哮喘病人树突状细胞产生IL-12的变化及对Th1/Th2平衡的影响

Change of Interleukin-12 Production by Dendrition Cells in Asthmatic Patients and Its Influence on Th1/Th2 Balance

目的 :探讨过敏性哮喘病人和正常人外周血单个核细胞 (PBMC)来源树突状细胞 (dendriticcell ,DC)产生IL 12的差异 ,及其对Th1/Th2平衡的影响。方法 :分别取缓解期哮喘患者 (哮喘组 )和正常人 (对照组 )外周血经Ficoll和不连续密度梯度离心法获取贴壁细胞 ,经GM CSF和IL 4体外培养为不成熟DC(iDC) ,加入LPS刺激使其发育为成熟DC(mDC)。另取脐血同上方法获得非贴壁细胞 ,分别加CD4单抗和CD4 5RA单抗及磁珠分离得到初始T淋巴细胞 (Th0 )。两组mDC分别和Th0共培养 ,通过ELISA法检测mDC分泌的IL 12和T淋巴细胞(TC)分泌的IFN γ和IL 4的含量。结果 :①哮喘组PBMC来源DC产生IL 12P70及其亚单位P4 0均较对照组显著减少 (P均 <0 .0 1)。②DC及其IL 12致Th0分化 ,哮喘组TC释放IL 4较对照组显著增多 (P <0 .0 1) ;相反 ,IFN γ较对照组减少 (P <0 .0 5 )。③哮喘组和对照组IL 12P70和IFN γ之间均呈正相关关系 (分别P <0 .0 1,P<0 .0 5 ) ;两组IL 12P70和IL 4均呈负相关关系 (P均 <0 .0 1)。结论 :由于哮喘病人DC功能缺陷 ,产生IL 12减少导致Th2优势分化 ,从而使Th1/Th2平衡向Th2倾斜 ,合成IL 4增多和IFN γ减少 ,后者是哮喘发生的重要机制之一。

Objective: To explore the difference of IL-12 produced by human peripherial blood monocyte(PBMC)-derived dentritic cell (DC) between in asthmatic subjects and in healthy volunteers,and its influence on Th1/Th2 balance. Methods: Adherent cells were isolated from peripherial blood samples in asthmatic patients in remission and in healthy volunteers by Ficoll and noncontinuous density gradient centrifugation and were cultured with GM-CSF and IL-4 as immature DC(iDC).Cells were stimulated with LPS as mature DC(mDC). Nonadherent cells were obtained from umbilical cord blood by idem methods,and primitiveT cell(Th0) were sorted by adding anti-CD4 and anti-CD45RA in non-adherent cells respectively with magnetic microbeads.Th0 and mDC from asthmatic group and control group were cocultured respectively in complete RPMI1640 media.IL-12 released by mDC and IL-4 and IFN-γ produced by T cells(TC) were measured by ELISA. Results: ① The levels of IL-12P70 and P40 produced by DCs in asthmatic subjects group were all significantly lower than those in healthy control group(all P< 0.01 ).② IL-4 production by TCs which were primed by DCs from those cases with asthma was significantly increased comparing with that from control group( P< 0.01),while IFN-γ in patients group was reduced comparing with that in control group( P< 0.05). ③ The level of IL-12 was positively correlated to IFN-γ in either patients group or control group( P< 0.01,P< 0.05 respectively),and negatively correlated to IL-4 in both groups(all P< 0.01 ). Conclusion: Because of diminished IL-12 production,DC preferentially induces Th2 cell development which shifts Th1/Th2 balance towards Th2 resulting in increased IL-4 production and reduced IFN- γproduction by TCs,which is one of important pathogenesis for asthma.