Dexamethasone promotes renal fibrosis by upregulating ILT4 expression in myeloid-derived suppressor cells.

Studies have shown that adoptive transfer of myeloid-derived suppressor cells (MDSCs) can alleviate various inflammatory diseases, including glomerulonephritis, but the long-term effects of the transferred MDSCs are still unclear. In addition, although glucocorticoids exert immunosuppressive effects on inflammatory diseases by inducing the expansion of MDSCs, the impact of glucocorticoids on the immunosuppressive function of MDSCs and their molecular mechanisms are unclear. In this study, we found that adoptive transfer of MDSCs to doxorubicin-induced focal segmental glomerulosclerosis (FSGS) mice for eight consecutive weeks led to an increase in serum creatinine and proteinuria and aggravation of renal interstitial fibrosis. Similarly, 8 weeks of high-dose dexamethasone administration exacerbated renal interstitial injury and interstitial fibrosis in doxorubicin-induced mice, manifested as an increase in serum creatinine and proteinuria, collagen deposition and α-SMA expression. On this basis, we found that dexamethasone could enhance MDSC expression and secretion of the fibrosis-related cytokines TGF-ß and IL-10. Mechanistically, we revealed that dexamethasone promotes the expression of immunoglobulin-like transcription factor 4 (ILT4), which enhances the T-cell inhibitory function of MDSCs and promotes the activation of STAT6, thereby strengthening the expression and secretion of TGF-ß and IL-10. Knocking down ILT4 alleviated renal fibrosis caused by adoptive transfer of MDSCs. Therefore, our findings demonstrate that the role and mechanism of dexamethasone mediate the expression and secretion of TGF-ß and IL-10 in MDSCs by promoting the expression of ILT4, thereby leading to renal fibrosis.

[Factors Influencing the efficacy of Plasma Exchange in the Treatment of Immune Thrombocytopenic Purpura].

OBJECTIVE: To observe the efficacy of plasma exchange in the treatment of patients with immune thrombocytopenic purpura (ITP), and to analyze the factors influencing the efficacy of plasma exchange in the treatment of ITP. METHODS: The medical records of 39 ITP patients who were treated effectively by plasma exchange in Huai'an First People's Hospital from January 2013 to January 2021 were retrospectively analyzed, and they were set as the effective group. In addition, the medical records of 39 ITP patients who were treated ineffective by plasma exchange during the same period in our hospital were collected, and they were set as the ineffective group. The general data such as sex and age of patients and laboratory indicators on admission were collected and recorded. The possible influencing factors were included, and Logistic regression analysis was used to examine the influencing factors of efficacy of plasma exchange in the treatment of ITP. RESULTS: The serum levels of IL-6, IL-18 and B lymphocyte activating factor (BAFF) on admission in the ineffective group were significantly higher than those in the effective group, and the proportions of Helicobacter pylori (HP) infection and splenomegaly were significantly higher than those in the effective group (P<0.05). There was no statistical significantly difference in sex, age and other data between the two groups (P>0.05). After single factor analysis, multiple regression model was established, which showed that splenomegaly, HP infection and the over expression of serum IL-6, IL-18 and BAFF on admission might be the influencing factors of ineffective treatment of ITP by plasma exchange (OR>1, P<0.05). CONCLUSION: The over expression of serum IL-6, IL-18, BAFF, splenomegaly and HP infection on admission may be the influencing factors resulting in the ineffective treatment of plasma exchange in ITP.