系统性红斑狼疮患者血清α干扰素和白细胞介素6共同作用对造血干细胞定向分化为树突状细胞的影响

背景:系统性红斑狼疮与树突状细胞的功能活化密切相关.在体内,树突状细胞来源于造血干细胞,其分化成熟的过程受多种因素的影响.系统性红斑狼疮患者血清中存在细胞因子网络失调,以往研究多关注于单一因子的参与作用.目的:课题创新性提出和观察系统性红斑狼疮患者血清α干扰素和自细胞介素6共同作用下对CD34~+造血干细胞定向分化为树突状细胞的影响.设计、时间及地点:分组对比观察,完全随机细胞学体外实验,于2006-05/2008-10在南京医科大学微生物与免疫学实验室完成.材料:外周血标本取自50例就诊于南京医科大学第一附属医院风湿免疫科的系统性红斑狼疮患者,以及30例南京医科大学的健康志愿献血者.15份脐血标本取自南京医科大学附属南京妇幼保健院健康足月顺产的新生儿,产妇及其家属均对实验知情同意.方法:无菌采集系统性红斑狼疮患者和正常对照者的外周静脉血,根据正常人血清中α干扰素、白细胞介素6的浓度,采用百分位数法求得血清α干扰素、白细胞介素6浓度的95%参考值范围,并以浓度超过此范围为异常升高.取新生儿脐血,Ficoll-Hypaque密度梯度离心法分离脐血单个核细胞,免疫磁珠法纯化CD34~+造血干细胞,并诱导其定向分化为树突状细胞.在培养过程中设立6组,分别加入:正常对照血清、α干扰素升高的系统性红斑狼疮血清、白细胞介素6升高的系统性红斑狼疮血清、α干扰素和白细胞介素6同时升高的系统性红斑狼疮血清、混合α干扰素及白细胞介素6中和抗体的系统性红斑狼疮血清、混合外源性α干扰素和白细胞介素6的正常对照者血清,各组血清体积分数均为10%,培养14 d.主要观察指标:流式细胞仪检测树突状细胞的表型,ELISA法检测树突状细胞分泌细胞因子的水平,混合淋巴细胞反应检测树突状细胞刺激同种异体T细胞增殖的能力,及其对T细胞亚群分化率影响.结果:①与正常血清对照比较,α干扰素、白细胞介素6及二者同时升高的系统性红斑狼疮血清、混合外源性α干扰素和白细胞介素6的正常对照者血清诱导培养的树突状细胞其HLA-DR,CD80,CD86的表达均明显升高(P＜0.05),分泌白细胞介素12的水平均明显降低(P＜0.05),刺激T细胞增殖能力均明显增强(P＜0.05).混合α干扰素及白细胞介素6中和抗体的系统性红斑狼疮血清诱导培养的树突状细胞上述各项指标均恢复至正常血清对照水平.②与正常血清对照比较,白细胞介素6升高的系统性红斑狼疮血清其CD3~+CD8~-IFN-γ~+、CD3~+CD8~-IFN-γ~+细胞亚群百分率明显下降(P＜0.05):α干扰素升高的系统性红斑狼疮血清、α干扰素和白细胞介素6同时升高的系统性红斑狼疮血清、混合外源性α干扰素和白细胞介素6的正常对照者血清其CD3~+CD8~-IFN-γ~+和CD3~+CD8~+IFN-γ~+细胞亚群百分率均明显升高(P＜0.05).结论:系统性红斑狼疮血清α干扰素和白细胞介素6的共同作用对CD34+造血干细胞定向分化为树突状细胞产生了异常影响,可促进树突状细胞的表型成熟和功能活化,并间接影响T细胞亚群的分化,可能参与系统性红斑狼疮的发病.

