Abstract：
CD19 directed CAR T-cell therapy is used to treat relapsed/refractory B-cell acute lymphoblastic leukemia. The role of the pre-CAR bone marrow (BM) stromal microenvironment in determining response to CAR T-cell therapy has been understudied. We performed whole transcriptome analysis, reticulin fibrosis assessment and CD3 T-cell infiltration on BM core biopsies from pre- and post-CAR timepoints for 61 patients, as well as on a cohort of 54 primary B-ALL samples. Pathways of fibrosis, extracellular matrix development, and associated transcription factors AP1 and TGF-β3, were enriched and upregulated in nonresponders (NR) even prior to CAR T cell therapy. NR showed significantly higher levels of BM fibrosis compared to complete responders by both clinical reticulin assessment and AI-assisted digital image scoring. CD3+ T cells showed a trend toward lower infiltration in NR. NR had significantly higher levels of pre-CAR fibrosis compared to primary B-ALL. High levels of fibrosis were associated with lower overall survival after CAR T-cell therapy. In conclusion, BM fibrosis is a novel mechanism mediating nonresponse to CD19-directed CAR T-cell therapy in B-ALL. A widely used clinically assay for quantitating myelofibrosis can be repurposed to determine patients at high risk of non-response. Genes and pathways associated with BM fibrosis are a potential target to improve response.
摘要：
CD19指导的CART细胞疗法用于治疗复发性/难治性B细胞急性淋巴细胞白血病。前CAR骨髓（BM）基质微环境在确定对CART细胞疗法的反应中的作用已被充分研究。我们进行了全转录组分析,61例患者在CAR前后时间点的BM核心活检中的网状蛋白纤维化评估和CD3T细胞浸润，以及一组54个主要的B-ALL样本。纤维化的途径，细胞外基质发育，和相关转录因子AP1和TGF-β3在无反应者（NR）中富集和上调，甚至在CART细胞治疗之前。通过临床网状蛋白评估和AI辅助的数字图像评分,与完全应答者相比,NR显示出显著更高的BM纤维化水平。CD3+T细胞在NR中显示出较低的浸润趋势。与原发性B-ALL相比,NR具有显著更高水平的前CAR纤维化。高水平的纤维化与CAR-T细胞治疗后较低的总生存率相关。总之,BM纤维化是介导B-ALL中对CD19定向CAR-T细胞疗法无反应的新机制。用于定量骨髓纤维化的广泛使用的临床测定可用于确定处于无反应的高风险的患者。与BM纤维化相关的基因和途径是改善反应的潜在靶标。
