Search

Summary Understanding the root causes of autoimmune diseases is hampered by the inability to access relevant human tissues and identify the time of disease onset. To examine the interaction of immune cells and their cellular targets in type 1 diabetes, we differentiated human induced pluripotent stem cells into pancreatic endocrine cells, including β cells. Here, we describe an in vitro platform that models features of human type 1 diabetes using stress-induced patient-derived endocrine cells and autologous immune cells. We demonstrate a cell-type-specific response by autologous immune cells against induced pluripotent stem cell-derived β cells, along with a reduced effect on α cells. This approach represents a path to developing disease models that use patient-derived cells to predict the outcome of an autoimmune response., Graphical Abstract, Highlights • β cell-specific response is achieved using iPSC-β cells and autologous immune cells • An in vitro immune response to iPSC-β cells requires ER stress • T cell activation is restricted to autologous iPSC-β cells • T cell activation is mediated by TCR engagement of peptide-HLA complexes on iPSC-β, Leite et al. describe an in vitro platform that models features of autoimmune type 1 diabetes using patient-derived endocrine cells and autologous immune cells. This represents a path to developing a model with patient-derived cells to predict and analyze the autoimmune response.

Summary Zika virus (ZIKV) and dengue virus (DENV) are two closely related flaviviruses that lead to different clinical outcomes. The mechanism for the distinct pathogenesis of ZIKV and DENV is poorly understood. Here, we investigate ZIKV and DENV infection of macrophages using a human pluripotent stem cell (hPSC)-derived macrophage model and discover key virus-specific responses. ZIKV and DENV productively infect hPSC-derived macrophages. DENV, but not ZIKV, infection of macrophages strongly activates macrophage migration inhibitory factor (MIF) secretion and decreases macrophage migration. Neutralization of MIF leads to improved migratory ability of DENV-infected macrophages. In contrast, ZIKV-infected macrophages exhibit prolonged migration and express low levels of pro-inflammatory cytokines and chemokines. Mechanistically, ZIKV disrupts the nuclear factor κB (NF-κB)-MIF positive feedback loop by inhibiting the NF-κB signaling pathway. Our results demonstrate the utility of hPSC-derived macrophages in infectious disease modeling and suggest that the distinct impact of ZIKV and DENV on macrophage immune response may underlie different pathogenesis of Zika and dengue diseases., Highlights • An hPSC-derived tissue-resident macrophage model for ZIKV and DENV infection • ZIKV-, but not DENV-, infected macrophages maintain migratory capacity • ZIKV, but not DENV, inhibits pro-inflammatory cytokines and chemokines expression • ZIKV disrupts NF-κB-MIF positive feedback loop by inhibiting NF-κB pathway, In this article, Tang and colleagues demonstrate the utility of hPSC-derived tissue-resident macrophages in infectious disease modeling and show differential responses of macrophages to ZIKV and DENV infection. ZIKV-, but not DENV-, infected macrophages exhibit prolonged migration and express low levels of pro-inflammatory cytokines and chemokines by disrupting the NF-κB-MIF positive feedback loop via inhibition of the NF-κB signaling pathway.

During pregnancy, semiallogeneic fetal extravillous trophoblasts (EVT) invade the uterine mucosa without being rejected by the maternal immune system. Several mechanisms were initially proposed by Peter Medawar half a century ago to explain this apparent violation of the laws of transplantation. Then, three decades ago, an unusual human leukocyte antigen (HLA) molecule was identified: HLA-G. Uniquely expressed in EVT, HLA-G has since become the center of the present understanding of fetus-induced immune tolerance. Despite slow progress in the field, the last few years have seen an explosion in our knowledge of HLA-G biology. Here, we critically review new insights into the mechanisms controlling the expression and function of HLA-G at the maternal-fetal interface, and discuss their relevance for fetal tolerance.

