Immune Pathophysiology of Aplastic Anemia and Immunosuppressive Treatments

再生障碍性贫血的免疫病理生理学和免疫抑制治疗

• 批准号: 10685871
• 负责人: NEAL S YOUNG
• 金额: $ 489.58万
• 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/10685871
• 关键词: Adverse event; Age; Anemia; Animal Model; Animals; Antithymoglobulin; Aplastic Anemia; Apoptosis; Autoimmunity; Benzene; Biological Products; Blood; Bone Marrow; Bone Marrow Transplantation; Cell Therapy; Cell-Mediated Cytolysis; Cells; Cellularity; Cessation of life; Chemical Exposure; Clinical; Clinical Data; Clinical Protocols; Clinical Trials; Complex; Complication; Cyclosporine; Data; Deletion Mutation; Development; Diagnosis; Disease; Dose; Drug toxicity; Drug usage; Enrollment; Event; Evolution; Exposure to; Failure; Fatty acid glycerol esters; Functional disorder; Future; Hematology; Hematopoiesis; Hematopoietic; Hemorrhage; Hepatitis; Hospitalization; Human; Immune; Immune System Diseases; Immune response; Immune system; Immunologic Surveillance; Immunological Models; Immunosuppression; Immunosuppressive Agents; In complete remission; Infection; Infusion procedures; Ingestion; Innate Immune System; Interferon Type II; Laboratories; Laboratory Research; Laboratory Study; Link; Lymphocyte; Malignant - descriptor; Marrow; Mediating; Medical; Modeling; Molecular; Mus; Mutate; Myeloid-derived suppressor cells; Myeloproliferative disease; Oral; Outcome; Outpatients; Pancytopenia; Pathologic; Pathway interactions; Patients; Pattern; Pattern Recognition; Persons; Pharmaceutical Preparations; Physicians; Plasma; Play; Population; Pregnancy; Prevention trial; Protocols documentation; Publishing; Pure Red-Cell Aplasia; Recovery; Refractory; Regimen; Relapse; Reporting; Research; Residual state; Risk; Risk Factors; Role; Signal Pathway; Sirolimus; T cell response; T-Lymphocyte; TNF gene; Testing; Thrombopoietin; Time; Treatment Efficacy; Treatment Protocols; Visit; Work; base; bone marrow failure syndrome; cell injury; cell killing; chronic T-cell leukemia; clinical center; cohort; compliance behavior; conditioning; cytokine; cytotoxic; disorder later incidence prevention; effector T cell; experience; experimental study; falls; graft vs host disease; improved; inhibitor; interest; large datasets; lymph nodes; macrophage; mimetics; mouse model; pandemic disease; peripheral blood; prevent; receptor; response; sample collection; single-cell RNA sequencing; stem cells; therapeutic evaluation

In aplastic anemia, the bone marrow is replaced by fat, and peripheral blood fall to extremely low levels, leading to death from anemia, bleeding or infection. Aplastic anemia is a disease of mainly young persons and when severe is almost invariably fatal when untreated. Aplastic anemia has been linked to chemical exposures, in particular benzene; it is an idiosyncratic complication of some medical drug use; it occurs as a rare event in pregnancy and following seronegative hepatitis; and with immune system diseases, both autoimmunity and immunodefiency states. The serendipitous observation that some patients post-bone marrow transplant recovered their own marrow function led to the inference that the immunosuppressive conditioning regimen might have treated an underlying immune-mediated pathophysiology. Purposeful administration of anti-thymocyte globulin (ATG) has led to hematologic recovery in the majority of treated patients. Laboratory data have also revealed abnormalities of the immune system: lymphocyte populations that induce apoptosis in hematopoietic target cells by the Fas-mediated pathway, and oligoclones of effector T cells which express type 1 cytokines, especially gamma-interferon. More recently, eltrombopag, a thrombopoietin mimetic, was shown by us to be effective in improving clinical outcomes; data from our Branch were the basis for approval by the FDA for use of this drug in both refractory and treatment-nave severe aplastic anemia. Our section within the Hematology Branch has been a leader in both scientific research and medical studies of aplastic anemia pathophysiology and treatment. In clinical work, our protocol for severe, treatment-nave aplastic anemia was extended to collect more clinical data and subsequently for purposes of ancillary research laboratory studies, both aimed in particular at