Allorecognition of HLA-DP by CD4+ T cells is affected by polymorphism in its alpha chain

Alloreactivity to HLA-DP molecules, class II heterodimers of an oligomorphic alpha and a polymorphic beta chain, is increasingly being studied due to its relevance in clinical transplantation. We hypothesized that not only polymorphisms in the peptide binding groove encoded by exon 2 of HLA-DPB1, but also in other regions of the molecule and the alpha chain, could play a role in CD4+ T cell allorecognition. To test this possibility, we comparatively investigated CD4+ T cell allorecognition, measured by upregulation of the activation marker CD137, against HLA-DPB1*13:01, *05:01, *03:01, *17:01 or their allele counter parts DPB1*107:01, *135:01, *104:01, *131:01, with identical exon 2 sequences but polymorphism in exons 1, 3 or 4, in the context of different HLA-DPA1 (DPA1) polymorphisms (DPA1*01:03 and *02:01). No significant differences in CD4+ T cell allorecognition levels could be demonstrated for any of the beyond exon 2 DPB1 variants studied. Interestingly, however, the mean fold change in CD4+ CD137+ cells was significantly higher when the target shared at least one DPA1 allele with the allogeneic stimulator, compared to a distinct DPA1 background (1.65 vs 0.23, P < 0.005). Structural homology modeling suggested specific amino acid residues in the alpha chain, in particular position 31, to impact CD4+ T cell allorecognition of HLA-DP. Our data argue against a significant role of beyond exon 2 DPB1 polymorphisms for T cell alloreactivity, but show relevance of DPA1 polymorphism in this mechanism. These new findings impact HLA matching strategies in unrelated stem cell transplantation.     

CD34 Selected Cells for the Treatment of Poor Graft Function after Allogeneic Stem Cell Transplantation

Poor graft function (PGF) is characterized by pancytopenia and a hypoplastic marrow, with complete donor chimerism, usually without severe graft-versus-host disease (GVHD). We report 41 patients with PGF, treated with granulocyte colony-stimulating factor–mobilized CD34 selected cells, at a median interval from transplant of 140 days, without conditioning and without GVHD prophylaxis. Donors were HLA matched siblings (n = 12), unrelated donors (n = 18), or mismatched family members (n = 11). The median number of infused CD34⁺ cells was 3.4 × 10⁶/kg. The rate of trilineage recovery was 75%: 83% for HLA matched siblings and 72% for unrelated and mismatched family members (P = .3). The cumulative incidence of acute grade II GVHD was 15%, and no patient developed de novo chronic GVHD. The actuarial 3-year survival is 63%: 76% and 25% for patients with or without trilineage recovery. These data confirm the role of CD34⁺ selected cells from the same donor in the treatment of PGF and warrant the request for a second donation also when the donor is unrelated.     

High Serum Level of Antithymocyte Globulin Immediately before Graft Infusion Is Associated with a Low Likelihood of Chronic,But Not Acute,Graft-versus-Host Disease

Rabbit antithymocyte globulin (ATG) is administered during transplant conditioning to decrease the risk of both acute graft-versus-host disease (aGVHD) and chronic graft-versus-host disease (cGVHD). Here we evaluated the relationship between the serum concentration of ATG (capable of binding to lymphocytes) immediately before graft infusion (day 0) or on day +7 or +28 post-transplantation and the development of aGVHD or cGVHD. We studied 180 patients whose conditioning included 4.5 mg/kg antithymocyte globulin (ATG; Thymoglobulin). For aGVHD, we found no association with ATG levels on day 0. Nevertheless, high day +7 and +28 ATG levels were associated with a low likelihood of aGVHD. For cGVHD, high ATG levels at all 3 time points (days 0, +7, and +28) were associated with a low likelihood of cGVHD. In conclusion, high-dose ATG administration at the time of graft infusion appears to inhibit the development of cGVHD, but not aGVHD; however, higher ATG levels on days +7 and +28 are associated with lower rates of both aGVHD and cGVHD.     

Fractional CO2 laser for the treatment of sclerodermatous cGVHD

ABSTRACT

Sclerodermatous graft versus host disease (sclGVHD) is a debilitating complication of hematopoietic stem cell transplant and is characterized by skin thickening and fibrosis that can result in severe contractures. While immunosuppressive therapy remains a mainstay of treatment, the disease course often progresses and, in severe cases, renders patients immobile and wheelchair-bound. Lasers that can target sclerotic lesions to improve tissue pliability and restore range of motion are a promising potential treatment for sclGVHD. Fractional CO2 lasers promote selective collagen remodeling by creating microcolumns of thermal injury that stimulate a wound healing response. Here, we present 2 patients with sclGVHD who underwent treatment with fractional ablative CO2 laser. In this pilot case series demonstrating the novel use of CO2 laser for severe, refractory sclGVHD, two patients were treated with fractional ablative CO2 laser to a focal area of sclerosis. One patient also received clobetasol ointment under occlusion in between treatments. Both patients reported marked subjective improvement in pain and mobility. Objective measurements were recorded for patient 2 who gained roughly 10 degrees of extension and 2 degrees of flexion, as well as a 10% reduction in skin thickness in the treated area. CO2 laser therapy with or without clobetasol ointment under occlusion is a promising treatment modality for sclGVHD.     