Background Recently, several studies have demonstrated a negative prognostic impact of Ikaros (IKZF1) gene alterations in acute lymphoblastic leukemia (ALL). However, controversies still exist regarding the impact of IKZF1 in current treatment protocols. Procedure We simultaneously detected IKZF1 gene deletions by multiplex ligation-dependent probe amplification and gene expression of IKZF1 isoforms in 206 children with BCR/ABL-negative ALL treated with ALL IC-BFM 2002 protocol, in which risk stratification was not based on minimal residual disease (MRD), and validated the results on a cohort of 189 patients treated with MRD-directed ALL-BFM 2000 protocol. Results Deletion of IKZF1 was present in 14 of 206 (7%) ALL IC patients. Interestingly, gene expression did not completely correlate with the deletion status in either cohort. Deletions were not always reflected in the gene expression of dominant-negative isoforms, and conversely, 7 of 395 (2%) non-deleted cases overexpressed dominant-negative isoform Ik6. IKZF1 deletions significantly affected event-free survival (EFS) of the ALL IC cohort (41 ± 14% vs. 86 ± 3%, P

Hurler's syndrome is an inborn error of mucopolysaccharide metabolism leading to premature death in childhood. Allogeneic hematopoietic SCT can achieve long-term survival by correcting the enzymatic deficiency. In an attempt to improve long-term engraftment and to reduce regimen-related toxicity (RRT), a prospective multicenter approach was initiated in Germany using a fludarabine-based radiation-free preparative regimen. Between 2001 and 2008, 12 children were enrolled. Median age at SCT was 14 months (range, 4-31 months). The conditioning regimen contained fludarabine, BU, melphalan and antithymocyte globulin. CD34 positively selected PBSC were used in 10 children with a matched unrelated donor. Median cell dose was 24.6 x 10(6) CD34+ cells per kg (range 10.0-54.8). Two children with a matched sibling donor received non-manipulated BM. Donor lymphocyte infusions were given in 6/12 children for mixed hematopoietic chimerism. At a median follow-up of 29 months (range 2-85 months), all children engrafted and have either stabilized or improved neurological function. In total, 12/12 patients showed donor-derived engraftment with 9/12 having full and 3/12 having mixed hematopoiesis. One developed acute GVHDor=grade II. RRTor=grade II was observed in two patients.

We report a retrospective analysis of 11 children with Down syndrome (DS) treated by SCT in eight German/Austrian SCT centres. Indications for transplantation were acute lymphoblastic leukaemia (N=8) and acute myeloid leukaemia (N=3). A reduced intensity conditioning (RIC) containing 2 Gy TBI was given to two patients, another five received a myeloablative regimen with 12 Gy TBI. Treosulphan or busulphan was used in the remaining four children. Four of eleven (36%) patients are alive. All of them were treated with a myeloablative regimen. One of the four surviving children relapsed 9 months after SCT and is currently receiving palliative outpatient treatment. The main cause of death was relapse (5/11). Two children died of regimen-related toxicity (RRT), one from severe exfoliative dermatitis and multiorgan failure after a treosulphan-containing regimen, the other from GvHD-related infections after RIC. Acute GvHD of the skin was observed in 10 of 10 evaluable patients, and chronic GvHD in 4 of 8. Our data show that DS patients can tolerate commonly used, fully myeloablative preparative regimens. The major cause of death is relapse rather than RRT resulting in an event-free survival of 18% and over all survival of 36%.

Acute lymphoblastic leukemia (ALL) is the most common malignancy of childhood and is treated with chemotherapy alone or, in particular subgroups, with additional radiation therapy and/or stem cell transplantation. The treatment intensity is adjusted according to prognostic factors associated with the risk of ALL recurrence. On Berlin–Frankfurt–Munster (BFM) protocols, the widely applicable early in vivo response to treatment as measured by the reduction of leukemic cells in the blood or bone marrow is currently the most important prognostic factor. However, although overall long-term cure rates for childhood ALL treated on risk-adapted protocols have dramatically improved over the last decades and, to date, are higher than 75%, a significant number of patients still die due to recurrent disease or the toxicity of treatment applied. One goal in future BFM trials will be to take advantage of a better molecular understanding of leukemia and host characteristics to dissect the mechanisms underlying the differences in treatment response. This short review focuses on the evolution of treatment response in BFM trials and provides a perspective on our strategy for improving molecular characterization of childhood ALL and implementing more individualized and novel therapeutic approaches.

