Guba S C, Sartor C A, Hutchinson R, Boxer L A, Emerson S G
Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock.
Blood. 1994 Mar 15;83(6):1486-92.
Congenital neutropenia (Kostmann's syndrome [KS]) is an autosomal recessive syndrome that is characterized by profound neutropenia, resulting in major clinical infections and death. Since the neutropenia and symptoms in KS improve in response to exogenous administration of granulocyte colony-stimulating factor (G-CSF), we studied bone marrow cytokine (G-CSF, granulocyte-macrophage CSF [GM-CSF], and interleukin-6) production under both basal and stimulated conditions. No differences in G-CSF, GM-CSF, or IL-6 gene expression were found in bone marrow stromal cells between normal controls and KS patients, and all three cytokines were detected by enzyme-linked immunosorbent assay (ELISA) in medium conditioned by bone marrow stromal cells from normal donors and patients with KS. Each KS patient tested had detectable, functional G-CSF in their own serum before exogenous G-CSF administration. Since G-CSF production appeared normal in KS patients, we then asked whether we could detect structural defects in the signaling portion of G-CSF receptor genes. Polymerase chain reaction (PCR) amplification of the G-CSF receptor transmembrane region alone, and of the transmembrane plus cytosolic portions of the receptor, yielded the size products predicted from the sequences of the normal G-CSF receptor. Single-strand conformational polymorphism (SSCP) analysis of G-CSF receptor PCR products demonstrated no variance in structural conformation between KS patients and normal subjects. These results demonstrate that bone marrow stromal cells in patients with KS secrete normal concentrations of functional G-CSF and suggest that the neutropenia in KS patients is caused by an inability of neutrophilic progenitor and precursor cells to respond to normal, physiologic levels of G-CSF. Such a defect, clinically responsive to pharmacologic doses of G-CSF, might be caused by defects in the post-G-CSF receptor signal transduction pathway.
先天性中性粒细胞减少症（科斯特曼综合征[KS]）是一种常染色体隐性综合征，其特征为严重的中性粒细胞减少，可导致严重的临床感染和死亡。由于KS患者的中性粒细胞减少症和症状在给予外源性粒细胞集落刺激因子（G-CSF）后会有所改善，我们研究了基础状态和刺激状态下骨髓细胞因子（G-CSF、粒细胞-巨噬细胞集落刺激因子[GM-CSF]和白细胞介素-6）的产生情况。正常对照和KS患者的骨髓基质细胞中，G-CSF、GM-CSF或白细胞介素-6基因表达没有差异，并且通过酶联免疫吸附测定（ELISA）在来自正常供体和KS患者的骨髓基质细胞培养的培养基中均检测到了这三种细胞因子。在给予外源性G-CSF之前，每个接受检测的KS患者自身血清中均可检测到可发挥功能的G-CSF。由于KS患者的G-CSF产生似乎正常，我们接着探究是否能在G-CSF受体基因的信号传导部分检测到结构缺陷。单独对G-CSF受体跨膜区域以及受体的跨膜加胞质部分进行聚合酶链反应（PCR）扩增，得到了与正常G-CSF受体序列预测大小相符的产物。对G-CSF受体PCR产物进行单链构象多态性（SSCP）分析表明，KS患者和正常受试者之间的结构构象没有差异。这些结果表明，KS患者的骨髓基质细胞分泌正常浓度的具有功能的G-CSF，并提示KS患者的中性粒细胞减少症是由于嗜中性祖细胞和前体细胞无法对正常生理水平的G-CSF作出反应所致。这种对药理剂量G-CSF有临床反应的缺陷可能是由G-CSF受体后信号转导途径中的缺陷引起的。
