Laboratory of Vaccinology and Mucosal Immunity, Université Libre de Bruxelles, Brussels, Belgium.
Pediatric Department, Centre Hospitalo-Universitaire Saint-Pierre, Brussels, Belgium.
Front Immunol. 2021 Mar 15;12:575519. doi: 10.3389/fimmu.2021.575519. eCollection 2021.
Diagnosis of tuberculosis (TB) in children remains challenging due to unspecific clinical presentation and low bacillary load. In low TB incidence countries, most cases are diagnosed by a contact screening strategy after exposure to an index TB case. Due to the severity of TB in young children, the priority is to determine whether a child is infected or not, whereas differential diagnosis between active TB (aTB) and latent TB constitutes a second step. In Belgium, a low TB incidence country, we prospectively included 47 children with a defined infection status (12 children with aTB, 18 with latent TB, and 17 uninfected) (exploratory cohort), and determined the optimal combinations of cytokines secreted by their peripheral blood mononuclear cells in response to a 5-days stimulation with four different mycobacterial antigens, in an attempt to classify the children according to their infectious status. Correct identification of all infected children was obtained by several combinations of two purified protein derivative (PPD)-induced cytokines (IFN-γ and either GM-CSF, MIP-1α, sCD40L or TNF-α), or by combining PPD-induced IFN-γ with culture-filtrate protein-10 (CFP-10)-induced TNF-α. Alternatively, combining CFP-10-induced TNF-α and IP-10 with heparin-binding haemagglutinin (HBHA)-induced-IFN-γ was more effective in testing recently BCG-vaccinated children or those suspected to be infected with non-tuberculous mycobacteria, providing a correct classification of 97% of the infected children. This combination also correctly classified 98% of the children from a validation cohort comprising 40 infected children and 20 non-infected children. Further differentiation between aTB and children with latent TB was more difficult. Combining ESAT-6-induced MIP1-α and IP-10, CFP-10-induced MIG, and HBHA-induced MIG provided a correct classification of 77% of the children from the exploratory cohort but only of 57.5% of those from the validation cohort. We conclude that combining the measurement of 2-4 cytokines induced by three different mycobacterial antigens allows an excellent identification of infected children, whereas differentiating children with aTB from those with latent TB remains far from perfect.
由于临床表现不特异和细菌载量低，儿童结核病的诊断仍然具有挑战性。在结核病发病率较低的国家，大多数病例是通过接触筛查策略在接触到索引结核病病例后诊断出来的。由于儿童结核病的严重程度，当务之急是确定儿童是否感染，而区分活动性结核病（aTB）和潜伏性结核病则构成了第二步。在比利时，一个结核病发病率较低的国家，我们前瞻性地纳入了 47 名具有明确感染状态的儿童（12 名患有 aTB，18 名患有潜伏性 TB，17 名未感染）（探索性队列），并确定了外周血单个核细胞对四种不同分枝杆菌抗原刺激 5 天产生的细胞因子的最佳组合，试图根据其感染状态对儿童进行分类。通过几种组合可以正确识别所有感染儿童，这些组合包括两种纯化蛋白衍生物（PPD）诱导的细胞因子（IFN-γ和 GM-CSF、MIP-1α、sCD40L 或 TNF-α），或结合 PPD 诱导的 IFN-γ和培养滤过蛋白-10（CFP-10）诱导的 TNF-α。或者，将 CFP-10 诱导的 TNF-α与肝素结合血凝素（HBHA）诱导的 IFN-γ相结合，在检测最近接种过卡介苗的儿童或疑似感染非结核分枝杆菌的儿童时更为有效，对 97%的感染儿童进行了正确分类。这种组合还对包含 40 名感染儿童和 20 名非感染儿童的验证队列中的 98%的儿童进行了正确分类。进一步区分 aTB 和潜伏性 TB 儿童更为困难。将 ESAT-6 诱导的 MIP1-α和 IP-10、CFP-10 诱导的 MIG 和 HBHA 诱导的 MIG 相结合，可对探索性队列中的 77%的儿童进行正确分类，但对验证队列中的儿童仅为 57.5%。我们得出结论，结合三种不同分枝杆菌抗原诱导的 2-4 种细胞因子的测量可以极好地识别感染儿童，而区分 aTB 儿童和潜伏性 TB 儿童远非完美。
