RESUMO
ABSTRACT: Allogeneic stem cell transplantation (alloSCT) is a curative treatment for hematological malignancies. After HLA-matched alloSCT, antitumor immunity is caused by donor T cells recognizing polymorphic peptides, designated minor histocompatibility antigens (MiHAs), that are presented by HLA on malignant patient cells. However, T cells often target MiHAs on healthy nonhematopoietic tissues of patients, thereby inducing side effects known as graft-versus-host disease. Here, we aimed to identify the dominant repertoire of HLA-I-restricted MiHAs to enable strategies to predict, monitor or modulate immune responses after alloSCT. To systematically identify novel MiHAs by genome-wide association screening, T-cell clones were isolated from 39 transplanted patients and tested for reactivity against 191 Epstein-Barr virus transformed B cell lines of the 1000 Genomes Project. By discovering 81 new MiHAs, we more than doubled the antigen repertoire to 159 MiHAs and demonstrated that, despite many genetic differences between patients and donors, often the same MiHAs are targeted in multiple patients. Furthermore, we showed that one quarter of the antigens are cryptic, that is translated from unconventional open reading frames, for example long noncoding RNAs, showing that these antigen types are relevant targets in natural immune responses. Finally, using single cell RNA-seq data, we analyzed tissue expression of MiHA-encoding genes to explore their potential role in clinical outcome, and characterized 11 new hematopoietic-restricted MiHAs as potential targets for immunotherapy. In conclusion, we expanded the repertoire of HLA-I-restricted MiHAs and identified recurrent, cryptic and hematopoietic-restricted antigens, which are fundamental to predict, follow or manipulate immune responses to improve clinical outcome after alloSCT.
Assuntos
Transplante de Células-Tronco Hematopoéticas , Antígenos de Histocompatibilidade Classe I , Antígenos de Histocompatibilidade Menor , Humanos , Antígenos de Histocompatibilidade Menor/genética , Antígenos de Histocompatibilidade Menor/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/genética , Neoplasias Hematológicas/imunologia , Neoplasias Hematológicas/terapia , Neoplasias Hematológicas/genética , Linfócitos T/imunologia , Estudo de Associação Genômica Ampla , Transplante Homólogo , Feminino , MasculinoRESUMO
Diffuse large B cell lymphoma of activated B cell type (ABC-DLBCL), a major cell-of-origin DLBCL subtype, is characterized by chronic active B cell receptor (BCR) signaling and NF-κB activation, which can be explained by activating mutations of the BCR signaling cascade in a minority of cases. We demonstrate that autonomous BCR signaling, akin to its essential pathogenetic role in chronic lymphocytic leukemia (CLL), can explain chronic active BCR signaling in ABC-DLBCL. 13 of 18 tested DLBCL-derived BCR, including 12 cases selected for expression of IgM, induced spontaneous calcium flux and increased phosphorylation of the BCR signaling cascade in murine triple knockout pre-B cells without antigenic stimulation or external BCR crosslinking. Autonomous BCR signaling was associated with IgM isotype, dependent on somatic BCR mutations and individual HCDR3 sequences, and largely restricted to non-GCB DLBCL. Autonomous BCR signaling represents a novel immunological oncogenic driver mechanism in DLBCL originating from individual BCR sequences and adds a new dimension to currently proposed genetics- and transcriptomics-based DLBCL classifications.
