B cell function and phenotype as predictors of therapeutic response to rituximab

描述（由申请人提供）：尽管尚未确定B细胞在疾病发病机制中的特定作用，但B细胞在动物模型和人体中均与T1 D的发生密切相关。与这一想法一致，最近已证明利妥昔单抗的B细胞耗竭疗法在一些新发T1 D个体中是有效的治疗。我们已发表的和初步的研究表明，携带与T1 D强烈相关的PTPN 22 1858 T变体等位基因的健康受试者表现出B细胞抗原受体（BCR）信号转导受损和B细胞发育改变。引人注目的是，我们还发现，在大多数T1 D受试者中，B细胞信号传导和发育发生了几乎相同的变化，与其PTPN 22基因型无关。此外，新出现的数据也已开始牵连改变B调节（布雷格）功能在人类自身免疫性疾病。总之，这些发现意味着改变的B细胞信号传导包括参与T1 D发病机制的常见表型。在本申请中，我们提出检验以下假设：B细胞信号传导和表型的改变：a）在T1 D受试者的至少一个亚组中包括固定缺陷，这将通过T1 D队列的自然史分析而明显;和B）可以预测T1 D受试者对利妥昔单抗的B细胞耗竭疗法的应答。 我们将通过两个具体目标来检验这些假设。首先，我们将描述B细胞信号转导在个人之前和T1 D疾病发作时。我们将使用从TrialNet自然史研究中获得的库存血液样本，在新发T1 D与年龄匹配的同胞对照的血液样本中分别比较BCR触发的p-PLC g2和CD 40 L驱动的IL 10表达和pSTAT 3。我们将确定是否改变B细胞信号是目前在疾病发作以及临床疾病之前。我们的数据也将被描述为B细胞区室的总体组成和关键自身免疫相关基因产物的SNP基因分型。其次，我们将描述TrialNet利妥昔单抗研究参与者的B细胞信号传导。我们将在治疗前比较应答者与非应答者的B细胞信号传导和亚群，以确定信号传导是否与对治疗的应答相关。接下来，我们将使用在治疗后0和12个月获得的样品检查每个受试者中的信号传导活性。此外，我们还将探讨利妥昔单抗治疗是否在B细胞库恢复后调节这些缺陷;和/或纠正是否与对治疗的反应相关。最后，我们还将描述这些结果与SNP分析。将我们的研究结果与来自自然史和利妥昔单抗干预研究的TrialNet样本联系起来，提供了一个独特的机会来测试改变的B细胞信号传导可能促进T1 D耐受性的破坏和/或调节对致耐受性治疗的反应。如果成功，这项工作将定义新的生物标志物，用于识别和监测T1 D患者，这些患者可能会从未来的临床试验中受益，这些临床试验使用替代靶向策略来实现长期免疫耐受。 公共卫生相关性：B细胞与T1 D的发展密切相关，最近已证明利妥昔单抗的B细胞耗竭疗法在一些新发T1 D个体中是有效的治疗。我们发表的和初步的研究表明，改变B细胞信号传导包括一个共同的表型，参与发病机制的T1 D。在本申请中，我们将检验以下观点：B细胞信号传导的改变：a）代表T1 D受试者中通过自然史分析明显的固定缺陷;和B）可以预测对B细胞耗竭疗法的应答。

DESCRIPTION (provided by applicant): Although the specific role(s) for B cells in disease pathogenesis has not been established, B cells are strongly implicated in development of T1D both in animal models and in humans. Consistent with this idea, B cell depletion therapy with rituximab has recently been shown to be an effective treatment in some individuals with new onset T1D. Our published and preliminary studies indicate that healthy subjects, who carry the PTPN22 1858T variant allele strongly associated with T1D, exhibit impairment in B cell antigen receptor (BCR) signal transduction and altered B cell development. Strikingly, we have also identified nearly identical changes in B cell signaling and development in the majority of T1D subjects independent of their PTPN22 genotype. In addition, emerging data have also begun to implicate altered B regulatory (Breg) function in human autoimmune disorders. Together, these findings imply that altered B cell signaling comprises a common phenotype that participates in the pathogenesis of T1D. In this application, we propose to test the hypotheses that alterations in B cell signaling and phenotype: a) comprise a fixed deficit in at least a subset of T1D subjects that will be evident via natural history analysis of T1D cohorts; and b) may predict the response of T1D subjects to B cell depletion therapy with rituximab. We will test these hypotheses via two Specific Aims. First, we will characterize B cell signal transduction in individuals prior to and at the time of T1D disease onset. We will compare BCR-triggered p- PLCg2 and CD40L-driven of IL10 expression and pSTAT3, respectively, in blood samples derived from new onset T1D vs. age matched sibling controls using banked blood samples obtained from the TrialNet natural history study. We will determine if altered B cell signaling is present at disease onset as well as prior to clinical disease. Our data will also be characterized with respect to the overall composition of the B cell compartment and SNP genotyping for key autoimmune-associated gene products. Second, we will characterize B cell signaling in participants in the TrialNet rituximab study. We will compare B cell signaling and subsets prior to therapy in responders vs. non-responders to determine whether signaling correlates with response to therapy. Next, we will examine signaling activity in each subject using samples obtained at time 0 and 12 months post therapy. Further, we will address whether rituximab treatment modulates these defect(s) upon recovery of the B cell pool; and/or whether correction correlates with response to therapy. Finally, we will also characterize these outcomes with respect to SNP analysis. Linking our findings to TrialNet samples from both natural history and rituximab intervention studies provides a unique opportunity to test the idea that altered B cell signaling may promote a break in tolerance and/or modulate the response to tolerogenic therapies in T1D. If successful, this work will define new biomarkers for identifying and monitoring T1D patients that might benefit from future clinical trials using alternative targeting strategies to achieve long-term immune tolerance. PUBLIC HEALTH RELEVANCE: B cells are strongly implicated in development of T1D and B cell depletion therapy with rituximab has recently been shown to be an effective treatment in some individuals with new onset T1D. Our published and preliminary studies imply that altered B cell signaling comprises a common phenotype that participates in the pathogenesis of T1D. In this application, we will test the idea that alterations in B cell signaling: a) represent a fixed deficit in T1D subjects evident via natural history analyses; and b) may predict the response to B cell depletion therapy.