Results of unrelated umbilical cord blood hematopoietic stem cell transplantation

The number of umbilical cord blood transplants is increasing worldwide. The purpose of Eurocord is to evaluate the results and to compare the outcome of umbilical cord blood transplants with allogeneic bone marrow transplants. Data have been reported to Eurocord by multiple transplant centers. Close links have been established with the cord blood banks through Netcord. Bone marrow transplant data have been provided by transplant centers and also through the European Group for Blood and Marrow Transplantation (EBMT) and International Bone Marrow Transplant Registries (IBMTR). Eurocord has analyzed the outcome of unrelated umbilical cord blood transplants from 121 transplant centers and 29 countries. The results showed that survival with unrelated mismatched umbilical cord blood transplants was comparable to that with unrelated bone marrow transplants. Engraftment with cord blood was delayed, resulting in an increased incidence of early transplant complications. The incidence of acute and chronic graft-vs.-host disease was reduced with cord blood grafts even in human leukocyte antigen (HLA)-mismatched transplants and in adults. In patients with leukemia, the rate of relapse was similar to the rate of relapse after bone marrow transplant. The overall event-free survival with umbilical cord blood transplantation was not statistically different when compared to bone marrow transplants. This large registry study confirms the potential benefit of using umbilical cord blood hematopoietic stem cells for allogeneic transplants.     

全程干预对造血干细胞移植患者营养状况的影响

目的探讨全程干预对异基因造血干细胞移植患者营养状况的影响。方法将128例异基因造血干细胞移植患者随机分成两组,观察组67例患者营养状况采用全程护理干预,对照组61例患者进行常规护理,并对两组患者移植前和移植后4周的体重、血清白蛋白、前蛋白进行测定,观察Ⅱ°以上口腔黏膜炎及腹泻发生情况。结果两组患者术后4周体重、血清白蛋白、前蛋白、Ⅱ°以上口腔黏膜炎、腹泻比较差异均具有统计学意义(均P0.05)。结论异基因造血干细胞移植患者移植前即开展营养评估、制定营养指导计划,移植期间全程跟踪干预,可降低营养不良程度,减少术后并发症的发生,提高生活质量。     

Heterogeneous impact of cytomegalovirus reactivation on nonrelapse mortality in hematopoietic stem cell transplantation

This study aims to retrospectively analyze the efficacy of penciclovir in the prevention of viral infection after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Ninety-six patients with allo-HSCT were enrolled, who were treated at the Medical Center of Hematology of Xinqiao Hospital from June 2020 to September 2021. The experimental and control groups were treated with penciclovir and acyclovir, respectively, to prevent viral infection. By February 2022, the infection rates of cytomegalovirus, BK virus, JC virus, and Epstein-Barr virus (EBV) in the experimental group and the control group were 18.8% and 39.06% (P<0.05), 28.1% and 25% (P>0.05), 6.2% and 7.81% (P>0.05), 21.8% and 23.43% (P>0.05), respectively. The infection-related urinary system symptoms of the experimental group and the control group occurred in 4 and 9 patients, respectively, of which 3 and 9 patients died, respectively. Penciclovir can significantly reduce the cytomegalovirus infection rate after allo-HSCT and has better preventive effects than acyclovir without obvious side effects. The effectiveness and safety of penciclovir will be further verified in the future.     

间充质干细胞在造血干细胞移植中的应用

间充质干细胞(MSCs)是一种具有自我更新和多向分化潜能的成体干细胞,存在于骨髓、脂肪组织、脐血及多种胎儿组织.它可分泌多种细胞因子及生长因子,促进造血干细胞(HSC)的增殖与分化.MSCs还具有免疫调节、抗炎和组织修复作用,可减轻移植物抗宿主病(GVHD)及其他移植相关并发症.     