Assuntos
Leucemia Linfocítica Crônica de Células B , Linfoma Difuso de Grandes Células B , Animais , Camundongos , Linfócitos B , Linfoma Difuso de Grandes Células B/genética , Receptores de Antígenos de Linfócitos B , Imunoglobulina MRESUMO
Clonal expansion of CD5-expressing B cells, commonly designated as monoclonal B lymphocytosis (MBL), is a precursor condition for chronic lymphocytic leukemia (CLL). The mechanisms driving subclinical MBL B-cell expansion and progression to CLL, occurring in approximately 1% of affected individuals, are unknown. An autonomously signaling B-cell receptor (BCR) is essential for the pathogenesis of CLL. The objectives of this study were functional characterization of the BCR of MBL in siblings of CLL patients and a comparison of genetic variants in MBL-CLL sibling pairs. Screening of peripheral blood by flow cytometry detected 0.2-480 clonal CLL-phenotype cells per microliter (median: 37/µL) in 34 of 191 (17.8%) siblings of CLL patients. Clonal BCR isolated from highly purified CLL-phenotype cells induced robust calcium mobilization in BCR-deficient murine pre-B cells in the absence of external antigen and without experimental crosslinking. This autonomous BCR signal was less intense than the signal originating from the CLL BCR of their CLL siblings. According to genotyping by single nucleotide polymorphism array, whole exome, and targeted panel sequencing, CLL risk alleles were found with high and similar prevalence in CLL patients and MBL siblings, respectively. Likewise, the prevalence of recurrent CLL-associated genetic variants was similar between CLL and matched MBL samples. However, copy number variations and small variants were frequently subclonal in MBL cells, suggesting their acquisition during subclinical clonal expansion. These findings support a stepwise model of CLL pathogenesis, in which autonomous BCR signaling leads to a non-malignant (oligo)clonal expansion of CD5+ B cells, followed by malignant progression to CLL after acquisition of pathogenic genetic variants.
Assuntos
Leucemia Linfocítica Crônica de Células B , Leucemia , Linfocitose , Humanos , Animais , Camundongos , Leucemia Linfocítica Crônica de Células B/genética , Irmãos , Variações do Número de Cópias de DNA , Linfocitose/genética , Receptores de Antígenos de Linfócitos B/genética , FenótipoRESUMO
Cancers evade T-cell immunity by several mechanisms such as secretion of anti-inflammatory cytokines, down regulation of antigen presentation machinery, upregulation of immune checkpoint molecules, and exclusion of T cells from tumor tissues. The distribution and function of immune checkpoint molecules on tumor cells and tumor-infiltrating leukocytes is well established, but less is known about their impact on intratumoral endothelial cells. Here, we demonstrated that V-domain Ig suppressor of T-cell activation (VISTA), a PD-L1 homolog, was highly expressed on endothelial cells in synovial sarcoma, subsets of different carcinomas, and immune-privileged tissues. We created an ex vivo model of the human vasculature and demonstrated that expression of VISTA on endothelial cells selectively prevented T-cell transmigration over endothelial layers under physiologic flow conditions, whereas it does not affect migration of other immune cell types. Furthermore, endothelial VISTA correlated with reduced infiltration of T cells and poor prognosis in metastatic synovial sarcoma. In endothelial cells, we detected VISTA on the plasma membrane and in recycling endosomes, and its expression was upregulated by cancer cell-secreted factors in a VEGF-A-dependent manner. Our study reveals that endothelial VISTA is upregulated by cancer-secreted factors and that it regulates T-cell accessibility to cancer and healthy tissues. This newly identified mechanism should be considered when using immunotherapeutic approaches aimed at unleashing T cell-mediated cancer immunity.
Assuntos
Antígenos B7 , Sarcoma Sinovial , Humanos , Células Endoteliais/metabolismo , Endotélio/metabolismo , Proteínas de Checkpoint Imunológico , Linfócitos TRESUMO
Activation-induced deaminase (AID) is required for somatic hypermutation in immunoglobulin genes, but also induces off-target mutations. Follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL), the most frequent types of indolent B-cell tumors, are exposed to AID activity during lymphomagenesis. We designed a workflow integrating de novo mutational signatures extraction and fitting of COSMIC (Catalogue Of Somatic Mutations In Cancer) signatures, with tridimensional chromatin conformation data (Hi-C). We applied the workflow to exome sequencing data from lymphoma samples. In 33 FL and 30 CLL samples, 42% and 34% of the contextual mutations could be traced to a known AID motif. We demonstrate that both CLL and FL share mutational processes dominated by spontaneous deamination, failures in DNA repair, and AID activity. The processes had equiproportional distribution across active and nonactive chromatin compartments in CLL. In contrast, canonical AID activity and failures in DNA repair pathways in FL were significantly higher within the active chromatin compartment. Analysis of DNA repair genes revealed a higher prevalence of base excision repair gene mutations (p = 0.02) in FL than CLL. These data indicate that AID activity drives the genetic landscapes of FL and CLL. However, the final result of AID-induced mutagenesis differs between these lymphomas depending on chromatin compartmentalization and mutations in DNA repair pathways.