Effects of combined action of serum interferon alpha and interleukin-6 from systemic lupus erythematosus patients on the differentiation and maturation of dendritic cells derived from hematopoietic precursor cells

BACKGROUND:Systemic erythematosus lupus (SLE) is closely associated with activity of dendritic cells (DCs) function.DCs derive from hematopoietic precursor cells (HPCs) in vivo and many factors might affect the differentiation and maturation of DCs.The cytokine network was in disturbance and the levels of various cytokines were anomalous in SLE serum.Previous studies mainly addressed effects of single factors.OBJECTIVE:To investigate the effects of joint action of serum interferon (IFN)-α and interieukin (IL)-6 in the serum of SLE patients on the differentiation and maturation of DCs derived from CD34~+ HPCs.DESIGN,TIME AND SETTING:The grouping,controlled and completely random designed study was performed at the Department of Microbiology and Immunology,Nanjing Medical University from May 2006 to October 2008.MATERIALS:Peripheral blood samples were collected from 50 SLE patients from the Department of Rheumatology,First Affiliated Hospital of Nanjing Medical University and 30 healthy volunteers from Nanjing Medical University.Cord blood samples were collected from 15 full-term normal delivery neonates from Nanjing Maternity and Children Health Care Hospital Affiliated to Nanjing Medical University.Informed consent was obtained from all patients and their family members.METHODS:Peripheral blood samples were collected from SLE patients and healthy volunteers.According to serum IFN-α and IL-6 concentrations of normal person,95% reference value range of serum IFN-α and IL-6 concentrations were calculated by the method of percentiles.Above this range represented abnormal increase.Cord blood mononuclear cells were harvested by Ficoll-Hypaque density gradient centrifugation.CD34~+HPCs were purified from cord blood by magnetic cell sorting system (MACS),and cultured to differentiate to DCs.There were 6 groups in this study.Normal serum,SLE serum with elevated levels of IFN-α,SLE serum with elevated levels of IL-6,SLE serum with elevated levels of IFN-α and IL-6,SLE serum with anti-IFN-α and anti-IL-6 neutralizing antibodies,or normal serum with exogenous IFN-α and IL-6 were respectively added to the culture medium in each group.10% volume fraction serum was used in each group,for totally 14 days incubation.MAIN OUTCOME MEASURES:The phenotype of DCs was analyzed by flow cytometry (FCM).Cytokine production was assessed by ELISA.The capacity of DCs to stimulate allogenic T lymphocyte proliferation and to regulate T cell differentiation was evaluated in a mixed lymphocyte reaction (MLR).RESULTS:Compared with normal serum,HLA-DR,CD80 and CD86 expression was significantly increased in the medium containing SLE serum with elevated levels of IFN-α,SLE serum with elevated levels of IL-6,SLE serum with elevated levels of IFN-α and IL-6 and normal serum with exogenous IFN-α and IL-6 (P＜0.05),whereas IL-12 levels were significantly decreased (P＜0.05),and capacity of DCs to stimulate allogenic T lymphocyte proliferation was significantly enhanced (P＜0.05).Above-mentioned indexes recovered to a normal level in the medium containing SLE serum with anti-IFN-α and anti-IL-6 neutralizing antibodies.Compared with normal serum,proportion of both CD3~+CD8~-IFN-γ~+ and CD3~+CD8~+IFN-γ~+ T cell subsets was significantly reduced in the medium containing SLE serum with elevated levels of IL-6 (P＜0.05).However,proportion of both CD3~+CD8~-IFN-γ~+ and CD3~+CD8~+IFN-γ~+ T cell subsets was significantly increased in the medium containing SLE serum with elevated levels Of IFN-α,SLE serum with elevated levels of IFN-α and IL-6,normal serum with exogenous IFN-α and IL-6 (P＜0.05).CONCLUSION:The joint action of IFN-α and IL-6 in SLE serum promotes the differentiation and maturation of DCs derived from CD34+HPCs and affects the DC-mediated T cell differentiation,which might contribute to the pathogenesis of SLE.