Expression profile of PU.1 in CD4⁺T cells from patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with complex genetic predisposing factors involved. PU.1 is an important member of the ETS transcription factors family which has diverse functions such as regulating the proliferation, differentiation of immune cells and multiple inflammatory cytokines. Previous studies preliminary explored the relation between PU.1 and SLE. To further explain the potential role of PU.1 in the pathogenesis of SLE, 40 SLE patients and 20 age-sex matched healthy controls (HC) were recruited in this study. Flow cytometry was used to test the percentages of CD4⁺PU.1⁺T cells in peripheral blood mononuclear cells (PBMCs) from patients with SLE and HC. Expression levels of PU.1 mRNA in CD4⁺T cells from SLE patients and HC were analyzed by real-time transcription-polymerase chain reaction. Expression levels of plasma IL-1β, IL-9, IL-18, IL-6, IFN-α, TNF-α, IL-10 and TGF-β1 were measured by enzyme-linked immunosorbent assay. The percentage of CD4⁺PU.1⁺T cells in PBMCs from patients with SLE was significantly higher than that from HC (P < 0.001). In addition, the PU.1 mRNA expression in CD4⁺T cells from SLE patients was increased than that from HC (P = 0.002). In SLE patients, no significant correlation was found between the percentage of CD4⁺PU.1⁺T cells and the expression of PU.1 mRNA in CD4⁺T cells (P > 0.05). Associations of PU.1 mRNA expression in CD4⁺T cells with major clinical and laboratory parameters of SLE patients were also analyzed, but no significant correlations were found. Consistent with previous studies, SLE patients had increased IL-1β, IL-18, IL-6, IFN-α, TNF-α and IL-10 plasma concentrations than HC (P < 0.01). The expression level of plasma TGF-β1 was significantly decreased in SLE patients than in HC (P < 0.001). In SLE patients, the expression level of IL-1β was positive correlated with PU.1 mRNA expression in CD4⁺T cells (P = 0.001). Our study first time evaluated the expression profile of PU.1 in CD4⁺T cells from SLE patients confirming that PU.1 may participate in the pathogenesis of SLE.