Assuntos
Citidina Desaminase/genética , Leucemia Linfocítica Crônica de Células B/patologia , Linfoma Folicular/patologia , Alelos , Cromatina/metabolismo , Análise Mutacional de DNA , Reparo do DNA/genética , Bases de Dados Genéticas , Frequência do Gene , Humanos , Leucemia Linfocítica Crônica de Células B/genética , Linfoma Folicular/genética , Polimorfismo de Nucleotídeo ÚnicoRESUMO
BACKGROUND: Drawing genotype-to-phenotype maps in tumors is of paramount importance for understanding tumor heterogeneity. Assignment of single cells to their tumor clones of origin can be approached by matching the genotypes of the clones to the mutations found in RNA sequencing of the cells. The confidence of the cell-to-clone mapping can be increased by accounting for additional measurements. Follicular lymphoma, a malignancy of mature B cells that continuously acquire mutations in parallel in the exome and in B cell receptor loci, presents a unique opportunity to join exome-derived mutations with B cell receptor sequences as independent sources of evidence for clonal evolution. METHODS: Here, we propose CACTUS, a probabilistic model that leverages the information from an independent genomic clustering of cells and exploits the scarce single cell RNA sequencing data to map single cells to given imperfect genotypes of tumor clones. RESULTS: We apply CACTUS to two follicular lymphoma patient samples, integrating three measurements: whole exome, single-cell RNA, and B cell receptor sequencing. CACTUS outperforms a predecessor model by confidently assigning cells and B cell receptor-based clusters to the tumor clones. CONCLUSIONS: The integration of independent measurements increases model certainty and is the key to improving model performance in the challenging task of charting the genotype-to-phenotype maps in tumors. CACTUS opens the avenue to study the functional implications of tumor heterogeneity, and origins of resistance to targeted therapies. CACTUS is written in R and source code, along with all supporting files, are available on GitHub ( https://github.com/LUMC/CACTUS ).
Assuntos
Perfilação da Expressão Gênica , Genômica , Neoplasias/genética , Análise de Célula Única , Software , Células Clonais , Análise por Conglomerados , Regulação Neoplásica da Expressão Gênica , Humanos , Linfoma Folicular/genética , Modelos Estatísticos , Reprodutibilidade dos Testes , Sequenciamento do ExomaRESUMO
Acute myeloid leukemia (AML) is caused by genetic aberrations that also govern the prognosis of patients and guide risk-adapted and targeted therapy. Genetic aberrations in AML are structurally diverse and currently detected by different diagnostic assays. This study sought to establish whole transcriptome RNA sequencing as single, comprehensive, and flexible platform for AML diagnostics. We developed HAMLET (Human AML Expedited Transcriptomics) as bioinformatics pipeline for simultaneous detection of fusion genes, small variants, tandem duplications, and gene expression with all information assembled in an annotated, user-friendly output file. Whole transcriptome RNA sequencing was performed on 100 AML cases and HAMLET results were validated by reference assays and targeted resequencing. The data showed that HAMLET accurately detected all fusion genes and overexpression of EVI1 irrespective of 3q26 aberrations. In addition, small variants in 13 genes that are often mutated in AML were called with 99.2% sensitivity and 100% specificity, and tandem duplications in FLT3 and KMT2A were detected by a novel algorithm based on soft-clipped reads with 100% sensitivity and 97.1% specificity. In conclusion, HAMLET has the potential to provide accurate comprehensive diagnostic information relevant for AML classification, risk assessment and targeted therapy on a single technology platform.