利用TCR V_β基因分析GVHD患者的克隆性T细胞

应用RT PCR扩增 3例异基因造血干细胞移植术后合并慢性GVHD患者的外周血单个核细胞的TCRVβ 2 4个亚家族的CDR3,了解患者TCRVβT细胞的表达 ,PCR产物进一步经基因扫描分析确定T细胞克隆性。结果显示 ,3例患者均有克隆性T细胞生长 ,它可能与GVHD的发生有关。     

单倍体相合骨髓移植小鼠GVHD靶器官的器官特异性T细胞受体克隆谱型的分子特征

本课题通过单倍体相合骨髓移植小鼠模型,研究GVHD靶器官的器官特异性T细胞受体谱型特点,以及GVHD靶器官克隆性T细胞的TCRBV CDR3分子特征。建立单倍体相合异基因移植小鼠GVHD模型,应用RT—PCR扩增小鼠肝脏、皮肤、回肠等组织移植前后TCRBV20个家族的基因序列,通过基因扫描判断TCRBV家族的克隆表达、CDR3克隆性质。对于寡克隆表达的TCRBV家族在长泳道测序胶上电泳,对部分单克隆条带测序,得到一组肝脏、皮肤、回肠在移植后不同时间与GVHD相关的TCRBV CDR3的分子。结果表明：单倍体相合骨髓移植小鼠在移植后14天临床开始出现典型的GVHD表现。移植后受鼠肝脏、皮肤、远端回肠等均出现典型的GVHD病理表现,在其T细胞受体谱型图上出现了分属TCRBV家族的单克隆或寡克隆增生的T细胞。肝脏、皮肤、回肠等GVHD的靶器官中部分克隆性增生的T细胞TCRBV CDR3分子存在一些C’末端保守的CDR3氨基酸基序（motif）。结论：单倍体相合异基因移植后发生GVHD的组织可出现T细胞单克隆及寡克隆增生,GVHD相关T细胞克隆共用一些保守的TCRBV CDR3基序,识别类似的抗原。     

杀伤细胞免疫球蛋白样受体基因及其配体相合或错配对单倍相合骨髓移植效果的影响

本研究分析杀伤细胞免疫球蛋白样受体（killer cell Ig-like receptor,KIR）及其配体分子相合与否对单倍体相合骨髓移植效果的影响。分析了74例KIR基因及其配体分子HLA-Cw的分布频率和特点,同时比较KIR分子配体缺失与否对单倍相合骨髓移植患者总体生存、无病生存、GVHD发生以及复发等的影响。结果表明：19个KIR基因表型中2DL1、2DL4和3DL2-3在所有个体100%分布,其他高频率分布的还有3DP1（98.6%）、2DP1（98.6%）、3DL1（97.3%）、2DL3（97.3%）;抑制型基因分布频次是活化型的1.37倍;所有单倍体都含有2DL1、KIR3DL2、3DL3和2DL4,其中每个单倍体中均含有2DL2和/或2DL3。HLA-C14个等位基因中Cw7分布频率最高为37.8%;KIR2DL2/2DL3识别配体Group2（HLA-Cw1,3,7,8,13,14）组占43.2%。32例单倍相合骨髓移植中KIR基因错配发生比例为43.8%,其中9/14例为2DL不相合、5/14为2DL2或3DL1不相合;46对单倍相合骨髓移植中HLA-Cw全相合者29例,不相合者14例,HLA-Cw发生完全错配比例为30.4%,全相合比例为63.4%。14例KIR基因不相合和13例KIR基因相合移植病例中,KIR基因相合组生存率高于KIR基因不相合者（p=0.032）;17例KIR分子配体HLA-Cw不相合移植患者的DFS明显高于24例相合者（p=0.024）。按供受者KIR配体是缺失的GVHD矢量组生存率高于非GVHD矢量组（p=0.015）。急性重症GVHD发生与活化型KIR2DS1/2DS2有关,2DS1/2DS2不相合组高发急性重症GVHD同时复发减低,而2DS1/2DS2相合组低GVHD但是复发增多。14例KIR配体不相合髓系白血病患者骨髓移植后1例复发死亡,而12例KIR配体相合组患者有4例复发死亡。结论：单倍体相合骨髓移植的主要特点就是HLA不全相合,KIR基因表型不一致性及其配体缺失也是其主要免疫学特征,供者型KIR配体的缺失与移植效果有密切关系,在单倍相合移植中分析KIR基因及其配体对于供者选择和判断预后有重要意义。