long-term outcomes. Our large cohort is of unique value in providing accurate estimates of response rates, relapse, and evolution to myeloid malignancies with now standard therapy. Overall and complete response rates are consistent with the initial report, and survival remains very high. There have been no significant changes in reported rates of relapse and malignant evolution. We have used both the triple therapy cohort to identify risk factors for later development of MDS and AML. Age remains the major risk factor, but additionally large datasets have allowed recognition of patterns of clonal hematopoiesis of significance. For one example, ASXL1 (but not DNMT3A) mutated clones increase the likelihood of evolution. Another example is the pattern of HLA and deletions and mutations within the HLA complex that suggest distinct modes of escape of malignant clones from immune surveillance. Sample collection for single cell work in the extension protocol already has yielded striking results. Cytotoxic lymphocytes in marrow are increased in AA and markedly reduced by triple therapy (but not eliminated); conversely, stem cells are absent on presentation and increase in responding patients. RNA sequencing of single cells shows concordant results, and changes in signaling pathways and clone size similar to our just published data in large granular lymphocytic leukemia. Of particular interest, expansion in the hematopoietic compartment occurs mainly among more committed mature stem cells. In a second clinical protocol for treatment-nave disease, we initiate low risk oral therapy, cyclosporine and eltrombobag, in order to introduce immunosuppression and stem cell stimulation early and to prevent loss of hematopoietic cells to T cell killing. Telemedicineespecially useful during the pandemic--has been employed to enroll and follow patients until they are admitted to the Clinical Center for definitive anti-thymocyte globulin infusion (if needed). Unexpected adverse events, especially drug toxicity, errors in diagnosis, and patient compliance to outpatient visits and physician directives have been excellent and the response rate as high or superior to the standard regimen. Our relapse prevention trial, assessing rapamycin (sirolimus) as a lymphocytotoxic tolerogenic agent continues to accrue. Study drug has been well tolerated. Our retrospective data indicate that future protocols, preferably multicenter, should test sirolimus at an earlier time point, around six months, when the cyclosporine dose is sharply reduced and eltrombopag discontinued. Our mouse model of immune marrow failure has continued to yield interesting and important data. Based on our finding of a role of macrophages and tumor necrosis factor in the pathologic immune response, experiments have been performed to test other components of the innate immune system. As reported previously, Toll receptors and a variety of cytokines do not appear to play roles in this model. However, myeloid suppressor cells are active in reducing the T cell response and ameliorating hematopoietic failure, Cell therapy has been used in graft-versus-host disease and may have utility in refractory immune marrow failure. We have extensively tested the therapeutic efficacy of a commercial Jak1/Jak2 inhibitor, ruxolitinib, in our murine models. This drug is ingested as a component of chow to mice. Ruxolitinib not only completely prevents marrow failure when administered prior to infusion of lymph node cells but is effective even days after infusion, in contrast to our previous experience with a variety of immunosuppressive agents. Survival is excellent after brief periods of exposure to drug with essentially normal blood counts and marrow cellularity long term, and only modest evidence of residual stem cell damage. Plasma cytokines remain normal and the expected signaling pathways are blocked by this jakinib. Drug toxicity in both treated animals in the model and in healthy animals is minimal. These results support a clinical trial of ruxolitinib in a variety of immune marrow diseases, relapsed and refractory AA as well as low risk MDS and pure red cell aplasia, and potentially as replacement for ATG, avoiding hospitalization and infusion risks from this incompletely defined biologic agent.