Assuntos
Sequenciamento do Exoma , Perfilação da Expressão Gênica , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Transcriptoma , Biomarcadores Tumorais , Biologia Computacional/métodos , Feminino , Perfilação da Expressão Gênica/métodos , Regulação Leucêmica da Expressão Gênica , Variação Genética , Genômica/métodos , Humanos , Masculino , Técnicas de Diagnóstico Molecular , Mutação , Proteínas de Fusão Oncogênica , Prognóstico , Reprodutibilidade dos Testes , Sequenciamento do Exoma/métodosRESUMO
Patients undergoing allogeneic stem cell transplantation as treatment for hematological diseases face the risk of Graft-versus-Host Disease as well as relapse. Graft-versus-Host Disease and the favorable Graft-versus-Leukemia effect are mediated by donor T cells recognizing polymorphic peptides, which are presented on the cell surface by HLA molecules and result from single nucleotide polymorphism alleles that are disparate between patient and donor. Identification of polymorphic HLA-binding peptides, designated minor histocompatibility antigens, has been a laborious procedure, and the number and scope for broad clinical use of these antigens therefore remain limited. Here, we present an optimized whole genome association approach for discovery of HLA class I minor histocompatibility antigens. T cell clones isolated from patients who responded to donor lymphocyte infusions after HLA-matched allogeneic stem cell transplantation were tested against a panel of 191 EBV-transformed B cells, which have been sequenced by the 1000 Genomes Project and selected for expression of seven common HLA class I alleles (HLA-A∗01:01, A∗02:01, A∗03:01, B∗07:02, B∗08:01, C∗07:01, and C∗07:02). By including all polymorphisms with minor allele frequencies above 0.01, we demonstrated that the new approach allows direct discovery of minor histocompatibility antigens as exemplified by seven new antigens in eight different HLA class I alleles including one antigen in HLA-A∗24:02 and HLA-A∗23:01, for which the method has not been originally designed. Our new whole genome association strategy is expected to rapidly augment the repertoire of HLA class I-restricted minor histocompatibility antigens that will become available for donor selection and clinical use to predict, follow or manipulate Graft-versus-Leukemia effect and Graft-versus-Host Disease after allogeneic stem cell transplantation.
Assuntos
Doença Enxerto-Hospedeiro/imunologia , Efeito Enxerto vs Leucemia/imunologia , Antígenos de Histocompatibilidade Menor/metabolismo , Transplante de Células-Tronco , Linfócitos T/imunologia , Alelos , Células Clonais , Estudo de Associação Genômica Ampla , Doença Enxerto-Hospedeiro/genética , Efeito Enxerto vs Leucemia/genética , Antígenos HLA-A/genética , Antígenos HLA-A/metabolismo , Antígenos HLA-B/genética , Antígenos HLA-B/metabolismo , Antígenos HLA-C/genética , Antígenos HLA-C/metabolismo , Humanos , Antígenos de Histocompatibilidade Menor/genética , Antígenos de Histocompatibilidade Menor/imunologia , Polimorfismo de Nucleotídeo Único , Ligação Proteica , Transplante HomólogoRESUMO
Minor histocompatibility antigens are the main targets of donor-derived T-cells after allogeneic stem cell transplantation. Identification of these antigens and understanding their biology are a key requisite for more insight into how graft vs. leukemia effect and graft vs. host disease could be separated. We here identified four new HLA class II-restricted minor histocompatibility antigens using whole genome association scanning. For one of the new antigens, i.e., LB-PIP4K2A-1S, we measured strong T-cell recognition of the donor variant PIP4K2A-1N when pulsed as exogenous peptide, while the endogenously expressed variant in donor EBV-B cells was not recognized. We showed that lack of T-cell recognition was caused by intracellular cleavage by a protease named asparagine endopeptidase (AEP). Furthermore, microarray gene expression analysis showed that PIP4K2A and AEP are both ubiquitously expressed in a wide variety of healthy tissues, but that expression levels of AEP were lower in primary acute myeloid leukemia (AML). In line with that, we confirmed low activity of AEP in AML cells and demonstrated that HLA-DRB1*03:01 positive primary AML expressing LB-PIP4K2A-1S or its donor variant PIP4K2A-1N were both recognized by specific T-cells. In conclusion, LB-PIP4K2A-1S not only represents a novel minor histocompatibility antigen but also provides evidence that donor T-cells after allogeneic stem cell transplantation can target the autologous allelic variant as leukemia-associated antigen. Furthermore, it demonstrates that endopeptidases can play a role in cell type-specific intracellular processing and presentation of HLA class II-restricted antigens, which may be explored in future immunotherapy of AML.
