker of CD4+ T cell activation phenotype, and its heightened expression within CD4+ T cells of pSS patients implies its potential role in pSS pathogenesis and its potential as a supplementary diagnostic indicator for pSS.

REFERENCES: NIL.

Acknowledgements: This research was supported by grants from National Natural Science Foundation of China (82271755, 31972899, 81871230).

Disclosure of Interests: None declared.