Role of HLA in hematopoietic stem cell transplantation

ABO blood group incompatibility is not a contraindication for allogeneic hematopoietic stem cell transplantation (allo-HSCT). An increasing number of ABO-incompatible HSCT (ABOi-HSCT) procedures have been performed along with advances in donor selection over the years. Currently, whether the recipient-donor ABO incompatibility has detrimental effects on post-HSCT outcomes is a matter of debate. Discrepancies across studies referring to various graft sources, donor types, conditioning regimens, and the use of immunomodulators complicate interpretations of the clinical outcomes of ABOi-HSCT, such as transfusion requirements, graft-versus-host disease (GVHD), disease relapse, overall survival (OS), and non-relapse mortality (NRM). Isohemagglutinins (ISO) targeting red blood cell (RBC) antigens are associated with post-HSCT immunohematological complications, including hemolysis, passenger lymphocyte syndrome (PLS), and pure red cell aplasia (PRCA). Immunohematological events occur frequently and are sometimes difficult to handle in clinical practice. Therefore, it is necessary to form a deeper understanding on the mechanism and a comprehensive management scheme for recipients of ABOi-HSCT. In this review, we summarized literature of the impact of ABO incompatibility on post-HSCT outcomes and outlined important immune-mediated hematological events.     

Conjunctival Scarring in Trachoma Is Associated with the HLA-C Ligand of KIR and Is Exacerbated by Heterozygosity at KIR2DL2/KIR2DL3

Background

Chlamydia trachomatis is globally the predominant infectious cause of blindness and one of the most common bacterial causes of sexually transmitted infection. Infections of the conjunctiva cause the blinding disease trachoma, an immuno-pathological disease that is characterised by chronic conjunctival inflammation and fibrosis. The polymorphic Killer-cell Immunoglobulin-like Receptors (KIR) are found on Natural Killer cells and have co-evolved with the Human Leucocyte Antigen (HLA) class I system. Certain genetic constellations of KIR and HLA class I polymorphisms are associated with a number of diseases in which modulation of the innate responses to viral and intracellular bacterial pathogens is central.

Methodology

A sample of 134 Gambian pedigrees selected to contain at least one individual with conjunctival scarring in the F₁ generation was used. Individuals (n = 830) were genotyped for HLA class I and KIR gene families. Family Based Association Tests and Case Pseudo-control tests were used to extend tests for transmission disequilibrium to take full advantage of the family design, genetic model and phenotype.

Principle findings

We found that the odds of trachomatous scarring increased with the number of genome copies of HLA-C2 (C1/C2 OR = 2.29 _BHP-value = 0.006; C2/C2 OR = 3.97 _BHP-value = 0.0004) and further increased when both KIR2DL2 and KIR2DL3 (C2/C2 OR = 5.95 _BHP-value = 0.006) were present.

Conclusions

To explain the observations in the context of chlamydial infection and trachoma we propose a two-stage model of response and disease that balances the cytolytic response of KIR expressing NK cells with the ability to secrete interferon gamma, a combination that may cause pathology. The data presented indicate that HLA-C genotypes are important determinants of conjunctival scarring in trachoma and that KIR2DL2/KIR2DL3 heterozygosity further increases risk of conjunctival scarring in individuals carrying HLA-C2.     

KIR gene variability in cutaneous malignant melanoma: influence of KIR2D/HLA-C pairings on disease susceptibility and prognosis

Natural killer and CD8⁺ T cells are believed to be involved in the immune protection against melanoma. Their function may be regulated by a group of receptors defined as killer immunoglobulin-like receptors (KIRs) and their cognate HLA class I ligands. In this study, we analyzed the influence of KIR genes and KIR/HLA-I combinations on melanoma susceptibility and/or prognosis in a Spanish Caucasian population. For this purpose, KIR genotyping by PCR-SSP and HLA-C genotyping by reverse PCR-SSO were performed in 187 melanoma patients and 200 matched controls. We found a significantly low frequency of KIR2DL3 in nodular melanoma (NM) patients (P?=?0.001) and in ulcerated melanoma patients (P?<?0.0001). Similarly, the KIR2DL3/C1 combination was significantly decreased in melanoma patients (P _c?=?0.008) and in patients with sentinel lymph node (SLN) melanoma metastasis (P _c?=?0.002). Multivariate logistic regression models showed that KIR2DL3 behaves as a protective marker for NM and ulcerated melanoma (P?=?0.02, odds ratio (OR)?=?0.14 and P?=?0.04, OR?=?0.28, respectively), whereas the KIR2DL3/C1 pair acts as a protective marker for melanoma (P?=?0.017, OR?=?0.54), particularly superficial spreading melanoma (P?=?0.02, OR?=?0.52), and SLN metastasis (P?=?0.0004, OR?=?0.14). In contrast, the KIR2DL3(?)/C1C2 genotype seems to be correlated with NM and ulceration. We also report that the KIR2DL1(+)/S1(?)/C2C2 genotype is associated with susceptibility to melanoma and SLN metastasis. Altogether, the study of KIR2D genes and HLA-C ligands may help in assessing cutaneous melanoma risk and prognosis.     