Assuntos
Cisteína Endopeptidases/metabolismo , Leucemia Mieloide Aguda , Antígenos de Histocompatibilidade Menor , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Variação Genética , Efeito Enxerto vs Leucemia/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/imunologia , Leucemia Mieloide Aguda/metabolismo , Antígenos de Histocompatibilidade Menor/genética , Antígenos de Histocompatibilidade Menor/imunologia , Antígenos de Histocompatibilidade Menor/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/imunologia , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismoRESUMO
The prognosis of chronic lymphocytic leukemia (CLL) depends on different markers, including cytogenetic aberrations, oncogenic mutations, and mutational status of the immunoglobulin (Ig) heavy-chain variable (IGHV) gene. The number of IGHV mutations distinguishes mutated (M) CLL with a markedly superior prognosis from unmutated (UM) CLL cases. In addition, B cell antigen receptor (BCR) stereotypes as defined by IGHV usage and complementarity-determining regions (CDRs) classify â¼30% of CLL cases into prognostically important subsets. Subset 2 expresses a BCR with the combination of IGHV3-21-derived heavy chains (HCs) with IGLV3-21-derived light chains (LCs), and is associated with an unfavorable prognosis. Importantly, the subset 2 LC carries a single-point mutation, termed R110, at the junction between the variable and constant LC regions. By analyzing 4 independent clinical cohorts through BCR sequencing and by immunophenotyping with antibodies specifically recognizing wild-type IGLV3-21 and R110-mutated IGLV3-21 (IGLV3-21R110), we show that IGLV3-21R110-expressing CLL represents a distinct subset with poor prognosis independent of IGHV mutations. Compared with other alleles, only IGLV3-21*01 facilitates effective homotypic BCR-BCR interaction that results in autonomous, oncogenic BCR signaling after acquiring R110 as a single-point mutation. Presumably, this mutation acts as a standalone driver that transforms IGLV3-21*01-expressing B cells to develop CLL. Thus, we propose to expand the conventional definition of CLL subset 2 to subset 2L by including all IGLV3-21R110-expressing CLL cases regardless of IGHV mutational status. Moreover, the generation of monoclonal antibodies recognizing IGLV3-21 or mutated IGLV3-21R110 facilitates the recognition of B cells carrying this mutation in CLL patients or healthy donors.
Assuntos
Cadeias lambda de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/genética , Receptores de Antígenos de Linfócitos B/imunologia , Linfócitos B/imunologia , Estudos de Coortes , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/imunologia , Predisposição Genética para Doença , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Pesadas de Imunoglobulinas/imunologia , Cadeias lambda de Imunoglobulina/imunologia , Leucemia Linfocítica Crônica de Células B/imunologia , Mutação Puntual , Receptores de Antígenos de Linfócitos B/genéticaRESUMO
Primary cutaneous follicle center lymphoma (PCFCL) is a rare mature B-cell lymphoma with an unknown etiology. PCFCL resembles follicular lymphoma (FL) by cytomorphologic and microarchitectural criteria. FL B cells are selected for N-linked glycosylation motifs in their B-cell receptors (BCRs) that are acquired during continuous somatic hypermutation. The stimulation of mannosylated BCR by lectins on the tumor microenvironment is therefore a candidate driver in FL pathogenesis. We investigated whether the same mechanism could play a role in PCFCL pathogenesis. Full-length functional variable, diversity, and joining gene sequences of 18 PCFCL and 8 primary cutaneous diffuse large B-cell lymphoma, leg-type were identified by unbiased Anchoring Reverse Transcription of Immunoglobulin Sequences and Amplification by Nested PCR and BCR reconstruction from RNA sequencing data. Low BCR variation demonstrated negligible ongoing somatic hypermutation in PCFCL and primary cutaneous diffuse large B-cell lymphoma, leg-type, and indicated that the PCFCL microarchitecture does not act as a functional germinal center. Similar to FL but in contrast to primary cutaneous diffuse large B-cell lymphoma, leg-type, BCR genes of 15 PCFCLs (83%) had acquired N-linked glycosylation motifs. These motifs were located at the BCR positions converted to N-linked glycosylation motifs in normal B-cell repertoires with low prevalence but mostly at different positions than those found in FL. The cutaneous localization of PCFCL might suggest a role for lectins from commensal skin bacteria in PCFCL lymphomagenesis.