在再生障碍性贫血中，骨髓被脂肪取代，外周血降至极低水平，导致因贫血、出血或感染而死亡。再生障碍性贫血主要是年轻人的一种疾病，严重时如果不治疗几乎总是致命的。再生障碍性贫血与化学物质接触有关，特别是苯；它是某些药物使用的特殊并发症；它在怀孕期间和血清阴性肝炎后发生为罕见事件；以及免疫系统疾病，包括自身免疫和免疫缺陷状态。偶然观察到一些患者在骨髓移植后恢复了自己的骨髓功能，由此推断免疫抑制调理方案可能治疗了潜在的免疫介导的病理生理学。有目的地施用抗胸腺细胞球蛋白（ATG）已使大多数接受治疗的患者的血液学恢复。实验室数据还揭示了免疫系统的异常：通过Fas介导的途径诱导造血靶细胞凋亡的淋巴细胞群，以及表达1型细胞因子（尤其是γ-干扰素）的效应T细胞的寡克隆。最近，我们证明艾曲波帕（一种血小板生成素模拟物）可有效改善临床结果；我们分部的数据是 FDA 批准该药物用于治疗难治性和未经治疗的严重再生障碍性贫血的基础。我们血液科的部门在再生障碍性贫血病理生理学和治疗的科学研究和医学研究方面一直处于领先地位。 在临床工作中，我们对严重的、未经治疗的再生障碍性贫血的方案进行了扩展，以收集更多的临床数据，随后用于辅助研究实验室研究，两者都特别针对长期结果。我们的大型队列在提供对目前标准疗法的骨髓恶性肿瘤的反应率、复发和演变的准确估计方面具有独特的价值。总体和完全缓解率与最初的报告一致，存活率仍然很高。报告的复发率和恶性进化率没有显着变化。我们使用三联疗法队列来确定后期发展为 MDS 和 AML 的危险因素。年龄仍然是主要的风险因素，但此外，大型数据集已允许识别重要的克隆造血模式。例如，ASXL1（但不是 DNMT3A）突变克隆增加了进化的可能性。另一个例子是 HLA 模式以及 HLA 复合体内的缺失和突变，这表明恶性克隆逃避免疫监视的不同模式。扩展方案中单细胞工作的样本收集已经取得了惊人的结果。 AA 中骨髓中的细胞毒性淋巴细胞增加，三联疗法显着减少（但未消除）；相反，干细胞在出现时不存在，而在有反应的患者中却有所增加。单细胞 RNA 测序显示出一致的结果，以及信号通路和克隆大小的变化，与我们刚刚发表的大颗粒淋巴细胞白血病数据相似。特别有趣的是，造血室的扩张主要发生在更定型的成熟干细胞中。在针对未经治疗的疾病的第二个临床方案中，我们启动低风险口服疗法环孢素和艾曲博袋，以便尽早引入免疫抑制和干细胞刺激，并防止造血细胞因 T 细胞杀伤而损失。远程医疗在大流行期间尤其有用——已用于招募和跟踪患者，直到他们被送入临床中心进行明确的抗胸腺细胞球蛋白输注（如果需要）。意外的不良事件，特别是药物毒性、诊断错误以及患者对门诊就诊和医生指示的依从性非常好，反应率很高或优于标准治疗方案。我们评估雷帕霉素（西罗莫司）作为淋巴细胞毒性耐受剂的复发预防试验持续进行。研究药物的耐受性良好。我们的回顾性数据表明，未来的方案，最好是多中心方案，应在较早的时间点（大约六个月）测试西罗莫司，此时环孢素剂量急剧减少并停用艾曲波帕。 我们的免疫骨髓衰竭小鼠模型不断产生有趣且重要的数据。基于我们对巨噬细胞和肿瘤坏死因子在病理免疫反应中的作用的发现，我们进行了实验来测试先天免疫系统的其他组成部分。正如之前报道的，Toll 受体和多种细胞因子似乎在该模型中不起作用。然而，骨髓抑制细胞在减少 T 细胞反应和改善造血衰竭方面具有活性。细胞疗法已用于移植物抗宿主病，并可能对难治性免疫骨髓衰竭有用。我们在小鼠模型中广泛测试了商业 Jak1/Jak2 抑制剂鲁索替尼 (ruxolitinib) 的治疗效果。这种药物作为小鼠食物的成分摄入。与我们之前使用各种免疫抑制剂的经验相比，鲁索替尼在输注淋巴结细胞之前给药不仅可以完全预防骨髓衰竭，而且甚至在输注几天后也能有效。短暂接触药物后，患者的生存率非常好，长期血细胞计数和骨髓细胞结构基本正常，并且仅有少量残留干细胞损伤的证据。血浆细胞因子保持正常，预期的信号传导途径被该 jakinib 阻断。模型中接受治疗的动物和健康动物的药物毒性都很小。这些结果支持鲁索替尼治疗多种免疫骨髓疾病、复发性难治性 AA 以及低风险 MDS 和纯红细胞再生障碍性贫血的临床试验，并有可能作为 ATG 的替代品，避免这种不完全定义的生物制剂带来的住院和输注风险。