Elevated <scp>CD39</scp> ⁺ T Cells Contribute to Immune Regulatory Imbalance in Systemic Lupus Erythematosus

This study aims to explore the role of CD39 in peripheral blood T cells and its alterations in patients with systemic lupus erythematosus (SLE), focusing on its potential for clinical diagnosis. Peripheral blood samples were collected from 58 newly diagnosed untreated SLE patients and 48 healthy controls. Flow cytometry was used to evaluate CD39 expression in CD4⁺ T cell subsets (TEMRA, N, EM, CM) and Treg/non-Treg populations. The expression of CD39 and related molecules (VNN2, CD226, CD62L, TIM3, HLA, GZMB) was analysed in peripheral blood mononuclear cells (PBMCs). The correlation between CD39⁺ T cell subsets and clinical markers was assessed, and the diagnostic value of CD39⁺ subsets was evaluated using receiver operating characteristic (ROC) curve analysis. CD39 expression was significantly elevated in CD4⁺ T cells, especially in TEMRA and non-Treg subsets. CD39⁺ T cells exhibited higher levels of effector molecules such as TIM3, CD226, HLA, VNN2 and GZMB, while CD62L expression was lower. The proportion of CD39 related T cells in SLE patients was significantly higher compared to healthy controls, with significant correlations to clinical markers like anti-SSB antibodies and complement C4. ROC analysis revealed that CD39⁺ T cell subsets, particularly in N and non-Treg cells, showed potential for diagnosing SLE. CD39⁺ T cells are involved in immune dysregulation in SLE, and their increased presence and subset distribution suggest their potential as diagnostic markers for SLE.