Assuntos
Regulação da Expressão Gênica , Linfoma Folicular/genética , Linfoma Folicular/patologia , Linfoma Difuso de Grandes Células B/genética , Receptores de Antígenos de Linfócitos B/genética , Neoplasias Cutâneas/genética , Idoso , Idoso de 80 Anos ou mais , Biópsia por Agulha , Estudos de Coortes , Análise Mutacional de DNA , Diagnóstico Diferencial , Feminino , Centro Germinativo/metabolismo , Glicosilação , Humanos , Imuno-Histoquímica , Linfoma Difuso de Grandes Células B/patologia , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Prognóstico , Neoplasias Cutâneas/patologia , Microambiente Tumoral/genéticaRESUMO
MHC-bound peptides from aberrant proteins may be a specific immunotherapeutic target on cancer cells. Because of difficulties in identifying such antigens, viral or model antigens have so far been used to study their biological relevance. We here identify a naturally existing human T-cell epitope derived from a truncated protein. The antigenic peptide is derived from the gene TTK only through an alternative transcript containing a premature termination codon that may target the transcript for nonsense-mediated decay (NMD). This antigen is recognized by HLA-A*02:01-restricted CD8+ T cells derived from an allotransplanted leukemia patient. Functional analyses showed that these T cells failed to recognize several HLA-matched primary leukemic cells that expressed the alternative TTK transcript. Conventional antigen processing and presentation were not affected, suggesting that leukemic cells modify the generation of antigens processed from aberrant proteins. This natural TTK epitope provides insights in the source of transcripts producing antigenic epitopes in healthy and leukemic cells. Our data underscore potential pitfalls of targeting NMD-derived or other unconventionally generated epitopes as immunotherapeutic approach.
Assuntos
Epitopos de Linfócito T/imunologia , Leucemia/imunologia , Linfócitos T Citotóxicos/imunologia , HumanosRESUMO
Under non-inflammatory conditions HLA class II is predominantly expressed on hematopoietic cells. Therefore, donor CD4 T-cells after allogeneic stem cell transplantation (alloSCT) may mediate graft-vs.-leukemia reactivity without graft-vs.-host disease (GVHD). We analyzed immune responses in four patients converting from mixed to full donor chimerism without developing GVHD upon purified CD4 donor lymphocyte infusion (DLI) from their HLA-identical sibling donor after T-cell depleted alloSCT. In vivo activated T-cells were clonally isolated after CD4 DLI. Of the alloreactive T-cell clones, 96% were CD4 positive, illustrating the dominant role of CD4 T-cells in the immune responses. We identified 9 minor histocompatibility antigens (MiHA) as targets for alloreactivity, of which 8 were novel HLA class II restricted MiHA. In all patients, MiHA specific CD4 T-cells were found that were capable to lyse hematopoietic cells and to recognize normal and malignant cells. No GVHD was induced in these patients. Skin fibroblasts forced to express HLA class II, were recognized by only two MiHA specific CD4 T-cell clones. Of the 7 clones that failed to recognize fibroblasts, two targeted MiHA were encoded by genes not expressed in fibroblasts, presentation of one MiHA was dependent on HLA-DO, which is absent in fibroblasts, and T-cells recognizing the remaining 4 MiHA had an avidity that was apparently too low to recognize fibroblasts, despite clear recognition of hematopoietic cells. In conclusion, purified CD4 DLI from HLA-identical sibling donors can induce conversion from mixed to full donor chimerism with graft-vs.-malignancy reactivity, but without GVHD, by targeting HLA class II restricted MiHA.