Acute lymphoblastic leukemia (ALL) accounts for ∼25% of pediatric malignancies. Of interest, the incidence of ALL is observed ∼20% higher in males relative to females. The mechanism behind the phenomenon of sex-specific differences is presently not understood. Employing genome-wide genetic aberration screening in 19 ALL samples, one of the most recurrent lesions identified was monoallelic deletion of the 5' region of SLX4IP. We characterized this deletion by conventional molecular genetic techniques and analyzed its interrelationships with biological and clinical characteristics using specimens and data from 993 pediatric patients enrolled into trial AIEOP-BFM ALL 2000. Deletion of SLX4IP was detected in ∼30% of patients. Breakpoints within SLX4IP were defined to recurrent positions and revealed junctions with typical characteristics of illegitimate V(D)J-mediated recombination. In initial and validation analyses, SLX4IP deletions were significantly associated with male gender and ETV6/RUNX1-rearranged ALL (both overall P < 0.0001). For mechanistic validation, a second recurrent deletion affecting TAL1 and caused by the same molecular mechanism was analyzed in 1149 T-cell ALL patients. Validating a differential role by sex of illegitimate V(D)J-mediated recombination at the TAL1 locus, 128 out of 1149 T-cell ALL samples bore a deletion and males were significantly more often affected (P = 0.002). The repeatedly detected association of SLX4IP deletion with male sex and the extension of the sex bias to deletion of the TAL1 locus suggest that differential illegitimate V(D)J-mediated recombination events at specific loci may contribute to the consistent observation of higher incidence rates of childhood ALL in boys compared with girls.

Acute lymphoblastic leukemia (ALL) is a malignant disease of the white blood cells. The etiology of ALL is believed to be multifactorial and likely to involve an interplay of environmental and genetic variables. We performed a genome-wide association study of 355 750 single-nucleotide polymorphisms (SNPs) in 474 controls and 419 childhood ALL cases characterized by a t(12;21)(p13;q22) - the most common chromosomal translocation observed in childhood ALL - which leads to an ETV6-RUNX1 gene fusion. The eight most strongly associated SNPs were followed-up in 951 ETV6-RUNX1-positive cases and 3061 controls from Germany/Austria and Italy, respectively. We identified a novel, genome-wide significant risk locus at 3q28 (TP63, rs17505102, P(CMH)=8.94 × 10(-9), OR=0.65). The separate analysis of the combined German/Austrian sample only, revealed additional genome-wide significant associations at 11q11 (OR8U8, rs1945213, P=9.14 × 10(-11), OR=0.69) and 8p21.3 (near INTS10, rs920590, P=6.12 × 10(-9), OR=1.36). These associations and another association at 11p11.2 (PTPRJ, rs3942852, P=4.95 × 10(-7), OR=0.72) remained significant in the German/Austrian replication panel after correction for multiple testing. Our findings demonstrate that germline genetic variation can specifically contribute to the risk of ETV6-RUNX1-positive childhood ALL. The identification of TP63 and PTPRJ as susceptibility genes emphasize the role of the TP53 gene family and the importance of proteins regulating cellular processes in connection with tumorigenesis.Leukemia advance online publication, 11 November 2011; doi:10.1038/leu.2011.302.

