Immunodeficiency and Histiocytosis Program, Division of Bone Marrow Transplantation, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA.
Front Immunol. 2013 Mar 22;4:72. doi: 10.3389/fimmu.2013.00072. eCollection 2013.
Patients with hemophagocytic lymphohistiocytosis (HLH) exhibit immune hyper-activation as a consequence of genetic defects in secretory granule proteins of cytotoxic T lymphocytes (CTL) and natural killer (NK) cells. Murine models of HLH demonstrate significant activation of CTL as central to the disease pathogenesis, but evaluation of CTL and NK activation in children with HLH or inflammatory conditions is not well described. CD8 T cells only express granzyme B (GrB) following stimulation and differentiation into CTL; therefore, we reasoned that GrB expression may serve as a signature of CTL activation. It is unknown whether human NK cells are similarly activated in vivo, as marked by increased granule proteins. Perforin and GrB levels are measured in both CTL and NK cells by flow cytometry to diagnose perforin deficiency. We retrospectively compared GrB expression in blood samples from 130 children with clinically suspected and/or genetically defined HLH to age-matched controls. As predicted, CD8 expressing GrB cells were increased in HLH, regardless of genetic etiology. Remarkably, the GrB protein content also increased in NK cells in patients with HLH and decreased following immunosuppressive therapy. This suggests that in vivo activation of NK cells occurs in hyper-inflammatory conditions. We conclude that increased detection of GrB in CTL and NK are an immune signature for lymphocyte activation in HLH, irrespective of genetic subtype and may also be a useful measure of immune activation in other related conditions.
噬血细胞性淋巴组织细胞增生症（HLH）患者表现出免疫过度激活，这是细胞毒性 T 淋巴细胞（CTL）和自然杀伤（NK）细胞分泌颗粒蛋白遗传缺陷的结果。HLH 的小鼠模型表明 CTL 的显著激活是疾病发病机制的核心，但对 HLH 或炎症性疾病患儿的 CTL 和 NK 激活的评估尚未得到很好的描述。CD8 T 细胞仅在受到刺激并分化为 CTL 后才表达颗粒酶 B（GrB）；因此，我们推断 GrB 表达可能是 CTL 激活的标志。尚不清楚人类 NK 细胞是否同样在体内被激活，其特征是颗粒蛋白增加。通过流式细胞术测量 CTL 和 NK 细胞中的穿孔素和 GrB 水平，以诊断穿孔素缺陷。我们回顾性比较了 130 名临床疑似和/或遗传定义的 HLH 患儿与年龄匹配对照的血液样本中的 GrB 表达。正如预测的那样，无论遗传病因如何，HLH 中 CD8 表达 GrB 的细胞均增加。值得注意的是，HLH 患者 NK 细胞中的 GrB 蛋白含量也增加，并且在免疫抑制治疗后降低。这表明 NK 细胞在体内的激活发生在炎症过度活跃的情况下。我们得出结论，CTL 和 NK 中 GrB 的检测增加是 HLH 中淋巴细胞激活的免疫特征，与遗传亚型无关，也可能是其他相关疾病中免疫激活的有用指标。
