Type 2 autoimmune hepatitis (AIH-2) is a rare disease presenting in early childhood. The immunopathogenetic mechanisms are poorly characterized, although a defect of regulatory T cells (Treg) has been shown. There is virtually no information on innate immune responses and natural killer (NK) cells in particular. We have performed an extended immunophenotypic and functional analysis of NK cells in children with AIH-2. We show that NK cell frequency is reduced in this setting and that the balance between NK activating and inhibitory receptors is skewed toward activation. More importantly, NK cells display an altered cytokine pattern characterized by increased IFNγ and reduced IL2 production which could contribute to impaired Treg function. Exposure of mononuclear cells to IL2 resulted in normalization of NK IFNγ production. Thus, our findings support treatment of AIH-2 with low-dose IL2, which would result in normalization of NK cell function and expansion of the Treg cell subset.

2型自身免疫性肝炎（AIH-2）是一种在儿童早期出现的罕见疾病。尽管已显示出调节性T细胞（Treg）的缺陷，但免疫病理机制的特征却很差。几乎没有关于先天免疫应答和自然杀伤（NK）细胞的信息。我们已经对AIH-2儿童的NK细胞进行了扩展的免疫表型和功能分析。我们显示在这种情况下NK细胞的频率降低，并且NK激活和抑制受体之间的平衡偏向激活。更重要的是，NK细胞表现出改变的细胞因子模式，其特征在于IFNγ增加和IL2生成减少，这可能导致Treg功能受损。单核细胞暴露于IL2导致NKIFNγ产生正常化。因此，