Predictors for drug selection and minimization in pediatric liver transplantation

该项目的长期目标是尽量减少器官排斥反应和免疫抑制剂毒性， 儿童肝移植（LTx）前LTx淋巴细胞耗竭允许类固醇避免和降低 需要他克莫司免疫抑制剂。如果能更好地理解潜在的机制， 用于进一步减少药物最小化期间的原发性排斥反应（50%）和复发性排斥反应（30%）， 这个协议。初步工作使我们假设供体特异性低反应性和调节性- 在儿童LTx早期排斥反应中， 无类固醇淋巴细胞耗竭免疫抑制。我们进一步假设， 免疫调节与延伸的MHC中的单核苷酸多态性（SNP）模式相关， 促进增殖、凋亡、记忆和B细胞依赖功能的区域基因。的临床试验 我中心将在用5 mg/kg兔抗人胸腺细胞耗尽后给予无类固醇的他克莫司 对80例LTx患儿进行rATG检测。拟议的机械增编研究将需要一系列 LTx前和LTx后1个月、3个月和12个月所有儿童的外周血样本。具体目标是1。 供体特异性同种异体反应性、T-reg/抑制细胞（CD 4 + CD 25+、CD 8 +28-）的纵向表征， 和抗HLA alto抗体，2.分布在14个SNP中的29个SNP的Pre-LTx表征 MHC基因，其初步分布模式在排斥者之间显著不同（活检证实 LTx后60天的排斥）和非排斥者。这将在80名儿童及其亲生父母中进行。 SNP显示>或< 50%的预期从父母到拒绝者的传播，并且其传播不同 显着之间的排斥和非排斥，将用于确定候选基因座的传输 不平衡检验; 3.通过a）测量结果组内的潜在候选基因/基因座， 通过CFSE-MLR在T和B细胞亚群中的供体特异性增殖/凋亡/记忆应答，B）整体 基因组mRNA表达以补充SNP关联，并使假阳性最小化，以及c）基因座- 候选基因座的特异性基因表达（mRNA）c）。如果成功，研究结果的未来应用可以 改进的LTx前药物选择，例如，如果SNP模式预测排斥，则分配类固醇。此外，LTx后药物 可以使最小化更安全，例如，当出现T-reg/T-sup时。

The long term goal of this project is to minimize organ rejection and immunosuppressant toxicity, in each child with liver transplantation (LTx). Pre-LTx lymphocyte depletion permits steroid avoidance and lowers need for Tacrolimus immunosuppression. If underlying mechanisms were better understood, they could be used to reduce further, primary rejection (50%) and recurrent rejection during drug minimization (30%) on this protocol. Preliminary work leads us to hypothesize that donor-specific hyporeactivity and regulatory- suppressive effect are achieved at highly variable intervals among pediatric LTx with early rejection after steroid-free lymphocyte-depleting immunosuppression. We further hypothesize that this variability in immune-modulation is associated with patterns of single nucleotide polymorphisms (SNP) in extended MHC- region genes subserving proliferation, apoptosis, memory and B-cell-dependent functions. A clinical trial at our center will administer steroid-free Tacrolimus after depletion with 5 mg/kg rabbit anti-human-thymocyte globulin (rATG) to 80 children with LTx. The proposed mechanistic addendum study will entail serial peripheral blood samples from all children before and at 1, 3, and 12 months post-LTx. Specific aims are 1. Longitudinal characterization of donor-specific alloreactivity, T-reg/suppressor cells (CD4+CD25+, CD8+28-), and anti-HLA alto-antibodies in each child, 2. Pre-LTx characterization of 29 SNPs distributed among 14 MHC genes, whose preliminary distribution patterns differ significantly between rejectors (biopsy-proven rejection at 60 days post-LTx), and non-rejectors. This will be done in 80 children and their biologic parents. SNPs showing > or < 50% expected transmission from parents to rejectors and whose transmission differs significantly between rejectors and non-rejectors, will be used to identify candidate loci with the transmission disequilibrium test, and 3. Validate potential candidate genes/loci within outcome groups, by a) measuring donor-specific proliferative/apoptotic/memory responses in T- and B-cell subsets by CFSE-MLR, b) whole genome mRNA expression to complement SNP associations, and minimize false-positives, and c) locus- specific gene expression (mRNA) for candidate loci c). If successful, future application of study results could improve pre-LTx drug selection, e.g.,allocating steroids if SNP patterns predict rejection. Also, post-LTx drug minimization could be made safer, e.g., when T-reg/T-sup appear.