TLR-9/MyD88信号通路在继发性噬血细胞性淋巴组织细胞增多症中发病机制研究

TLR-9/MyD88信号通路的持续激活可产生大量炎症因子造成机体各器官组织损伤，该信号通路是否参与继发性噬血细胞性淋巴组织细胞增多症（sHLH）的发病尚不清楚。我们发现sHLH患者外周血CD14+单核-巨噬细胞内TLR-9 mRNA、外周血sTLR-4、外周血的CD4+CD25+CD127-Treg均较正常对照组显著升高（p<0.05），TLR-9 mRNA和Treg在有效治疗后下降（P<0.05），提出假说：1. TLR-9/MyD88在单核-巨噬细胞系统内的激活直接参与sHLH的发生？2. TLR-9/MyD88可能通过调控Treg的数量和功能影响sHLH的疾病过程？我们用RAW264.7细胞系、正常供者Treg、sHLH动物模型及患者外周血和骨髓，采用FCM、RT-PCR、Western-Blot及免疫共沉淀等方法，探索持续TLR-9/MyD88信号通路活化在sHLH中的致病机制。

Hemophagocytic lymphohistiocytosis (HLH) is a clinical syndrome characterized by an uncontrolled proliferation of an activated monocyte-macrophage system that secretes high amounts of inflammatory cytokines and causes severe inflammation. Continual activating of TLR-9/MyD88 signal pathway can result in large amounts of cytokine release. However, whether this pathway is involved in the pathogenesis of sHLH is unclear. Our previous study demonstrated that peripheral CD14+ monocyte-macrophage TLR-9 mRNA in sHLH patients were significantly higher than those in healthy controls (p<0.05); The sTLR-4 in the peripheral blood were higher than those in healthy controls, too (p<0.05). In addition, we also found that peripheral blood CD4+CD25+CD127-Treg were higher than those in healthy controls and the level of Treg cells in post-treatment patients was significantly reduced compared to those pre-treatment (p<0.05). Based on these findings, we purpose the following hypothesis: (1): Whether TLR-9/MyD88 in monocyte-macrophage system activation is directly involved in the occurrence of sHLH? (2): Whether TLR-9 / MyD88 activation may affect the sHLH progression by regulating the level and function of Treg? To address these issues, we will use RAW264.7 monocyte macrophage cell lines, Treg of healthy controls, sHLH animal models, peripheral blood and bone marrow samples of sHLH patients, to further explore the pathogenesis and molecular mechanisms of TLR-9/MyD88 signaling pathway in sHLH. Additional methods such as Flow cytometry, RT-PCR, Western-Blot, and Co-immunoprecipitation will also be used in this study.