KIR2DS1-positive NK cells mediate alloresponse against the C2 HLA-KIR ligand group in vitro

The inhibitory 2DL1 and activating 2DS1 killer Ig-like receptors (KIR) both have shared ligand specificity for codon sequences in the C2 group HLA-Cw Ags. In this study, we have investigated NK cell activation by allogeneic target cells expressing different combinations of the HLA-KIR ligand groups C1, C2, and Bw4. We demonstrate that fresh NK cells as well as IL-2-propagated NK cells from 2DS1-positive donors that are homozygous for the C1 ligand group are activated in vitro by B lymphoblastoid cell lines expressing the C2 group. This response is, in part, due to the absence of C1 group recognition mediated by the inhibitory receptor 2DL2/3. This "missing self" alloresponse to C2, however, is rarely observed in NK cells from donors lacking 2DS1. Even in presence of 2DS1, the NK alloresponse is dramatically reduced in donors that have C2 group as "self." Analysis of selected NK clones that express 2DS1 mRNA and lack mRNA for 2DL1 demonstrates that activation by the C2 ligand and mAb cross-linking of 2DS1 in these clones induces IFN-gamma. Furthermore, this C2 group-induced activation is inhibited by Abs to both HLA class I and the receptor. Collectively, these studies demonstrate that NK cells from 2DS1-positive donors are activated by target cells that express the C2 group as an alloantigen. This leads to increased IFN-gamma-positive fresh NK cells and induces NK allocytotoxicity in IL2-propagated polyclonal NK cells and NK clones. This study also provides support for the concept that incompatibility for the HLA-KIR ligand groups C1, C2, and Bw4 dominates NK alloactivation in vitro.     

造血干细胞移植术对肠道菌群结构的影响

目的监测造血干细胞移植术（Hematopoietic stem cell transplantation,HSCT）前后肠道菌群结构的动态变化。方法收集3例造血干细胞移植患者手术前后8个时间点的粪便样品,提取样品总DNA进行16S rRNA基因的V3区的bar coded 454焦磷酸测序,并用MANOVA、聚类分析、Pearson相关等统计方法对菌群结构的变化进行动态分析。结果 HSCT移植前,经过放、化疗及预防性抗生素治疗,患者的肠道菌群结构和组成发生显著的改变,多样性明显减少;移植4周后,菌群多样性有恢复的趋势,但菌群结构和组成与治疗前仍有明显的差异。整个HSCT过程中,Escherichia/Shigella及Enterococcus属变成肠道中最优势的细菌类群。结论肠道菌群结构在HSCT术前已发生显著的改变,机会致病菌Escherichia/Shigella及Enterococcus属成为HSCT患者肠道中最优势的细菌类群。     

Tie2/angiopoietin-1 signaling regulates hematopoietic stem cell quiescence in the bone marrow niche

The quiescent state is thought to be an indispensable property for the maintenance of hematopoietic stem cells (HSCs). Interaction of HSCs with their particular microenvironments, known as the stem cell niches, is critical for adult hematopoiesis in the bone marrow (BM). Here, we demonstrate that HSCs expressing the receptor tyrosine kinase Tie2 are quiescent and antiapoptotic, and comprise a side-population (SP) of HSCs, which adhere to osteoblasts (OBs) in the BM niche. The interaction of Tie2 with its ligand Angiopoietin-1 (Ang-1) induced cobblestone formation of HSCs in vitro and maintained in vivo long-term repopulating activity of HSCs. Furthermore, Ang-1 enhanced the ability of HSCs to become quiescent and induced adhesion to bone, resulting in protection of the HSC compartment from myelosuppressive stress. These data suggest that the Tie2/Ang-1 signaling pathway plays a critical role in the maintenance of HSCs in a quiescent state in the BM niche.     

