Pathogenesis And Treatment Of Aplastic Anemia

再生障碍性贫血的发病机制和治疗

• 批准号: 7594394
• 负责人: Neal S Young
• 金额: $ 449.96万
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 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/7594394
• 关键词: Acute Myelocytic Leukemia; Androgen Antagonists; Androgen Receptor; Androgens; Anemia; Aneuploidy; Annual Reports; Antigens; Antithymoglobulin; Aplastic Anemia; Autoimmune Process; Basic Science; Bone Marrow; CD34 gene; CD36 gene; CD4 Positive T Lymphocytes; Cancer Center; Capsid; Cause of Death; Cell Culture System; Cells; Cellular biology; Chemicals; Child; Chromosomes; Clinic; Clinical; Confocal Microscopy; Consent; Cultured Cells; Cyclosporine; Cyclosporins; Cytokine Gene; Data; Defective spinal cord development; Disease; Distant; Dose; Dysmyelopoietic Syndromes; End Point; Equus caballus; Estrogen Antagonists; Estrogens; Etiology; Evolution; Family member; Fathers; Female; Fibrosis; Functional disorder; Gene Expression; Genetic; Genetic Transcription; Genomic Instability; Genomics; Goals; Hematological Disease; Hematopoietic; Hemolysis; Hepatic; Hormones; Human; Human Parvovirus B19; Human Volunteers; Immune; Immune system; Immunosuppression; Immunosuppressive Agents; In Vitro; Infection; Inflammation; Interferon Type II; Investigation; Laboratories; Laboratory Study; Liver diseases; Malignant - descriptor; Marketing; Measures; Mediating; Medical; Mennonite; Methodology; Methods; Modeling; Molecular; Monoclonal Antibodies; Mus; Mutation; Myeloproliferative disease; Numbers; Oryctolagus cuniculus; Pancytopenia; Parvovirus; Pathogenesis; Patients; Pharmaceutical Preparations; Phase I Clinical Trials; Phase III Clinical Trials; Population; Procedures; Production; Protocols documentation; Randomized; Rate; Recombinants; Refractory anemias; Relapse; Relative (related person); Role; Sampling; Sickle Cell Anemia; Signal Transduction; Staging; Standards of Weights and Measures; Symptoms; Syndrome; T-Lymphocyte; TERT gene; Telomerase; Telomere Shortening; Testing; Therapeutic immunosuppression; Thrombosis; Tissues; Treatment Protocols; Tumor Antigens; United States Food and Drug Administration; Upper arm; Ursidae Family; Vaccines; Viral Genes; Virus; Work; cytokine; erythroid differentiation; improved; kindred; leukemia; liver transplantation; loss of function; male; neutralizing antibody; novel; prevent; proband; rat Piga protein; receptor; repaired; response; telomere; virology

This years annual report incorporates both the work of the Cell Biology Section in bone marrow failure diseases and also of the Virus Discovery Section in parvoviruses, as the latter has been incorporated into the former due to the departure of Dr. Kevin Brown. Aplastic anemia (AA) and other types of bone marrow failure have clinical and laboratory features consistent with an autoimmune pathophysiology, with a diversity of putative inciting antigens, including viruses, chemicals, medical drugs, and tumor antigens. Whatever its specific etiology, a majority of patients respond with hematologic improvement after immunosuppressive therapies. One important clinical feature of AA is its association with clonal hematologic diseases, especially paroxysmal nocturnal hemoglobinuria (PNH) and myelodysplastic syndromes (MDS). In the clinic, studies have been directed towards more effective immunosuppression in AA and the application of immunosuppressive regimens to related bone marrow failure syndromes. Multiple studies are in progress. While we observed some responses in first presentation aplastic anemia to the monoclonal antibody CAMPATH, this arm of our three-arm randomized protocol was discontinued early when it became clear that anti-CD52 was unlikely to be as effective as standard therapy. A comparison of horse and rabbitt ATG continues in this patient population. In AA refractory to standard horse ATG plus cyclosporine, both rabbit ATG and CAMPATH show activity about 30% salvage rate. We are also testing CAMPATH in the treatment of relapsed AA and in MDS. Our participation in a mulit-center trial of eculuzimab was completed; in addition to