Alcohol-associated hepatitis (AH) is often diagnosed at advanced stages, and severe AH usually carries poor prognosis and high short-term mortality. In addition, it is challenging to understand the molecular mechanisms of immune dysregulation and inflammation in AH due to the cellular complexity and heterogeneity. Using single-cell RNA sequencing, previous studies found that AH causes dysfunctional innate immune response in monocytes, involving activation of pattern recognition receptors (PRRs) and cytokine signaling pathways. To better understand the coordinated systemic immune response in AH patients, we performed combined single-cell transcriptome, cell-surface protein, and lymphocyte antigen receptor analysis of peripheral blood mononuclear cell (PBMC) samples. Our results showed inflammatory cytokines and chemokines were highly expressed in AH, including IL-2, IL-32, CXC3R1 and CXCL16 in monocytes and NK cells, whereas HLA-DR genes were reduced in monocytes. In addition, we also found altered differentiation of T-helper cells (T_H1 and T_H17), which could further lead to neutrophil recruitment and macrophage activation. Lastly, our results also suggest impaired NK-cell activation and differentiation in AH with reduced gene expression of KLRC2 and increased gene expression of KLRG1. Our findings indicate different mechanisms may be involved in impaired immune and inflammatory responses for the cellular subtypes of the PBMCs in AH.

酒精相关性肝炎（AH）通常在晚期才被诊断出来，严重的 AH 通常预后较差，短期死亡率较高。此外，由于细胞的复杂性和异质性，了解 AH 中免疫失调和炎症的分子机制具有挑战性。之前的研究通过单细胞 RNA 测序发现，AH 会导致单核细胞先天免疫反应功能失调，涉及模式识别受体 (PRR) 和细胞因子信号通路的激活。为了更好地了解 AH 患者协调的全身免疫反应，我们对外周血单核细胞 (PBMC) 样本进行了单细胞转录组、细胞表面蛋白和淋巴细胞抗原受体的联合分析。我们的结果显示，炎症细胞因子和趋化因子在 AH 中高表达，包括单核细胞和 NK 细胞中的 IL-2、IL-32、CXC3R1 和 CXCL16，而单核细胞中的 HLA-DR 基因减少。此外，我们还发现 T 辅助细胞（TH 1 和 T H 17）的分化发生改变_，这_可能进一步导致中性粒细胞募集和巨噬细胞激活。最后，我们的结果还表明，AH 中 NK 细胞活化和分化受损，KLRC2 基因表达减少，KLRG1 基因表达增加。我们的研究结果表明，AH 中 PBMC 细胞亚型的免疫和炎症反应受损可能涉及不同的机制。