The role of nutrition and effects on the cytokine milieu in allogeneic hematopoietic stem cell transplantation

Nutritional deficiency is very common after allogeneic stem cell transplantation (HSCT) despite careful assessment and nutritional supplementation (total parenteral or oral nutrition). The importance of nutrition in the immune system has been well defined during the past several years, as it has modulatory effects on the immune system. One of the most frequent questions in nutrition is whether nutritionally at-risk hosts have a defect in their immune system and whether such defects can be corrected by nutritional supplementation. Addressing nutritional supplementation starting from early post-transplantation might decrease the risk of infectious complication and GVHD after HSCT via the immunomodulatory role of a variety of nutrients and supplements. Given the well-established link between nutrition and immunomodulation, we hypothesize that timely nutritional supplementation can potentially play a direct or indirect role in decreasing non-relapse morbidity and mortality after HSCT. In this article, we discuss the possible link between nutritional deficiency and its effects on the cytokine milieu after HSCT.     

Prognostic impact of the simple L-index and absolute lymphocyte count early after allogeneic hematopoietic stem cell transplantation

Background aimsThe L-index, designed as a quantitative parameter to simultaneously assess the duration and severity of lymphopenia, and absolute lymphocyte count (ALC) have a prognostic impact after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, discrepancies have been reported in the impact of ALC, and limited information is currently available on the L-index.MethodsTo search for a better clinical tool, the authors retrospectively compared the simple L-index at 30 days (sL-index(30)), which aims to make the original L-index more compact, and ALC at 30 days (ALC(30)) after allo-HSCT in 217 patients who underwent allo-HSCT at the authors’ institutions.ResultsMedian sL-index(30) was 11 712 (range, 4419–18 511) and median ALC(30) was 404 (range, 0–3754). In a multivariate analysis, higher sL-index(30) was associated with a significantly higher cumulative incidence of relapse (CIR) (hazard ratio [HR], 1.01, 95% confidence interval [CI], 1.00–1.02, P = 0.02 for every increase of 100 in sL-index(30)) as well as non-relapse mortality (NRM) (HR, 1.02, 95% CI, 1.00–1.03, P = 0.01 for every increase of 100 in sL-index(30)). Although higher ALC(30) was associated with significantly lower CIR (HR, 0.94, 95% CI, 0.89–1.00, P = 0.04 for every increase of 100/μL in ALC(30)), it was not extracted as an independent risk factor for NRM (HR, 0.96, 95% CI, 0.88–1.05, P = 0.39). Higher sL-index(30) was associated with a slightly higher rate of grade 3–4 acute graft-versus-host disease (GVHD) (HR, 1.02, 95% CI, 1.00–1.04, P = 0.12 for every increase of 100 in sL-index(30)) but not chronic GVHD (HR, 1.00, 95% CI, 0.99–1.01, P = 0.63). ALC(30) was not associated with rates of grade 3–4 acute GVHD (HR, 1.02, 95% CI, 0.88–1.17, P = 0.81) or chronic GVHD (HR, 1.02, 95% CI, 0.98–1.06, P = 0.34). In a receiver operating characteristic curve, the cutoff values of sL-index(30) and ALC(30) for CIR were 9000 and 500, respectively, and the cutoff value of sL-index(30) for NRM was 12 000.ConclusionssL-index(30) is a promising tool that may be applied to various survival outcomes. A large-scale prospective study is needed to clarify whether medical interventions based on sL-index(30) values will improve the clinical prognosis of patients.     