Xenotransplantation of primary leukemia cells constitutes an attractive strategy to model disease for translational research, but the consequences of selective pressure on leukemia cells need to be clarified. Here we evaluate the phenotypic and genetic stability of primograft samples that were established by xenotransplantation of ALL cells from a group of patients with very high-risk precursor B-cell ALL, characterized by the persistence of minimal residual disease (VHR-ALL by MRD) after an intensive induction and consolidation therapy. Phenotypic properties remained unchanged, with concordant immunophenotypes in 9-10/10 leukemia-associated markers after up to 5 passages in Nod/scidIL2Rgammanull (NSG) mice and with stable drug response profiles in vitro on bone marrow stroma co-cultures. In 4/6 cases, 100 unsorted ALL cells were sufficient to reconstitute the leukemia. From up to 5 recurrent copy number abnormalities (CNA) detected in diagnostic samples, most were maintained in primografts. Changes in CNAs upon transplantation in NSG mice were few with 0-2 new lesions per case, mostly occurring during the first xenotransplantation. At the single cell level, the pattern of deletions in the CDKN2A/B locus revealed distinct subsets of ALL cells, which could reproducibly be tracked in primografts. These results provide unequivocal data for the existence of clonally closely related but distinct subsets of leukemia initiating cells in ALL, which has important implications for the use of this model for translational research. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5330. doi:10.1158/1538-7445.AM2011-5330

Despite considerable improvements regarding treatment outcome about 20% of children with acute lymphoblastic leukemia (ALL) still suffer from recurrent disease. Especially patients with an early relapse occurring before 6 months of treatment cessation have a poor prognosis and, therefore, urgently need therapy optimization. As an initial step, detection of genetic aberrations that are associated with resistant disease and/or early relapse might be of great value as they could serve as prognostic markers to predict disease recurrence and, in addition, may increase our understanding of mechanisms underlying treatment resistance and early relapse. This knowledge may also help to identify new therapeutic strategies including targeted approaches. Surprisingly, almost no information is available on the genetic evolution from initial diagnosis to early relapse. As a first aim in the process of uncovering the pathomechanism of early relapse we wanted to find out if early relapse of childhood ALL reflects primarily resistant disease with little or no additional aberrations at relapse or represents evolution and selection of a new and more resistant clone possibly triggered through chemotherapy. Recently, high throughput technologies (single nucleotide polymorphism [SNP]–Arrays) have been developed to screen the whole genome with high resolution for submicroscopic, genetic alterations by simultaneously analyzing the SNP genotype and determining the copy number state. This prompted us to perform SNP-array analysis encompassing more than 100.000 SNPs in 20 childhood ALL samples collected at initial diagnosis and to compare them to their counterparts obtained at relapse. The analyzed patients belonged to the intermediate or high risk treatment group; 16 exhibited B-precursor and 4 T-precursor ALL. Exclusion criteria were translocations t(12;21), t(9;22) and (4;11) as well as pre-existing conditions (e.g. Down syndrome). At initial diagnosis, the leukemic sample of all patients already displayed a complex karyotype with multiple genetic lesions (average numbers per patient: 5.15 deletions, 1.35 amplifications, and 0.65 copy number neutral LOH (CNN-LOH)). Most alterations remained stable from initial diagnosis to relapse (99 of 103 (96%) initially observed deletions as well as 24 of 27 (89%) amplifications). Four deletions occurring in 3 different patients at initial diagnosis disappeared at relapse. Nevertheless, these patients had additional stable copy number alterations. Newly occurring aberrations at relapse were less frequent (average numbers per patient: 1.8 new deletions, 0.75 new amplifications, and 0.15 new CNN-LOH). In 3 patients genetic alterations at diagnosis and relapse were entirely identical. The most commonly affected chromosome was 9p (75% of samples). Fourteen patients had either heterozygous or homozygous deletions of CDKN2A at initial diagnosis and relapse with 2 patients progressing from heterozygous to homozygous deletions. PAX5 deletions (mainly heterozygous) were detectable in 9 patients at initial diagnosis and 10 patients at relapse. Other sides of recurrent deletions – mainly detected at relapse – included multiple areas of chromosome 7p (p21.3, p15.3, p14.3, p14.3-14.1, p14.1-p13) as well as chromosome 1q (deletion: q42.12-q44, amplification: q25.2-q31.1), chromosome 17p (deletion: p13.3-p11.2) and 17q (amplification: q21.2-q25.1). Potential pathogenetic implications of specific recurrent genetic lesions will be discussed. In conclusion, our results demonstrate a high degree of genomic stability from initial diagnosis to early relapse of childhood ALL. These results suggest that – at least in some patients – early relapse might already be predetermined by a resistant leukemic clone at the time of initial diagnosis.