University of São Paulo, Department of Dermatology, São Paulo, Brazil.
Br J Dermatol. 2011 Jun;164(6):1271-9. doi: 10.1111/j.1365-2133.2010.10198.x. Epub 2011 May 11.
Understanding the early events of the immune response, through the activation of plasmacytoid dendritic cells (pDC) by Toll-like receptor (TLR)9-sensing, could contribute to the evaluation of immune dysregulation in chronic idiopathic urticaria (CIU).
We decided to investigate innate immunity in CIU and the mechanisms implicated in the modulation of interferon (IFN)-α production by pDC upon TLR9 activation.
Patients with CIU (n = 31) and healthy control subjects (HC, n = 36) were enrolled in the study. Leucocytes cultured with the TLR9 ligand, CpG type A, or with inhibitory-oligodeoxynucleotide (ODN) were used to determine IFN-α secretion by enzyme-linked immunosorbent assay. Enumeration of pDC, intracellular IFN-α and signal transducers and activators of transcription protein (STAT) (1 and 4) phosphorylation were assessed by flow cytometry. TLR9 and regulatory factor-7 mRNA transcripts were evaluated by real-time polymerase chain reaction. Evidence of pDC in the skin lesions of patients was analysed with immunohistochemistry staining.
The findings show a decreased IFN-α secretion induced by CpG A by leucocytes, due to the diminished IFN-α expression on pDC in CIU. It was mediated by TLR9-activation since inhibitory-ODN further suppressed TLR9-induced IFN-α secretion. A normal pDC percentage and degree of activation by the expression of costimulatory molecules was observed in CIU, with the rare presence of pDC in the skin lesion. In addition, an increased constitutive STAT1 phosphorylation on nonstimulated lymphocytes and a downregulation of TLR9 mRNA transcripts after CpG A activation were verified in patients with CIU.
The findings showed an innate immune response in CIU disturbed by impairment of the pDC response to TLR9 activation.
通过 Toll 样受体 (TLR)9 感应激活浆细胞样树突状细胞 (pDC)，了解免疫反应的早期事件，有助于评估慢性特发性荨麻疹 (CIU) 中的免疫失调。
我们决定研究 CIU 中的先天免疫以及 pDC 在 TLR9 激活后调节干扰素 (IFN)-α 产生所涉及的机制。
招募了 31 名 CIU 患者和 36 名健康对照者 (HC) 参与研究。使用 TLR9 配体 CpG A 或抑制性寡脱氧核苷酸 (ODN) 培养白细胞，通过酶联免疫吸附试验测定 IFN-α 的分泌。通过流式细胞术评估 pDC、细胞内 IFN-α 和信号转导和转录激活因子 (STAT) (1 和 4) 的磷酸化。通过实时聚合酶链反应评估 TLR9 和调节因子-7 mRNA 转录物。通过免疫组织化学染色分析患者皮肤损伤中的 pDC 证据。
研究结果表明，由于 CIU 中 pDC 上 IFN-α 表达减少，CpG A 诱导的白细胞 IFN-α 分泌减少。这是由 TLR9 激活介导的，因为抑制性 ODN 进一步抑制了 TLR9 诱导的 IFN-α 分泌。在 CIU 中观察到 pDC 百分比和共刺激分子表达的正常激活程度，皮肤损伤中 pDC 的存在很少。此外，在 CIU 患者中，还验证了非刺激淋巴细胞中固有 STAT1 磷酸化增加以及 CpG A 激活后 TLR9 mRNA 转录物下调。
研究结果表明，CIU 中的先天免疫反应受到 pDC 对 TLR9 激活反应受损的干扰。