Mutation at positively selected positions in the binding site for HLA-C shows that KIR2DL1 is a more refined but less adaptable NK cell receptor than KIR2DL3

Through recognition of HLA class I, killer cell Ig-like receptors (KIR) modulate NK cell functions in human immunity and reproduction. Although a minority of HLA-A and -B allotypes are KIR ligands, HLA-C allotypes dominate this regulation, because they all carry either the C1 epitope recognized by KIR2DL2/3 or the C2 epitope recognized by KIR2DL1. The C1 epitope and C1-specific KIR evolved first, followed several million years later by the C2 epitope and C2-specific KIR. Strong, varying selection pressure on NK cell functions drove the diversification and divergence of hominid KIR, with six positions in the HLA class I binding site of KIR being targets for positive diversifying selection. Introducing each naturally occurring residue at these positions into KIR2DL1 and KIR2DL3 produced 38 point mutants that were tested for binding to 95 HLA- A, -B, and -C allotypes. Modulating specificity for HLA-C is position 44, whereas positions 71 and 131 control cross-reactivity with HLA-A*11:02. Dominating avidity modulation is position 70, with lesser contributions from positions 68 and 182. KIR2DL3 has lower avidity and broader specificity than KIR2DL1. Mutation could increase the avidity and change the specificity of KIR2DL3, whereas KIR2DL1 specificity was resistant to mutation, and its avidity could only be lowered. The contrasting inflexibility of KIR2DL1 and adaptability of KIR2DL3 fit with C2-specific KIR having evolved from C1-specific KIR, and not vice versa. Substitutions restricted to activating KIR all reduced the avidity of KIR2DL1 and KIR2DL3, further evidence that activating KIR function often becomes subject to selective attenuation.     

Cholesterol sensitivity of KIR2.1 depends on functional inter-links between the N and C termini

In recent years, cholesterol has been emerging as a major regulator of ion channel function. We have previously shown that cholesterol suppresses Kir2 channels, a subfamily of constitutively active strongly rectifying K⁺ channels. Furthermore, our earlier studies have shown that cholesterol sensitivity of Kir2 channels depends on a group of residues that form a belt-like structure around the cytosolic pore of the channel in proximity to the transmembrane domain. In this study, we focus on the contributions of different structural domains of Kir2 channels in the regulation of their cholesterol sensitivity. Focusing on the mildest mutation in the sensitivity belt, L222I, we show that the sensitivity of the channel to cholesterol can be restored by crosstalk between three distinct cytosolic regions: the C-terminal CD loop, the EF and GA loops of the C-terminus, and the βA sheet of the N-terminus. Thus, in addition to the importance of residues that affect the cytosolic G-loop gate in the sensitivity of Kir2 channels to cholesterol, our data suggest an important role to the interactions at the interface between the channel’s N- and C- termini that couple the intracellular domains of its four subunits during gating.     

异基因造血干细胞移植后并发自身免疫性溶血性贫血的治疗进展

异基因造血干细胞移植（HSCT）后自身免疫性溶血性贫血（AIHA）是HSCT后并不少见的并发症,其发病率约1﹪~ 6﹪,不同于一般的AIHA,HSCT后AIHA发病机制尚未完全明确,可能与HSCT后受者体内免疫失调相关。危险因素与移植患者年龄小、非恶性疾病、使用无关供者、半相合供者移植、脐血移植、去T细胞移植及移植后并发慢性移植物抗宿主病（GVHD）等有关。皮质激素作为一线治疗,疗效有限,难以持续缓解,需联合使用利妥昔单抗（RTX）、大剂量丙种球蛋白等,甚至需要联合霉酚酸酯、环磷酰胺、西罗莫司、阿伦单抗、依库丽单抗或蛋白酶体抑制剂硼替佐米等免疫抑制剂治疗,部分患者需行血浆置换,偶有行脾切除术者。移植后AIHA总死亡率常高达50﹪,总体预后差于单纯AIHA。该综述旨在总结HSCT后并发AIHA的最新治疗进展,供临床医师参考。