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

描述（由申请人提供）：虽然B细胞在疾病发病机制中的具体作用尚未确定，但B细胞在动物模型和人类中都与T1D的发展密切相关。与这一观点相一致的是，B细胞消耗疗法联合利妥昔单抗最近被证明是一些新发T1D患者的有效治疗方法。我们已发表的研究和初步研究表明，携带与T1D密切相关的PTPN22 1858T变异等位基因的健康受试者表现出B细胞抗原受体（BCR）信号转导障碍和B细胞发育改变。引人注目的是，我们还在大多数T1D受试者中发现了几乎相同的B细胞信号传导和发育变化，与PTPN22基因型无关。此外，新出现的数据也开始涉及人类自身免疫性疾病中B调节（Breg）功能的改变。总之，这些发现表明改变的B细胞信号包括参与T1D发病机制的共同表型。在此应用中，我们建议测试B细胞信号传导和表型改变的假设：a)至少在T1D受试者的一个子集中包含固定缺陷，这将通过T1D队列的自然历史分析来证明；b)可以预测T1D患者对利妥昔单抗b细胞消耗治疗的反应。我们将通过两个具体目标来检验这些假设。首先，我们将描述个体在T1D疾病发病前和发病时的B细胞信号转导。我们将比较bcr触发的p- PLCg2和cd40l驱动的IL10表达和pSTAT3，分别来自新发T1D患者的血液样本和年龄匹配的同胞对照，使用从TrialNet自然历史研究中获得的血液样本。我们将确定改变的B细胞信号是否存在于疾病发病以及临床疾病之前。我们的数据还将以B细胞区室的整体组成和关键自身免疫相关基因产物的SNP基因分型为特征。其次，我们将对TrialNet利妥昔单抗研究参与者的B细胞信号传导进行表征。我们将比较反应者和无反应者治疗前的B细胞信号传导和亚群，以确定信号传导是否与治疗反应相关。接下来，我们将使用治疗后0个月和12个月获得的样本检查每个受试者的信号活动。此外，我们将探讨美罗华治疗是否能在B细胞池恢复时调节这些缺陷；和/或矫正是否与治疗反应相关。最后，我们还将根据SNP分析来描述这些结果。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检验改变的B细胞信号传导可能促进T1D耐受性的中断和/或调节对耐受性原性治疗的反应。如果成功，这项工作将定义用于识别和监测T1D患者的新生物标志物，这些标志物可能会从未来的临床试验中受益，使用替代靶向策略来实现长期免疫耐受。

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.