Laboratory Assessment of Patients with Hypereosinophilic Syndrome

嗜酸性粒细胞增多综合征患者的实验室评估

• 批准号: 8565378
• 负责人: Irina Maric
• 金额: --
• 依托单位: CLINICAL CENTER
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8565378
• 关键词: Basophils; Biological Assay; Blood specimen; Bone Marrow; Chromosome 4; Chronic eosinophilic leukemia; Clinical; Data; Diagnosis; Disease; Disseminated eosinophilic collagen disease; Endomyocardial Fibrosis; Enzyme-Linked Immunosorbent Assay; Eosinophilia; Equilibrium; Fibrosis; Flow Cytometry; Granulocyte-Macrophage Colony-Stimulating Factor; Human; IL3 Gene; IL5 gene; Idiopathic Hypereosinophilic Syndromes; Imatinib; Imatinib mesylate; In Vitro; Interleukin-5; Laboratories; Legal patent; Measures; Monitor; Monoclonal Antibody Therapy; Myelofibrosis; Myeloproliferative disease; National Institute of Allergy and Infectious Disease; Normal Range; PDGFRA gene; Patients; Peripheral Blood Eosinophilia; Peripheral Blood Mononuclear Cell; Production; Protein Tyrosine Kinase; Regulation; Regulatory Pathway; Reverse Transcriptase Polymerase Chain Reaction; Serum; Shapes; Subgroup; Surface; Systemic Mastocytosis; Testing; Time; Tissues; Tryptase; eosinophil; fusion gene; in vivo; interstitial; mast cell; mastocytosis; novel; outcome forecast; peripheral blood; receptor; response; treatment response; volunteer

A subset of patients presenting with hypereosinophilic syndrome (HES) have clinical features consistent with a myeloproliferative disorder. These patients have aggressive disease characterized by tissue fibrosis, including endomyocardial fibrosis and myelofibrosis and a poor prognosis. The peripheral blood mononuclear cells of these patients have an interstitial deletion in chromosome 4, leading to the formation of the imatinib-sensitive FIP1L1/PDGFRA fusion gene, thus fulfilling the WHO criteria for a diagnosis of chronic eosinophilic leukemia (CEL). We have established a novel RT-PCR assay to test for FIP1L1/PDGFRA fusion gene in peripheral blood samples of patents with eosinophilia. Positive patients are followed over time and treatment responses are monitored using this novel RT-PCR assay. However, the majority of patients with eosinophilia do not have FIP1L1/PDGFRA fusion gene and are classified as idiopathic HES. Very little is known about surface and soluble IL-5 receptor alpha expression in patients with eosinophilia. IL5 receptor alpha (IL-5Ra) is a surface receptor found on eosinophils, mast cells, basophils and their precursors. Although it has been clearly demonstrated that IL-5, IL-3 and GM-CSF down regulate surface expression of IL-5 receptor alpha (IL-5Ra) on normal eosinophils with a concomitant increase in production of the soluble form (sIL-5Ra), little is known about IL-5Ra regulation in patients with increased eosinophils (HES patients) or increased mast cells (mastocytosis patients). Surface expression of IL-5Ra on eosinophils and mast cells was assessed by flow cytometry. Soluble IL-5Ra levels were measured by capture ELISA in serum from patients with eosinophilia (n=11), D816KIT positive systemic mastocytosis (n=8) and normal volunteers (n=7). Results revealed that IL5-Ra expression had an inverse correlation with eosinophil levels in patients with eosinophilia (r=-0.85, p=0.0037), but not in normal controls. In contrast, serum sIL-5Ra was detectable in all 11 patients with eosinophilia, but in only 2 of 7 normal volunteers. Interestingly, serum sIL5Ra levels were comparable in the patients with eosinophilia (GM 957, range 214-15,450 ng/ml) and systemic mastocytosis (GM 847, range 355-1,805 ng/ml) despite eosinophil counts within the normal range in 4/8 mastocytosis patients. Basophil counts were also comparable between the two groups (GM 55 vs.32/mm3, respectively). These data are consistent with an in vivo IL-5R regulatory pathway in human eosinophils and mast cells similar to that described in vitro and involving a balance between surface and soluble receptor levels. This may have important implications in the face of recently developed monoclonal antibody therapies against IL-5 and its receptor.

出现嗜酸性粒细胞增多综合征（HES）的一部分患者具有与骨髓增生性疾病一致的临床特征。这些患者具有以组织纤维化为特征的侵袭性疾病，包括肌内膜纤维化和骨髓纤维化，并且预后差。这些患者的外周血单个核细胞在4号染色体上有间质缺失，导致伊马替尼敏感的FIP 1 L1/PDGFRA融合基因的形成，从而符合WHO诊断慢性嗜酸性粒细胞白血病（CEL）的标准。我们建立了一种新的RT-PCR方法检测FIP 1 L1/PDGFRA融合基因在嗜酸性粒细胞增多症患者外周血标本中的表达。随着时间的推移，对阳性患者进行随访，并使用这种新的RT-PCR测定法监测治疗反应。然而，大多数嗜酸性粒细胞增多症患者没有FIP 1 L1/PDGFRA融合基因，被归类为特发性HES。 关于嗜酸性粒细胞增多症患者的表面和可溶性IL-5受体α表达知之甚少。IL 5受体α（IL-5 Ra）是在嗜酸性粒细胞、肥大细胞、嗜碱性粒细胞及其前体上发现的表面受体。尽管已经清楚地证明IL-5、IL-3和GM-CSF下调正常嗜酸性粒细胞上IL-5受体α（IL-5 Ra）的表面表达，同时可溶性形式（sIL-5 Ra）的产生增加，但对嗜酸性粒细胞增加的患者（HES患者）或肥大细胞增加的患者（肥大细胞增多症患者）中IL-5 Ra的调节知之甚少。 通过流式细胞术评估IL-5 Ra在嗜酸性粒细胞和肥大细胞上的表面表达。 通过捕获ELISA测量嗜酸性粒细胞增多症患者（n=11）、D816 KIT阳性系统性肥大细胞增多症患者（n=8）和正常志愿者（n=7）血清中可溶性IL-5 Ra水平。结果显示，IL 5-Ra表达与嗜酸性粒细胞水平呈负相关（r=-0.85，p=0.0037），但在正常对照组中不存在。与此相反，血清sIL-5 Ra检测所有11例嗜酸性粒细胞增多症，但只有2 7正常志愿者。有趣的是，尽管4/8例肥大细胞增多症患者的嗜酸性粒细胞计数在正常范围内，但嗜酸性粒细胞增多症（GM 957，范围214- 15，450 ng/ml）和系统性肥大细胞增多症（GM 847，范围355- 1，805 ng/ml）患者的血清sIL 5 Ra水平相当。两组之间的嗜碱性粒细胞计数也相当（分别为GM 55 vs.32/mm 3）。 这些数据与人嗜酸性粒细胞和肥大细胞中的体内IL-5 R调节途径一致，其与体外描述的相似，并且涉及表面和可溶性受体水平之间的平衡。这可能对最近开发的针对IL-5及其受体的单克隆抗体疗法具有重要意义。