Laboratory Assessment of Patients with Systemic Mastocytosis

系统性肥大细胞增多症患者的实验室评估

• 批准号: 7593139
• 负责人: irina maric
• 金额: $ 1.8万
• 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/7593139
• 关键词: Aspirate substance; Biological Assay; Bone Marrow; Bone marrow biopsy; C-KIT Gene; CD2 Antigens; CD25 Antigens; Chronic eosinophilic leukemia; Clinical; Collaborations; Confusion; Data; Data Set; Detection; Diagnosis; Diagnostic; Disease; Elements; Eosinophilia; Evaluation; Flow Cytometry; Gene Fusion; Hematopoietic; IL2RA gene; Imatinib; Immunophenotyping; Laboratories; Literature; Molecular; Mutation; Myeloproliferative disease; National Institute of Allergy and Infectious Disease; Neoplastic Mast Cell; Nomenclature; PDGFRA gene; Pathogenesis; Patients; Peripheral; Peripheral Blood Eosinophilia; Phosphotransferases; Point Mutation; Proto-Oncogenes; Receptor Activation; Receptor Protein-Tyrosine Kinases; Reporting; Risk Factors; Score; Selection for Treatments; Somatic Mutation; Stem Cell Factor; Syndrome; System; Systemic Mastocytosis; Testing; body system; eosinophil; fusion gene; inhibitor/antagonist; mast cell; mastocytosis; novel diagnostics; outcome forecast; prognostic; response

Laboratory evaluation of patients with suspected systemic mastocytosis (SM) includes: (1) morphologic review of bone marrow biopsies and aspirates, (2) molecular testing for the presence of the KIT mutation and (3) immunophenotypic analysis of mast cells and other hematopoietic elements by flow cytometry. Recently, we have developed RT-PCR/RFLP assay for detection of the most prevalent KIT mutation in mastocytosis patients (D816V).The D816V mutation results in constitutive activation of the receptor tyrosine kinase and is believed to be involved in disease pathogenesis. We have also developed a flow cytometric assay for immunophenotypic analysis of mast cells, since it has been recently described that neoplastic mast cells display aberrant immunophenotype, most notably, aberrantly coexpress CD117 with CD25 and/or CD2. So far, the results of our analysis show complete concordance between diagnosis of systemic mastocytosis, the presence of KIT D816V point mutation, and aberrant expression of CD25 antigen on mast cells. Expression of CD2 antigen on mast cells is detected in 57% of patients with systemic mastocytosis. Aberrant expression of CD25 and CD2 is not detected in normal marrow mast cells. The identification of the KIT D816V mutation in patients with systemic mastocytosis has lately gained a major prognostic significance, largely because of the availability of tyrosine kinase receptor inhibitors such as imatinib. Imatinib was shown to be ineffective in patients carrying KIT D816V mutation, but effective in cases with some other mutations. Therefore, it is of paramount importance to correctly identify SM patients with KIT D816V mutation. Although most patients with SM do not have peripheral blood eosinophilia, both bone marrow and peripheral blood eosinophilia have been reported in D816V mutation-positive patients. In these cases, the broad and overlapping clinical manifestations between the patients with D816V KIT-associated systemic mastocytosis with eosinophilia and patients with chronic eosinophilic leukemia (CEL) associated with FIP1L1/PDGFRA fusion gene present diagnostic challenge. The increase in activated eosinophils and mast cells is seen in both disorders, and has led to confusion in the nomenclature. It is of paramount importance, however, to distinguish between these two groups of patients because of differences in clinical sequelae, prognoses and selection of treatment. This has profound consequences for patients with these disorders, since the FIP1L1/PDGFRA and D816V mutations respond dramatically differently to therapy. Most notably, the FIP1L1/PDGFRA fusion kinase, but not D816V KIT mutation, is inhibited by imatinib. We thus sought to identify clinical and laboratory features that could be used to distinguish these two diagnoses. We compared 12 patients with D816V-positive systemic mastocytosis with eosinophilia with 17 patients with FIP1L1/PDGFRA-positive CEL. Distinguishing features were used to create a risk factor scoring system. This system correctly classified 16/17 FIP1L1/PDGFRA-positive CEL patients, and all 12 systemic mastocytosis with eosinophilia patients. Thirty-four FIP1L1/PDGFRA-positive patients described in the literature were also classified using this system, and although a complete set of data was not available for any of the historical patients, 21 were correctly classified. These results reinforce the hypothesis that the FIP1L1/PDGFRA gene fusion and D816V-KIT mutation cause distinct clinical syndromes. This novel diagnostic approach should prove helpful in clinical practice in the evaluation of patients with increased mast cells burden and peripheral eosinophilia.