Assuntos
Linfócitos T CD4-Positivos/transplante , Doença Enxerto-Hospedeiro/prevenção & controle , Leucemia/terapia , Transplante de Células-Tronco de Sangue Periférico/efeitos adversos , Condicionamento Pré-Transplante/métodos , Linfócitos T CD4-Positivos/imunologia , Quimerismo , Feminino , Doença Enxerto-Hospedeiro/imunologia , Efeito Enxerto vs Leucemia/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Doadores Vivos , Masculino , Pessoa de Meia-Idade , Antígenos de Histocompatibilidade Menor/imunologia , Agonistas Mieloablativos/uso terapêutico , Irmãos , Transplante Homólogo , Resultado do TratamentoRESUMO
BACKGROUND: Donors for allogeneic stem cell transplantation are preferentially matched with patients for HLA-A, -B, -C, and -DRB1. Mismatches between donor and patient in these alleles are associated with an increased risk of graft-versus-host disease (GVHD). In contrast, HLA-DRB3, 4 and 5, HLA-DQ and HLA-DP are usually assumed to be low expression loci with limited relevance, although mismatches in HLA-DQ and HLA-DP can result in alloimmune responses. Mismatches in HLA-DRB3, 4, and 5 are usually not taken into account in donor selection. METHODS: Conversion of chimerism in the presence of GVHD after CD4 donor lymphocyte infusion was observed in a patient, HLA 10/10 matched, but mismatched for HLA-DRB3 and HLA-DPB1 compared with the donor. Alloreactive CD4 T cells were isolated from peripheral blood after CD4 donor lymphocyte infusion and recognition of donor-derived target cells transduced with the mismatched patient variant HLA-DRB3 and HLA-DPB1 molecule was tested. RESULTS: A dominant polyclonal CD4 T cell response against patient's mismatched HLA-DRB3 molecule was found in addition to an immune response against patient's mismatched HLA-DPB1 molecule. CD4 T cells specific for these HLA class II molecules recognized both hematopoietic target cells as well as GVHD target cells. CONCLUSIONS: In contrast to the assumption that mismatches in HLA-DRB3, 4, and 5 are not of immunogenic significance after HLA 10/10 matched allogeneic stem cell transplantation, we show that in this matched setting not only mismatches in HLA-DPB1, but also mismatches in HLA-DRB3 may induce a polyclonal allo-immune response associated with conversion of chimerism and severe GVHD.
Assuntos
Antígenos HLA/imunologia , Cadeias HLA-DRB3/imunologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/imunologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Transplante de Células-Tronco , Linfócitos T/imunologia , Alelos , Incompatibilidade de Grupos Sanguíneos , Linfócitos T CD4-Positivos/imunologia , Quimerismo , Doença Enxerto-Hospedeiro/imunologia , Antígenos HLA-DP/imunologia , Antígenos HLA-DQ/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Indução de Remissão , Doadores de Tecidos , Transplante Homólogo , Resultado do TratamentoRESUMO
Patients with leukemia who receive a T cell-depleted allogeneic stem cell graft followed by postponed donor lymphocyte infusion (DLI) can experience graft-versus-leukemia (GVL) reactivity, with a lower risk of graft-versus-host disease (GVHD). Here, we have investigated the magnitude, diversity, and specificity of alloreactive CD8 T cells in patients who developed GVL reactivity after DLI in the absence or presence of GVHD. We observed a lower magnitude and diversity of CD8 T cells for minor histocompatibility antigens (MiHAs) in patients with selective GVL reactivity without GVHD. Furthermore, we demonstrated that MiHA-specific T cell clones from patients with selective GVL reactivity showed lower reactivity against nonhematopoietic cells, even when pretreated with inflammatory cytokines. Expression analysis of MiHA-encoding genes showed that similar types of antigens were recognized in both patient groups, but in patients who developed GVHD, T cell reactivity was skewed to target broadly expressed MiHAs. As an inflammatory environment can render nonhematopoietic cells susceptible to T cell recognition, prevention of such circumstances favors induction of selective GVL reactivity without development of GVHD.
Assuntos
Antígenos de Neoplasias/imunologia , Linfócitos T CD8-Positivos/imunologia , Efeito Enxerto vs Leucemia/imunologia , Leucemia/imunologia , Antígenos de Histocompatibilidade Menor/imunologia , Antígenos de Neoplasias/genética , Feminino , Doença Enxerto-Hospedeiro/genética , Doença Enxerto-Hospedeiro/imunologia , Efeito Enxerto vs Leucemia/genética , Humanos , Leucemia/genética , Leucemia/terapia , Masculino , Antígenos de Histocompatibilidade Menor/genéticaRESUMO
Although double umbilical cord blood transplantation (dUCBT) in adult patients may be associated with less graft failure compared with single UCBT, hematopoietic recovery generally originates from a single cord blood unit (CBU). CBU predominance is still incompletely understood. We recently showed that blood CD4+ T-cell numbers rapidly increase after dUCBT, and early CD4+ T-cell chimerism predicts for graft predominance. Given the frequent HLA class II allele mismatches between CBUs in dUCBT, we hypothesized that alloreactive HLA class II-specific CD4+ T cells from the "winning" CBU may contribute to rejection of the "loser" CBU. We evaluated whether CD4+ T cells originating from the predominant (PD)-CBU would recognize HLA class II allele mismatches, expressed by the nonengrafting (NE)-CBU. Alloreactive effector CD4+ T cells toward 1 or more mismatched HLA class II alleles of the NE-CBU were detected in 11 of 11 patients, with reactivity toward 29 of 33 (88%) tested mismatches, and the strongest reactivity toward DR and DQ alleles early after dUCBT. Mismatched HLA class II allele-specific CD4+ T cells recognized primary leukemic cells when the mismatched HLA class II allele was shared between NE-CBU and patient. Our results suggest that cytotoxicity exerted by CD4+ T cells from the PD-CBU drives the rapid rejection of the NE-CBU, whose alloreactive effect might also contribute to graft-versus-leukemia.
