A Novel CEBPE Variant Causes Severe Infections and Profound Neutropenia
A Novel CEBPE Variant Causes Severe Infections and Profound Neutropenia
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DOI：
10.1007/s10875-022-01304-7
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发表时间：
2022-06-20
影响因子：
9.1
通讯作者：
Singh，Surjit
中科院分区：
文献类型：
--
作者：
Banday，Aaqib Zaffar;Kaur，Anit;Singh，Surjit
目的特异性颗粒缺陷症（specific granule deficiency，SGD）是由编码转录因子C/EBPε的CEBPE基因的功能缺失变异引起的一种罕见的先天性免疫缺陷。虽然这种遗传病因学已被发现超过20年，只有少数患者CEBPE变异证实的SGD（I型）已被报道。在此，我们描述了两个兄弟姐妹与一个新的homohamorousCEBPE缺失谁被指出有深刻的中性粒细胞减少症的初步评估。我们的目的是评估这种新的变体，包括深刻的中性粒细胞减少症的免疫血液学后果。MethodsLight散射特性的粒细胞进行了检查各种自动血液分析仪。使用流式细胞术评估吞噬细胞免疫表型、活性氧生成和Toll样受体（TLR）信号传导。用RT-PCR方法研究了不同颗粒蛋白基因的相对表达量。采用免疫印迹法和荧光素酶报告基因分析方法，研究了C/EBPε变异体的表达和功能。粒细胞光散点图分析显示，由于中性粒细胞形态异常，自动血液分析仪可提供异常低的中性粒细胞计数。中性粒细胞显示CD 15/CD 16表达缺失/显著降低和CD 14/CD 64过表达（在一个亚组中）。三个不同的群体的吞噬细胞具有不同的氧化酶活性进行观察。在用TLR-4、TLR-2/6和TLR-7/8激动剂刺激时观察到CD 62配体脱落受损。结论CEBPE中c.655_665del纯合突变体可引起SGD。在I型SGD患者中可能报告异常的自动中性粒细胞计数。TLR信号异常可能是I型SGD免疫缺陷的另一个发病机制。
PurposeSpecific granule deficiency (SGD) is a rare inborn error of immunity resulting from loss-of-function variants inCEBPEgene (encoding for transcription factor C/EBPε). Although this genetic etiology has been known for over two decades, only a few patients withCEBPEvariant-proven SGD (type I) have been reported. Herein, we describe two siblings with a novel homozygousCEBPEdeletion who were noted to have profound neutropenia on initial evaluation. We aimed to evaluate the immunohematological consequences of this novel variant, including profound neutropenia.MethodsLight scatter characteristics of granulocytes were examined on various automated hematology analyzers. Phagocyte immunophenotype, reactive oxygen species generation, and Toll-like receptor (TLR) signaling were assessed using flow cytometry. Relative expression of genes encoding various granule proteins was studied using RT-PCR. Western blot analysis and luciferase reporter assay were performed to explore variant C/EBPε expression and function.ResultsSevere infections occurred in both siblings. Analysis of granulocyte light scatter plots revealed automated hematology analyzers can provide anomalously low neutrophil counts due to abnormal neutrophil morphology. Neutrophils displayed absence/marked reduction of CD15/CD16 expression and overexpression (in a subset) of CD14/CD64. Three distinct populations of phagocytes with different oxidase activities were observed. Impaired shedding of CD62-ligand was noted on stimulation with TLR-4, TLR-2/6, and TLR-7/8 agonists. We demonstrated the variant C/EBPε to be functionally deficient.ConclusionHomozygous c.655_665del variant inCEBPEcauses SGD. Anomalous automated neutrophil counts may be reported in patients with SGD type I. Aberrant TLR signaling might be an additional pathogenetic mechanism underlying immunodeficiency in SGD type I.