Evaluation of patients with ALPS-like syndromes

该项目继续产生以慢性淋巴结病、脾肿大和自身免疫现象为特征的新定义综合征。最初，这涉及到阿尔卑斯山样患者，他们的功能获得突变涉及编码NRAS和KRAS的基因。这导致了RAS-RAF-ERK通路的过度激活和促凋亡蛋白BIM的抑制。这反过来又导致IL-2停用后缺陷T细胞的凋亡，但正常的T细胞和B细胞对星状孢子素、依托泊苷、顺铂和放射的反应以及正常的Fas通路诱导的凋亡。低水平的BIM也影响T细胞再激活所诱导的细胞凋亡。这些初步观察导致确定了12名躯体功能获得NRAS或KRAS突变的患者，其中许多人在儿童早期表现为具有急性粒-单核细胞白血病(AMML)特征的表型，但它不是一种不同于AMML的侵袭性或恶性疾病。这种疾病现在被命名为RAS相关性白质增生性疾病(RALD)。我们正在研究更好地定义如何将这种体细胞NRAS突变疾病与导致JMML的相同突变基因区分开来的潜在标记。 最近，我们已经确定了另外两种与阿尔卑斯综合征有共同特征的遗传性疾病，评估的患者来自转诊到NIH以排除阿尔卑斯山的患者队列。在这些新症状中包括一名儿童，其蛋白激酶C Delta纯合子功能缺陷导致淋巴肿大，B细胞过度增殖，CD5+/CD20+B细胞增殖，免疫球蛋白增加，自身抗体产生和B细胞凋亡缺陷，以及与NK细胞功能缺陷相关的慢性EBV病毒血症。PKC Delta基因敲除可重现正常单个核细胞B细胞过度增殖的体外表现，野生型PKC Delta基因插入可部分挽救PMA诱导的B细胞凋亡缺陷。这位患者定义了一个新的实体，在单基因凋亡缺陷中，主要影响B细胞，也干扰正常的NK细胞毒性(后者目前机制不明)，似乎增加了对慢性EBV病毒血症的易感性。重要的是，该患者对雷帕霉素治疗反应显著，脾肿大明显减少，B细胞活化减弱。最近，我们确定了一组PI3激酶p110杂合突变患者的特征，该突变导致该蛋白功能增强，与鼻肺感染、淋巴聚集和自身免疫相关的风险增加。这些患者的临床表型已经扩大到包括高IgM综合征样的表现，此外，这些患者患淋巴系统恶性肿瘤的风险增加。我们目前正在与诺华公司合作，启动一项临床试验，使用该公司开发的一种特定的PI3激酶p110抑制剂，并已完成第一阶段试验，证明其对人体没有毒性。FDA已经提供了对这项拟议的合作试验的初步审查，预计将于2015年初开始。免疫学服务将提供特定的流式细胞仪和细胞内功能测试，作为此次临床试验监测计划的一部分。 最后，转诊队列中排除阿尔卑斯病的额外患者样本正在评估基因组DNA水平上的新免疫缺陷或上述缺陷。

This project has continued to generate newly defined syndromes characterized by chronic lymphadenopathy, splenomegaly and autoimmune phenomena. Initially this involved ALPS-like patietns with gain-of-function mutations involving the genes that encode NRAS and KRAS. These resulted in the hyperactivation of the RAS-RAF-ERK pathway and suppression of the pro-apoptotic protein BIM. This in turn resulted in defective T cell apoptosis after IL-2 withdrawal, but normal T cell and B cell apoptosis in response to staurosporine, etoposide, cisplatin and radiation as well as a normal Fas pathway induction of apoptosis. The low levels of BIM also affected the apoptosis induced by T-cell reactivation. These intial observations have lead to identifying 12 patients with somatic gain of function NRAS or KRAS mutations with many presenting early in childhood with a phenotype that shares features of acute myelomonocytic leukemia (AMML) but it is not an aggressive or malignant disorder unlike AMML. This disroder is now named RAS Associated Leukoproliferative Disorder (RALD). We are workng on potential markers that better define how to distinguish this somatic NRAS mutation disorder from the same mutatons that result in JMML. Most recently we have characterized two additional genetic disorders that share certain features with ALPS and the patients evaluated came from the cohort of patients refered to the NIH to rule out ALPS. Included among these new syndromes is a child with a homozygous loss of function defect in protein kinase C delta that causes lymphadenopathy, B cell hyperproliferation, expansion of CD5+/CD20+ B cells, increased immunoglobulins, autoantibody production and defective B cell apoptosis as well as chronic EBV viremia associated with a defect in NK cell function. The ex vivo findings of B cell hyperproliferrration could be recapitulated in normal mononuclear cells by PKC delta knock down and the patient EBV transsformed B cells could be partially rescued from the ex vivo PMA induced apoptotic defect by insertion of wild-type PKC delta. This patient defines a new entity in monogenic apoptotic defects that primarily affects B cells and also interferes with normal NK cell cytotoxicity (the latter for at present an unknown mechanism) that appears to increase the susceptibility to chronic EBV viremia. Importantly this patient responded dramatically to rapamycin therapy with marked decrease in the massive splenomegaly and dimiinished B cell activation. Most recently, we have characterized a group of patients with heterozygous mutations in PI3 kinase p110 that result in a gain of function of this protein associated with incresaed risk for sinopulmonary infections, lymphoaccumulation and autoimmunity. The clinical phenotype of these patients has expanded to include a hyper IgM syndrome like presenation and in addition these patients have an increased risk for lymphoid malignancy. We are currently working with Novartis on the initiation of a clinical trial used a specific inhibitor of PI3 kinase p110 that the company developed and has completed phase 1 trials demonstrating its lack of toxicity in humans. The FDA has already provided preliminary review of this proposed cooperative trial and it is anticipated that this will start in early 2015. The Immunology Service will provide specific flow cytometric and intracellular functional testing as part of the monitoring program for this clinical trial. Finally, additional patient samples within the referral cohort to rule out ALPS, in whom ALPS and RALD have been ruled out, are being evaluated for either new immunologic defects at the genomic DNA level or for the defects noted above.