Integrated immune profiling identifies a coordinated T-cell activation and inflammatory signature in SLE.

INTRODUCTION

Patients with SLE have an increased risk of infections and infection-related mortality, which may be associated with disturbances in immune cell populations. Despite extensive research, findings regarding T-cell and B-cell alterations in SLE remain inconsistent. Therefore, we analysed peripheral blood immune cell subpopulations and their molecular profiles in patients with SLE with renal involvement compared with healthy controls (HCs).

METHODS

The phenotype and gene expression of lymphocytes from patients with SLE and lupus nephritis and healthy donors were assessed using flow cytometry and quantitative PCR. Exploratory multivariate and treatment-sensitivity analyses were performed to evaluate global immune patterns and potential treatment-related confounding.

RESULTS

Patients with SLE exhibited a decreased proportion of helper T (Th) cells and an increased percentage of cytotoxic T (Tc) cells compared with HC, accompanied by a reduced CD4/CD8 ratio. The percentages of CD4+CD28+ and CD8+CD28+ T cells were lower and correlated with disease duration, whereas the proportions of activated HLA-DR+ Th and Tc cells were increased. Serum interleukin (IL)-6 and IL-10 levels were elevated in patients with SLE. In addition, both T and B cells displayed increased expression of genes associated with inflammatory and interferon-related responses, including TBX21, APOBEC3G, IRF8 and ISG15. Exploratory multivariate profiling suggested coordinated immune activation patterns in SLE, characterised by enhanced T-cell activation, elevated inflammatory cytokines and plasmablast expansion, alongside reduced CD28+ T-cell subsets. Treatment-sensitivity analyses indicated that selected immune parameters may be influenced by glucocorticoid exposure and disease duration.

CONCLUSIONS

Patients with SLE with renal involvement show coordinated disturbances in T-cell and B-cell compartments linked to chronic immune activation, interferon-related responses and disease duration. These findings support the relevance of integrated immune profiling in SLE but should be interpreted as exploratory and require validation in larger longitudinal cohorts.