间变性大细胞淋巴瘤（ALCL）是一种CD30阳性淋巴瘤，占所有小儿T细胞淋巴瘤的20％。目前的一线治疗可以治愈大多数ALCL患者，但10-30％的患者耐药或复发。在这种情况下，液体活检有潜力帮助临床医生进行疾病筛查和治疗反应监测。对20例初诊小儿ALK阳性ALCL患者的血浆小细胞外囊泡（s-EVs）进行的小RNA测序分析显示，与非复发患者相比，复发患者的s-EVs中富集了七个miRNA。 miR-146a-5p和miR-378a-3p在单变量和多变量分析中均显示出负面预后影响，可能与let-7g-5p一起构成了早期识别高风险患者的miRNA面板。其中，miR-146a-5p已知调节肿瘤支持性M2巨噬细胞的分化，但这些细胞在小儿ALK阳性ALCL中的作用尚不清楚。为了阐明miR-146a-5p和M2巨噬细胞在小儿ALCL疾病中的作用，使用ALK+ ALCL细胞系的s-EVs处理THP-1源的巨噬细胞，显示miR-146a-5p的内源性表达增加，迁移能力和M2标记物CD163和Arginase-1的上调。反过来，来自M2巨噬细胞或miR-146a-5p转染的THP-1的条件培养基增加了ALCL细胞的侵袭性特征，并富含白细胞介素-8。总体而言，这些数据表明miR-146a-5p在促进ALCL中的巨噬细胞浸润和M2样极化中起到了作用。我们的发现进一步促使我们对M2巨噬细胞在ALCL的侵袭性和扩散中的作用进行调查，同时考虑针对肿瘤相关巨噬细胞的新治疗选择。版权所有©2023年 Elsevier Inc. 发布。

Anaplastic large cell lymphoma (ALCL) is a CD30-positive lymphoma accounting for 20% of all pediatric T-cell lymphomas. Current first line treatment can cure most of ALCL patients but 10-30% of them are resistant or relapse. In this context, liquid biopsy has the potential to help clinicians in disease screening and treatment response monitoring. Small-RNA-sequencing analysis performed on plasma small-extracellular vesicles (s-EVs) from 20 pediatric anaplastic lymphoma kinase positive (ALK+) ALCL patients at diagnosis revealed a specific miRNAs cargo in relapsed patients compared to non-relapsed, with seven miRNAs enriched in s-EVs of relapsed patients. MiR-146a-5p and miR-378a-3p showed a negative prognostic impact both in univariate and multivariate analysis, possibly representing, together with let-7g-5p, a miRNA panel for the early identification of high-risk patients. Among them, miR-146a-5p is known to modulate tumor supporting-M2 macrophages differentiation, but the role of these cells in pediatric ALK+ALCL is still unknown. To elucidate the role of miR-146a-5p and M2 macrophages in pediatric ALCL disease, THP-1-derived macrophages were treated with s-EVs from ALK+ALCL cell lines, showing increased miR-146a-5p intracellular expression, migrating capability and M2-markers CD163 and Arginase-1 upregulation. In turn, conditioned media from M2 macrophages or miR-146a-5p-transfected THP-1 increased ALCL cells' aggressive features and were enriched in interleukin-8. Overall, these data suggest a role of miR-146a-5p in promoting macrophage infiltration and M2-like polarization in ALCL. Our findings incite further investigation on the role of M2 macrophages in ALCL aggressiveness and dissemination, also considering the novel treatment options targeting tumor associated macrophages.Copyright © 2023. Published by Elsevier Inc.