Identification of biomarker(s) of monocyte precursors in human bone marrow

单核细胞起源于骨髓，并通过血液传播到组织，在那里它们成为巨噬细胞或树突状细胞。由于慢性感染、自身免疫性疾病以及某些急性和慢性白血病，血液中单核细胞增多(单核细胞增多症)。在白血病中，有多种类型，包括急性单核细胞白血病、急性单核细胞白血病、急性单核细胞白血病和慢性单核细胞白血病。其他术语，如单核细胞分化的急性髓系白血病，也被使用，增加了本已令人困惑的命名法。目前，用于单核细胞谱系鉴定的主要技术有细胞形态学、细胞化学和流式细胞术，但对各种类型的急、慢性白血病及其与良性单核细胞增多症的鉴别仍然是一个严峻的挑战。这在很大程度上是因为对原始、发育异常或反应性单核细胞的识别远远不准确或精确。基因突变常见于单核细胞白血病，但也不是特异性的，因为它们在其他肿瘤过程中也能观察到。这种不确定性转化为严肃的诊断甚至治疗决定，这些决定通常基于确定单核细胞增殖的性质，或准确的原始细胞计数。大多数非单核细胞急性白血病(髓系或淋巴系)重现早期正常前体的表型，因此表达高信息量的抗原，如CD34、CD117或TDT。这些白血病相关抗原不是肿瘤细胞所特有的。它们只是在骨髓中正常细胞发育的早期阶段表达的抗原。在单核细胞发育的早期阶段表达的标志物很可能也可以作为单核细胞白血病的原始细胞的适当识别符。然而，与粒细胞性或淋巴细胞性白血病不同，没有单一的标志物可以明确识别白血病单核细胞。这在很大程度上是因为人类单核细胞前体还没有得到充分的表征。在初步观察的基础上，我们建议使用流式细胞术和分选技术从正常人骨髓中鉴定和纯化假定的单核细胞前体：1.证明它们确实是单核细胞前体；2.使用RNAseq技术将它们的转录组与骨髓中所有其他细胞的转录组进行比较，以确定能够鉴定它们的特定RNA标记(以及最终产物)。对单核细胞前体细胞(以及可能的单核细胞母细胞)的适当认识应该能够帮助我们建立更好的单核细胞白血病的诊断和分类，并帮助设计适当的治疗分层。

Monocytes originate in the bone marrow, and travel through the blood to tissues where they become macrophages or dendritic cells. An increased number of monocytes in the blood (monocytosis) occurs in response to chronic infections, autoimmune disorders, and in certain acute and chronic leukemias. Among the leukemias, various types have been recognized, including acute myelomonocytic, acute monoblastic, acute monocytic, and chronic myelomonocytic leukemia. Other terms, such as acute myeloid leukemia with monocytic differentiation, are also used, adding to the already confusing nomenclature. At present, the main techniques utilized in the identification of monocytic lineage are cytomorphology, cytochemistry and flow cytometry, but the exact delineation of the various types of acute and chronic leukemias and their differentiation from benign monocytosis has remained a serious challenge. This is largely because the identification of blastic, dysplastic or reactive monocytes is far from being accurate or precise. Genetic mutations are often observed in monocytic leukemias but again, they are not specific since they are observed in other neoplastic processes. This uncertainty translates into serious diagnostic or even therapeutic decisions, which are often based on determining the nature of a monocytic proliferation, or an accurate blast count. Most non-monocytic acute leukemias (myeloid or lymphoid) recapitulate the phenotype of early normal precursors and thus express highly informative antigens like CD34, CD117, or TdT. These leukemic-associated antigens are not specific for the neoplastic cells. They are simply antigens that are expressed in early stages of normal cell development in the marrow. It is very likely that markers expressed in early stages of monocyte development could as well serve as proper identifiers for blasts in monocytic leukemias. However, in contrast to granulocytic or lymphoid leukemias, there are no single markers that allow the unequivocal recognition of leukemic monocytes. This is largely because human monocyte precursors have not been adequately characterized. Based on preliminary observations, we propose to identify and purify putative monocytic precursor from normal human bone marrow using flow cytometry/sorting and: 1. Demonstrate that they are indeed monocytic precursors and, 2. Compare their transcriptome with that of all other cells in the marrow using the RNAseq technique in order to identify specific RNA markers (and eventually products) that would allow their identification. Appropriate recognition of monocyte precursors (and likely monocytic blasts) should enable us to establish better diagnosis and classification of monocytic leukemias and help designing proper therapeutic stratification.