Pathogenesis of mycobacterial infection has been extensively studied determining the fundamental role of host immunocompetence in disease progression. Cellular adaptive immunity, in particular CD4+ cells, has shown to be crucial in the host defence. A role of cytotoxic lymphocytes and humoral immunity has also been established. However, few studies have been performed in low endemic countries on immunological correlates of tuberculosis in paediatric patients. The present study aims to fill this gap analysing the distribution and the absolute values of the main lymphocyte subpopulations (CD3+, CD4+, CD8+, CD19+ and CD16+/CD56+) in the different stages of tubercular infection in human immunodeficiency virus-negative children living in low tubercular endemic countries. Results obtained in children with latent tuberculosis, active tuberculosis and healthy controls were compared. Moreover, quantitative analysis of interferon-γ levels of mitogen-induced response was carried out within the different study groups. The aim of this analysis was to enforce the comprehension of immune modifications subsequent to Mycobacterium tuberculosis infection. The major finding of our study was CD3+ and CD4+ absolute and percentage depletion in children with active tuberculosis versus healthy controls. Moreover, severe forms of active tuberculosis showed a marked reduction in the CD4+ percentage in the context of a systemic impairment which affects globally the absolute count of all peripheral lymphocyte subsets tested. A relative increase of natural killer cells was proved in infected patients, whereas no differences in B cells among the study groups were detected. Mitogen-induced interferon-γ levels were significantly higher in children with latent tuberculosis when compared to active tuberculosis and healthy controls, demonstrating effective immune activation in those patients able to control the infection.

中文翻译：

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结核感染和疾病中的CD3，CD4，CD8，CD19和CD16 / CD56阳性细胞：儿童的特殊特征。

已经广泛研究了分枝杆菌感染的发病机制，以确定宿主免疫能力在疾病进展中的基本作用。细胞适应性免疫，特别是CD4 +细胞，在宿主防御中已显示出至关重要的作用。还已经确定了细胞毒性淋巴细胞和体液免疫的作用。但是，在低流行国家中，很少有关于小儿患者结核病免疫相关性的研究。本研究旨在填补生活在低水平的人类免疫缺陷病毒阴性儿童结核感染不同阶段中主要淋巴细胞亚群（CD3 +，CD4 +，CD8 +，CD19 +和CD16 + / CD56 +）的分布和绝对值，以填补这一空白结核病流行国家。儿童潜伏性结核病获得的结果，比较活动性结核病和健康对照。此外，在不同研究组中进行了干扰素-γ水平的丝裂原诱导反应的定量分析。该分析的目的是增强对结核分枝杆菌感染后免疫修饰的理解。我们研究的主要发现是活动性结核病儿童与健康对照组的CD3 +和CD4 +绝对耗竭和百分比耗竭。此外，在系统性损害的情况下，严重形式的活动性肺结核显示CD4 +百分比显着降低，这会整体影响所测试的所有外周淋巴细胞亚群的绝对计数。在感染的患者中证明了自然杀伤细胞的相对增加，而在研究组之间未发现B细胞的差异。