Alternatively activated macrophages (M2) exert anti-inflammatory effects and are crucial for keeping balance between protective and destructive cell-mediated immunity in healing phase of inflammation. Two members of the interferon regulatory factors family, IRF5 and IRF4, are known to promote M1 or M2 phenotype, respectively. Our study aimed to analyse the effectiveness of the M2 differentiation process in vitro (achieved by IL-4 stimulation) and its relationship to the stage of type 1 diabetes mellitus (DM1) in juvenile patients. To identify the basic changes in M2 phenotype, we examined the expression of the surface CD206, CD14, CD86 molecules, intracellular IRF4 and IRF5 transcription factors as well as IL-10 and TNFα intracellular production. Ten newly diagnosed (ND-DM1) and ten long-standing (LS-DM1) patients were enrolled into the study. The control group consisted of six children. We observed a significantly higher number of unpolarised CD206+CD14+ cells in the M2 cultures of DM1 subjects when compared to healthy ones. Examined cells presented common features with M1 macrophages (high levels of the CD14/CD86/IRF5 markers); however, they were weak TNFα producers in ND-DM1 patients. For the first time, we have revealed dysregulated IRF4/IRF5 axis in the analysed subpopulation derived from diabetic patients. Additionally, monocytes of ND-DM1 children were still able to differentiate into regulatory IL-10+ M2 macrophages, while this process was highly limited in LS-DM1 patients. Summarising, we suggest that the M2 polarisation process is less effective in DM1 patients than in healthy subjects and it may vary depending on the stage of disease. It can be concluded that in vitro differentiated M2 macrophages may be used in the future as inflammatory inhibitors for adoptive therapy experiments in ND-DM1 subjects.

中文翻译：

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新诊断的DM1少年患者的单核细胞易于分化为调节性IL-10 + M2巨噬细胞。

另外，活化的巨噬细胞（M2）发挥抗炎作用，对于在炎症的治愈阶段保持保护性和破坏性细胞介导的免疫之间的平衡至关重要。已知干扰素调节因子家族的两个成员IRF5和IRF4分别促进M1或M2表型。我们的研究旨在分析体外M2分化过程的有效性（通过IL-4刺激实现）及其与青少年患者1型糖尿病（DM1）阶段的关系。为了确定M2表型的基本变化，我们检查了表面CD206，CD14，CD86分子，细胞内IRF4和IRF5转录因子以及IL-10和TNFα细胞内产生的表达。十名新诊断的（ND-DM1）和十名长期的（LS-DM1）患者被纳入研究。对照组由六个孩子组成。与健康人相比，我们观察到DM1受试者的M2培养物中非极化CD206 + CD14 +细胞的数量明显增加。检查的细胞呈现出具有M1巨噬细胞的共同特征（高水平的CD14 / CD86 / IRF5标记）；然而，它们是ND-DM1患者中弱的TNFα产生者。首次，我们揭示了来自糖尿病患者的分析亚群中IRF4 / IRF5轴失调。此外，ND-DM1儿童的单核细胞仍能够分化为调节性IL-10 + M2巨噬细胞，而LS-DM1患者的这一过程受到高度限制。总而言之，我们建议DM1患者的M2极化过程不如健康受试者有效，并且它可能根据疾病的阶段而变化。