外周血IFN-γ的检测在结核分枝杆菌潜伏感染诊断中的价值

Evaluation of diagnostic screen of latent Mtb.infection by measuring of antigen specific-IFN-γ response using in-house Elispot

目的探讨利用酶联免疫斑点(Elispot)法检测外周血结核抗原特异性γ干扰素(IFN-γ)应答反应在诊断结核分枝杆菌潜伏感染的价值。方法将150例健康者按结核暴露程度分成4级,采用Elispot技术检测其外周血单个核细胞(PBMC)结核菌抗原特异性IFN-γ分泌水平;其中111例进行结核菌素皮试(PPD皮试);39例采用全血干扰素试剂(Quantiferon-TB-Gold,QFT-G)进行IFN-γ分泌水平的平行检测。结果采用Elispot检测结果显示体外IFN-γ应答反应水平与结核菌暴露程度成正相关(r=0.4155,P<0.0001),不同暴露程度分级的IFN-γ应答阳性率分别是:4级(55.6%)、3级(33.3%)、2级(16.7%)、1级(6.8%)。不同暴露程度分级与PPD皮试结果的相关性没有统计学意义(r=0.1206,P=0.2073);不同暴露程度分级的PPD皮试反应阳性率分别为4级(33.3%)、3级(27.8%)、2级(11.1%)、1级(22.0%)。对Elispot检测结果与QTF-G检测结果进行平行比较分析,两种方法检测结果没有统计学差异(χ2=0.125,P=0.7237)。结论外周血结核抗原特异性γ干扰素(IFN-γ)应答反应水平与结核菌暴露程度成正相关,Elispot检测体外IFN-γ应答反应在诊断结核分枝杆菌潜伏感染的价值优于PPD皮试,可以用于对潜伏感染者的筛查。

Objective To investigate the application of interferon-gamma （IFN-γ） measurement on diagnosis of latent Mycobacterium tuberculosis infection by using in-house Elispot. Methods 150 subjects were divided into four classes according to the degree of exposure to Mtb. Antigen specific-IFN response were determined in PBMCs by using in-house Elispot ;Among them 111 subjects were received PPD skin test,and 39 subjects were tested with the whole-blood IFN-γ assay（ Quantiferon-TB-Gold, QFT-G）. Result Significant correlation between the level of IFN-γ and the degree of exposure to M. tb was observed（r = 0. 4155, P 〈 0. 0001 ）. The proportion of positive responses to the in-house Elispot in four classes were 55.6% in class 4,33.3% in class 3,16. 7% in class 2,6. 8% in class 1 respectively. No significant correlation was founded between the result of PPD skin test and the degree of exposure to M. tb （r = 0. 1206, P = 0. 2073 ）. The proportion of positive responses to PPD skin test in four classes were 33.3% in class 4,27. 8% in class 3,11.1% in class 2,22. 0% in classl respectively. The comparative study indicated that there was no statistical difference between the result of in-house Elispot and QTF-G assay （ P = 0. 7237）. Conclusion It demonstrated that the IFN-γresponse was positive correlation to the degree of the exposure of M. tb. The in-house Elispot assay was better than the PPD skin test for screen of latent M. tb infection and it was available to screen of latent M. tb infection.