结核分枝杆菌特异性效应T细胞斑点数鉴别儿童活动性结核病与潜伏结核感染的价值

The value of mycobacterium tuberculosis specific effector T-cell spot counting in differentiating active tuberculosis from latent tuberculosis infection in children

目的通过γ干扰素释放试验探讨结核分枝杆菌特异性效应T细胞斑点数(简称T细胞斑点数)鉴别儿童活动性结核病(TB)与潜伏结核感染(LTBI)的价值。方法纳入T细胞斑点试验(T.SPOT.TB)阳性且未经过抗结核治疗的93例活动性TB(重症TB27例,非重症TB66例)和47例LTBI儿童,根据T.SPOT.TB结果对T细胞斑点数进行比较分析。结果活动性TB组T细胞斑点数中位数84(6～710)显著高于LTBI组17(6～316),P=0.000;非重症TB患儿的T细胞斑点数中位数为99(6～710),显著高于重症TB的44(6～268),P=0.011,也显著高于LTBI组17(6～316),P=0.000;重症TB儿童T细胞斑点数中位数高于LTBI组儿童(44vs17),但差异无统计学意义(P=0.084),T细胞斑点数分布在活动性TB、重症TB、非重症TB和LTBI之间均有较大范围重叠。受试者工作特征曲线分析显示以T细胞斑点数43.5作为区分活动性TB与LTBI的最佳界值,其敏感度与特异度分别为69.9%和70.2%。结论 T细胞斑点数在活动性TB尤其是非重症TB患儿显著高于LTBI儿童;T细胞斑点数的数量可反映体内的结核分枝杆菌负荷,但不能用于区分儿童活动性TB与LTBI。

Objective To evaluate whether there is mycobacterium tuberculosis specific effector T-cell spot counting difference in children with active TB and LTBI through using interferon--y release assays （IGRAs） and whether it can be used to differentiate active tuberculosis（TB） from latent tuberculosis infection（LTBI） or not. Methods A total of 93 active TB cases （27 severe and 66 non-severe cases of tuberculosis） and 47 LTBI cases with positive T. SPOT. TB results but without anti-tuberculosis treatment were included, mycobacterium tuberculosis specific effector T-cell spot counts were analyzed in the two groups. Results The median of spot counts in active TB was significantly larger than that in LTBI, 84 （6 -710 ） vs 17 （6 -316 ） （P = 0. 000 ）, significant difference was also seen between non-severe cases of TB and severe cases,99 （6 -710） vs 44 （6 -268） （P = 0.011 ） , non-severe cases of TB and LTBI （ P = 0. 000） , while there was no significant difference between severe cases of TB and LTBI （ P = 0. 084 ）. There was a large range of overlapping of spot counts distribution between active TB and LTBI, non-severe cases of TB and LTBI, severe cases of TB and LTBI, non-severe and severe cases of TB. Receiver operator characteristic （ROC） curve analysis showed the best cut-off value was 43.5 for T. SPOT. TB in differentiating active TB from LTBI, the sensitivity and specificity were 69.9% and 70.2%, respectively. Conclusions Although mycobacterium tuberculosis specific effector T-cell spot counting in children with active TB especially in non-severe cases of TB is significantly larger than that in LTBI which reflects mycobacterium tuberculosis bacilli load to some extent, it cannot be used to differentiate active TB from LTBI in children.