leading to FDA approval for this agent, now marketed as Soliris, for the indications of symptoms and/or severe anemia due to intravassular hemolysis in PNH, further analysis of end points has shown that the monoclonal antibody is also strikingly effective in reducing the rate of thrombosis, the major cause of death in PNH. In the laboratory, studies of immune destruction of hematopoietic cells has continued in several directions. We have examined the mechanism of action of the ATGs, especially as horse and rabbit products do not appear to be equally effective in the treatment of aplastic anemia. In cell culture and molecular studies, we have confirmed that rabbit ATG in vitro induces T-regulatory cells from CD25-FoxP3-CD4 cells while horse ATG lacks this activity. In order to study T-cells intensively, lymphocytopheresis in now being performed in patients who consent to this procedure prior to therapy and at the completion of a six month course in order to perform molecular studies of cytokine gene expression. Preliminary data suggests that T-cell clones that persist in patients who have fully recovered hematopoietic capacity lack production of gamma-interferon and other type-1 cytokines and therefore may be tolerant. In studies of the genetics of acquired AA with a focus of telomere repair, we have extended our findings from a large mennonite kindred bearing a novel TERT mutation, which disclosed a relationship to both acute myeloid leukemia in the proband's father and to severe hepatic disease in the proband's aunt and two more distant female relatives all of whom bear the mutation. In two separate cohert studies, one of 100 Brazilian patients with AML and the other of 92 patients collected at MD Anderson Cancer Center, we found a rate of approximately 6% of TERT mutations in this leukemia. In vitro studies have suggested that these are loss of function alterations; germline inheritance by study of non-bone marrow tissues and of family members. Similarly, preliminary data among samples collected of patients who have undergone liver transplant have also show several with TERT mutations. These results implicate telomere repair in the initiation of leukemia and also in severe liver disease, characterized at this point as a combinnation of fibrosis and inflammation. In our studies of the mechanism of action of male hormones in hematologic disease, we have demonstrated in vitro that synthetic and natural androgens and also estrodiol increase transcription of the TERT gene and of telomerase activity. The inhibitory activity of tamoxofin and of both anti-estrogen and anti-androgen receptor agents indicates that both aromatization of androgens to estrodiol and the estrogen and androgen receptors are involved in this effect on hematopoietic cells. We are pursuing our hypothesis that telomere shortening results in aneuploidy due to chromosome fusion and genomic instability, as has been demonstrated in murine models. In studies from the Virus Discovery Group related to parvoviruses, there have been a number of signal advances. First, a recombinant B19 parvovirus vaccine is now in its second phase 1 trial among human volunteers to determine the appropriate dose of empty capsids needed to elicit neutralizing antibodies, prior to a planned phase III trial in children with sickle cell disease with the goal of preventing transient aplastic crisis. Second, we have developed a practical infectious clone of B19 parvovirus, which has been useful to define by molecular studies and confocal microscopy the role of specific viral genes in infection of human cells. Finally, we have utilized our ability to obtain CD34 cells in bulk and to induce erythroid differentiation to develop a highly productive cell culture system for B19 parvovirus. CD34 cell-derived CD36 cells recapitulate normal erythropoeisis, including expression of the glogoside receptor, and they are useful also as a much more sensitive method to measure neutralizing antibodies, of use in our vaccine trials, and for molecular and cell biology studies of virus interaction with its known pathogenic target cell.