实验室评估可疑的全身肥大症患者（SM）包括：（1）对骨髓活检和抽吸物的形态学综述，（2）通过流式细胞术对肥大细胞和其他造血元素对KIT突变的存在以及（3）分子检测。最近，我们开发了RT-PCR/RFLP测定法，用于检测肥大细胞增多症患者中最普遍的试剂盒突变（D816V）。D816V突变导致受体酪氨酸激酶的组成型激活，并被认为与疾病发病发作有关。我们还开发了一种用于对肥大细胞的免疫表型分析的流式细胞仪测定，因为最近已经描述了肿瘤肥大细胞显示出异常的免疫表型，最值得注意的是，与CD25和/或CD2异常共表达CD117。到目前为止，我们的分析结果表明，全身肥大症的诊断，KIT D816V点突变的存在与肥大细胞上CD25抗原的异常表达之间的一致性。在57％的全身性肥大性患者中，检测到CD2抗原在肥大细胞上的表达。在正常骨髓肥大细胞中未检测到CD25和CD2的异常表达。 最近，全身性肥大症患者的试剂盒D816V突变的鉴定已获得了主要的预后意义，这主要是因为酪氨酸激酶受体抑制剂（如伊马替尼）的可用性。伊马替尼在携带KIT D816V突变的患者中无效，但在其他一些突变的情况下有效。因此，正确识别具有KIT D816V突变的SM患者至关重要。尽管大多数SM患者没有外周血嗜酸性粒细胞，但在D816V突变阳性患者中，骨髓和外周血嗜酸性粒细胞均已报道。在这些情况下，与嗜酸性粒细胞增多的D816V试剂盒相关的全身性肥大症与慢性嗜酸性白血病（CEL）患者与FIP1L1/PDGFRA融合基因相关的慢性嗜酸性白血病（CEL）患者之间的广泛而重叠的临床表现。在两种疾病中都可以看到活化的嗜酸性粒细胞和肥大细胞的增加，并导致命名法的混乱。然而，由于临床后遗症，预后和治疗选择的差异，区分这两组患者至关重要。由于FIP1L1/PDGFRA和D816V突变对治疗的反应很大，因此这对这些疾病患者产生了深远的影响。 最值得注意的是，伊马替尼抑制了FIP1L1/PDGFRA融合激酶，而不是D816V试剂盒突变。 因此，我们试图确定可用于区分这两个诊断的临床和实验室特征。我们与17例FIP1L1/PDGFRA阳性CEL的患者进行了比较了12例D816V阳性全身性肥大性肥大性肥大症患者。区分功能用于创建风险因素评分系统。该系统正确地将16/17 FIP1L1/PDGFRA阳性CEL患者和嗜酸性粒细胞增生的所有全身性肥大性分类。 文献中描述的34例FIP1L1/PDGFRA阳性患者也使用该系统进行了分类，尽管任何历史患者都无法使用完整的数据集，但正确分类了21名。这些结果加强了以下假设：FIP1L1/PDGFRA基因融合和D816V-KIT突变会导致不同的临床综合征。这种新型的诊断方法应证明对临床实践有所帮助，以评估肥大细胞负担和周围嗜酸性粒细胞增长的患者。