Fattizzo Bruno, Da Vià Matteo Claudio, Lazzaroni Francesca, Marchetti Alfredo, Marella Alessio, Maeda Akihiro, Solimando Antonio Giovanni, Pettine Loredana, Passamonti Francesco, Bolli Niccolò, Barcellini Wilma
Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
Department of Oncology and Haemato-Oncology, University of Milan, Milan, Italy.
Signal Transduct Target Ther. 2025 Aug 25;10(1):277. doi: 10.1038/s41392-025-02348-y.
The role of bone marrow (BM) compensatory response in autoimmune hemolytic anemias (AIHAs) is emerging and inadequate reticulocytosis has been associated with more severe disease and adverse outcomes. However, few is known about the BM immunologic microenvironment composition in these diseases. Here we investigated BM features in a large cohort of 97 patients with autoimmune hemolytic anemia (AIHA) and observed a high prevalence of hypercellularity, dyserythropoiesis, reticulin fibrosis, and T-cell infiltration (65%, 29%, 76%, and 69% of patients, respectively). These findings were associated with inadequate bone marrow compensation, more severe anemia at onset, and need of multiple treatments. In a subset of warm type AIHA patients we investigated BM microenvironment by single-cell RNA sequencing. We found distinct immune cell profiles across disease stages (diagnosis, remission, relapse). In particular, upregulation of inflammatory response pathways was noted in CD8 + , CD4 + , and monocyte subsets during relapse compared to diagnosis and remission. Moreover, by single-cell TCR sequencing, we found small T cell clones at diagnosis that may either disappeared or expanded at remission. Disappearing clones exhibited a naive CD8+ phenotype and were more likely to respond to glucocorticoid treatment. Expanding clones showed upregulation of cytotoxic T cell markers and may play a role in the transition to a chronic/relapsing phase. Finally, cytokine gene expression differed across disease phases. At relapse, pro-inflammatory cytokines such as TNF-alpha, IL-1, and IL-6 were upregulated in CD4+ and CD8 + T cells, while TGF-beta was downregulated, potentially in an attempt to counteract the transition to chronic phase. This is the largest study evaluating BM histology and clinical characteristics, and the first evaluation of BM microenvironment by single-cell RNA sequencing in AIHA. We showed a complex scenario encompassing T-cell infiltration, clonality, and up/down-regulation of cytokine genes, associated with a more severe and relapsing disease.
骨髓（BM）代偿反应在自身免疫性溶血性贫血（AIHA）中的作用正在显现，网织红细胞生成不足与更严重的疾病及不良预后相关。然而，对于这些疾病中骨髓免疫微环境的组成知之甚少。在此，我们调查了97例自身免疫性溶血性贫血（AIHA）患者的大样本队列中的骨髓特征，观察到细胞增多、红细胞生成异常、网状纤维纤维化和T细胞浸润的高发生率（分别占患者的65%、29%、76%和69%）。这些发现与骨髓代偿不足、发病时更严重的贫血以及需要多种治疗有关。在一部分温抗体型AIHA患者中，我们通过单细胞RNA测序研究了骨髓微环境。我们发现不同疾病阶段（诊断、缓解、复发）有不同的免疫细胞谱。特别是，与诊断和缓解期相比，复发期CD8 +、CD4 +和单核细胞亚群中炎症反应途径上调。此外，通过单细胞TCR测序，我们发现在诊断时存在小的T细胞克隆，这些克隆在缓解期可能消失或扩增。消失的克隆表现出幼稚CD8 +表型，更可能对糖皮质激素治疗有反应。扩增的克隆显示细胞毒性T细胞标志物上调，可能在向慢性/复发期转变中起作用。最后，细胞因子基因表达在不同疾病阶段有所不同。在复发期，促炎细胞因子如TNF-α、IL-1和IL-6在CD4 +和CD8 + T细胞中上调，而TGF-β下调，这可能是为了试图抵消向慢性期的转变。这是评估骨髓组织学和临床特征的最大规模研究，也是首次通过单细胞RNA测序对AIHA患者的骨髓微环境进行评估。我们展示了一个复杂的情况，包括T细胞浸润、克隆性以及细胞因子基因的上调/下调，这与更严重和复发的疾病相关。