今年的年度报告既包含了细胞生物学部分在骨髓衰竭疾病方面的工作，也包含了病毒发现部分在细小病毒方面的工作，由于凯文·布朗博士的离开，后者已并入前者。 再生障碍性贫血（AA）和其他类型的骨髓衰竭具有与自身免疫病理生理学一致的临床和实验室特征，具有多种假定的刺激抗原，包括病毒、化学物质、药物和肿瘤抗原。无论其具体病因是什么，大多数患者在免疫抑制治疗后都会出现血液学改善的情况。 AA 的一项重要临床特征是其与克隆性血液疾病的相关性，尤其是阵发性睡眠性血红蛋白尿 (PNH) 和骨髓增生异常综合征 (MDS)。在临床上，研究主要针对 AA 更有效的免疫抑制以及免疫抑制方案在相关骨髓衰竭综合征中的应用。 多项研究正在进行中。 虽然我们在首次出现再生障碍性贫血时观察到单克隆抗体 CAMPATH 的一些反应，但当我们清楚抗 CD52 不太可能像标准疗法一样有效时，我们的三臂随机方案中的这一臂就提前终止了。 在该患者群体中继续对马和兔子 ATG 进行比较。 在对标准马 ATG 加环孢素耐药的 AA 中，兔 ATG 和 CAMPATH 均显示出约 30% 挽救率的活性。 我们还在测试 CAMPATH 治疗复发性 AA 和 MDS 的效果。 我们参与的 eculuzimab 多中心试验已完成；除了获得 FDA 批准该药物（目前以 Soliris 上市）用于治疗 PNH 血管内溶血引起的症状和/或严重贫血外，对终点的进一步分析表明，该单克隆抗体在降低血栓形成率方面也非常有效，血栓形成是 PNH 的主要死亡原因。 在实验室中，造血细胞免疫破坏的研究一直在几个方向上继续进行。 我们已经研究了 ATG 的作用机制，特别是因为马和兔产品在治疗再生障碍性贫血方面似乎并不同样有效。 在细胞培养和分子研究中，我们已经证实兔ATG在体外可以从CD25-FoxP3-CD4细胞诱导T调节细胞，而马ATG缺乏这种活性。 为了深入研究 T 细胞，现在在治疗前和完成六个月疗程后同意的患者中进行淋巴细胞分离术，以便进行细胞因子基因表达的分子研究。 初步数据表明，造血能力完全恢复的患者体内持续存在的T细胞克隆缺乏γ-干扰素和其他1型细胞因子的产生，因此可能具有耐受性。 在以端粒修复为重点的获得性 AA 遗传学研究中，我们将我们的发现扩展到了一个携带新型 TERT 突变的大型门诺家族，该突变揭示了与先证者父亲的急性髓性白血病以及先证者的姨妈和两个更远的女性亲属的严重肝病的关系，他们都携带该突变。在两项独立的一致性研究中，其中一名是 100 名巴西 AML 患者，另一名是 MD 安德森癌症中心收集的 92 名患者，我们发现这种白血病的 TERT 突变率约为 6%。 体外研究表明这些是功能丧失的改变；通过研究非骨髓组织和家庭成员进行种系遗传。 同样，从接受过肝移植的患者样本中收集的初步数据也显示一些患者存在 TERT 突变。 这些结果表明端粒修复与白血病的发生以及严重的肝病有关，此时的特征是纤维化和炎症的结合。 在我们对雄性激素在血液疾病中的作用机制的研究中，我们在体外证明了合成和天然雄激素以及雌二醇可增加 TERT 基因和端粒酶活性的转录。 他莫索芬以及抗雌激素和抗雄激素受体药物的抑制活性表明，雄激素芳香化为雌二醇以及雌激素和雄激素受体都参与了对造血细胞的这种作用。 我们正在追求我们的假设，即由于染色体融合和基因组不稳定，端粒缩短导致非整倍性，正如小鼠模型所证明的那样。 病毒发现小组有关细小病毒的研究取得了许多进展。 首先，重组 B19 细小病毒疫苗目前正在人类志愿者中进行第二期 1 期试验，以确定引发中和抗体所需的空衣壳的适当剂量，然后再计划对镰状细胞病儿童进行 III 期试验，以预防短暂的再生障碍性危机。 其次，我们开发了 B19 细小病毒的实用感染性克隆，它有助于通过分子研究和共聚焦显微镜确定特定病毒基因在人类细胞感染中的作用。 最后，我们利用大量获得 CD34+ 细胞并诱导红细胞分化的能力，开发了 B19 细小病毒的高产细胞培养系统。 CD34+细胞衍生的CD36+细胞再现了正常的红细胞生成，包括糖苷受体的表达，它们也可作为一种更灵敏的方法来测量中和抗体，用于我们的疫苗试验，以及病毒与其已知致病靶细胞相互作用的分子和细胞生物学研究。