Objective Low-dose interleukin 2 (IL-2) administration has been shown to selectively modulate regulatory T (Treg) cell abundance and alleviate the progression of systemic lupus erythematosus (SLE). IL-2 level could be indicator of low-dose IL-2 usage in SLE patients. However, current methods for IL-2 detection are generally not sensitive to be used in clinic. This study aims to establish flow cytometry-based IL-2 detection as a feasible approach in determining IL-2 in peripheral blood of SLE patients. Methods Flow cytometry was used to quantify the relative mean fluorescence intensity (MFI) of IL-2 in CD3+T cells and other lymphocyte subsets in peripheral blood mononuclear cell (PBMCs) from a cohort of 134 SLE patients and 112 healthy controls (HC). Correlations between IL-2 MFI and clinical or laboratory parameters in SLE patients were also investigated. Results MFI of IL-2 represented IL-2 expression in CD3+T cells. IL-2 MFI was significantly lower in SLE patients compared to the HC group and negatively associated with anti-ribosomal protein antibodies, erythrocyte sedimentation rate (ESR), and blood urea. Conversely, it was positively correlated with IgA and hemoglobin. These associations with IgA, hemoglobin, ESR, and blood urea remained significant after adjusting for age and disease duration. IL-2 level was also positively correlated with the relative abundance of Th1, Th2, and Th17 cells. Furthermore, MFI of IL-2 recovered with effective treatment in SLE patients. Conclusions MFI of IL-2 serves as a feasible marker of IL-2, which is significantly decreased in SLE patients and recovered with treatment, suggesting its potential for assessing short-term disease status and treatment response in SLE patients.<Table Float="No" ID="Taba"> <tgroup cols="2"> <colspec align="left" colname="c1" colnum="1" /> <colspec align="left" colname="c2" colnum="2" /> <tbody> <row> <entry nameend="c2" namest="c1"> Key Points • IL-2 MFI can be used to estimate IL-2 expression level in SLE patients.  • IL-2 MFI is significantly reduced in SLE patients. • IL-2 MFI can serve as a marker for monitoring SLE activity and short-term status. </entry> </row> </tbody> </tgroup> </Table>

IL-2 detected by flow cytometry and its significance in systemic lupus erythematosus

期刊论文
发表日期：

2025年5月22日

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Yingni Li,
Tingting Wang,
Yuzhou Gan,
Xia Zhang,
Leixi Xue,
Boyi Xu,
Xiaolin Sun,
Zhanguo Li

摘要

Objective

Low-dose interleukin 2 (IL-2) administration has been shown to selectively modulate regulatory T (Treg) cell abundance and alleviate the progression of systemic lupus erythematosus (SLE). IL-2 level could be indicator of low-dose IL-2 usage in SLE patients. However, current methods for IL-2 detection are generally not sensitive to be used in clinic. This study aims to establish flow cytometry-based IL-2 detection as a feasible approach in determining IL-2 in peripheral blood of SLE patients.

Methods

Flow cytometry was used to quantify the relative mean fluorescence intensity (MFI) of IL-2 in CD3⁺T cells and other lymphocyte subsets in peripheral blood mononuclear cell (PBMCs) from a cohort of 134 SLE patients and 112 healthy controls (HC). Correlations between IL-2 MFI and clinical or laboratory parameters in SLE patients were also investigated.

Results

MFI of IL-2 represented IL-2 expression in CD3⁺T cells. IL-2 MFI was significantly lower in SLE patients compared to the HC group and negatively associated with anti-ribosomal protein antibodies, erythrocyte sedimentation rate (ESR), and blood urea. Conversely, it was positively correlated with IgA and hemoglobin. These associations with IgA, hemoglobin, ESR, and blood urea remained significant after adjusting for age and disease duration. IL-2 level was also positively correlated with the relative abundance of Th1, Th2, and Th17 cells. Furthermore, MFI of IL-2 recovered with effective treatment in SLE patients.

Conclusions

MFI of IL-2 serves as a feasible marker of IL-2, which is significantly decreased in SLE patients and recovered with treatment, suggesting its potential for assessing short-term disease status and treatment response in SLE patients.

Key Points

• IL-2 MFI can be used to estimate IL-2 expression level in SLE patients.

• IL-2 MFI is significantly reduced in SLE patients.

• IL-2 MFI can serve as a marker for monitoring SLE activity and short-term status.