虽然纯化的蛋白衍生物(PPD)通常用作结核病(TB)感染的皮肤诊断试剂,它不能有效区分卡介苗(BCG)疫苗接种与结核分枝杆菌(MTB)复合体和非结核分枝杆菌感染。新型皮肤试剂ESAT6-CFP10(EC)具有良好的敏感性和特异性,这可以克服与PPD相关的限制。目前,EC皮试反应主要表现为红斑,而PPD主要引起硬结。我们使用豚鼠模型对EC诱导的红斑和PPD诱导的硬结之间的潜在差异进行了比较研究。EC依赖性红斑的大小与PPD诱导的硬结相似,和以单核细胞浸润为特征的炎症反应,巨噬细胞和淋巴细胞,以及组织损伤,出现在注射部位。淋巴细胞包括CD4+T细胞和CD8+T细胞,其释放IFN-γ作为主要细胞因子。EC红斑和PPD硬结均可导致急性期蛋白水平升高,差异途径相似,因此表明主要的诱导免疫途径是相似的。以上结果表明,EC产生的红斑可产生PPD硬结的主要迟发型超敏反应(DTH),提示红斑也可能具有一定的诊断意义,为其作为检测MTB感染的诊断指标提供可能的理论依据。
While purified protein derivative (PPD) is commonly used as skin diagnostic reagent for tuberculosis (TB) infection, it cannot distinguish effectively Bacillus Calmette-Guérin (BCG) vaccination from Mycobacterium tuberculosis (MTB) complex and nontuberculous mycobacteria infection. The new skin reagent ESAT6-CFP10 (EC) has favorable sensitivity and specificity, which can overcome limitations associated with PPD. At present, EC skin test reactions are mainly characterized by erythema, while PPD mainly causes
induration. We conducted a comparative study on the potential differences between EC-induced erythema and PPD-induced
induration using a guinea pig model. The size of EC-dependent erythema was similar to that of PPD-induced
induration, and an inflammatory response characterized by the infiltration of monocytes, macrophages and lymphocytes, as well as tissue damage, appeared at the injection site. The lymphocytes included CD4+ T and CD8+ T cells, which released IFN-γ as the main cytokine. Both EC erythema and PPD
induration could lead to increased levels of acute-phase proteins, and the differential pathways were similar, thus indicating that the main induced immune pathways were similar. The above results indicated that erythema produced by EC could generate the main delayed-type hypersensitivity (DTH) response characteristic of PPD
induration, thereby suggesting that erythema might also have a certain diagnostic significance and provide a possible theoretical basis for its use as a diagnostic indicator for detecting MTB infection.