Assuntos
Aloenxertos/imunologia , Linfócitos T CD4-Positivos/imunologia , Transplante de Células-Tronco de Sangue do Cordão Umbilical/métodos , Efeito Enxerto vs Leucemia/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Adulto , Alelos , Anemia Aplástica/terapia , Animais , Quimerismo , Feminino , Citometria de Fluxo , Humanos , Leucemia/terapia , Linfoma não Hodgkin/terapia , Masculino , Pessoa de Meia-IdadeRESUMO
PURPOSE: In HLA-matched allogeneic hematopoietic stem cell transplantation (alloSCT), donor T cells recognizing minor histocompatibility antigens (MiHAs) can mediate desired antitumor immunity as well as undesired side effects. MiHAs with hematopoiesis-restricted expression are relevant targets to augment antitumor immunity after alloSCT without side effects. To identify therapeutic MiHAs, we analyzed the in vivo immune response in a patient with strong antitumor immunity after alloSCT. EXPERIMENTAL DESIGN: T-cell clones recognizing patient, but not donor, hematopoietic cells were selected for MiHA discovery by whole genome association scanning. RNA-sequence data from the GEUVADIS project were analyzed to investigate alternative transcripts, and expression patterns were determined by microarray analysis and qPCR. T-cell reactivity was measured by cytokine release and cytotoxicity. RESULTS: T-cell clones were isolated for two HLA-B*15:01-restricted MiHA. LB-GLE1-1V is encoded by a nonsynonymous SNP in exon 6 of GLE1 For the other MiHAs, an associating SNP in intron 3 of ITGB2 was found, but no SNP disparity was present in the normal gene transcript between patient and donor. RNA-sequence analysis identified an alternative ITGB2 transcript containing part of intron 3. qPCR demonstrated that this transcript is restricted to hematopoietic cells and SNP-positive individuals. In silico translation revealed LB-ITGB2-1 as HLA-B*15:01-binding peptide, which was validated as hematopoietic MiHA by T-cell experiments. CONCLUSIONS: Whole genome and transcriptome analysis identified LB-ITGB2-1 as MiHAs encoded by an alternative transcript. Our data support the therapeutic relevance of LB-ITGB2-1 and illustrate the value of RNA-sequence analysis for discovery of immune targets encoded by alternative transcripts. Clin Cancer Res; 22(16); 4185-96. ©2016 AACR.
Assuntos
Processamento Alternativo , Perfilação da Expressão Gênica , Integrina beta3/genética , Antígenos de Histocompatibilidade Menor/genética , Sequenciamento Completo do Genoma , Sequência de Aminoácidos , Sequência de Bases , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Feminino , Antígeno HLA-B15/genética , Antígeno HLA-B15/imunologia , Transplante de Células-Tronco Hematopoéticas , Humanos , Integrina beta3/química , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/imunologia , Antígenos de Histocompatibilidade Menor/química , Antígenos de Histocompatibilidade Menor/imunologia , Peptídeos/genética , Peptídeos/imunologia , Linfócitos T , Transplante HomólogoRESUMO
Allogeneic stem cell transplantation (alloSCT) can be a curative treatment for hematological malignancies. Unfortunately, the desired anti-tumor or graft-versus-leukemia (GvL) effect is often accompanied with undesired side effects against healthy tissues known as graft-versus-host disease (GvHD). After HLA-matched alloSCT, GvL and GvHD are both mediated by donor-derived T-cells recognizing polymorphic peptides presented by HLA surface molecules on patient cells. These polymorphic peptides or minor histocompatibility antigens (MiHA) are produced by genetic differences between patient and donor. Since polymorphic peptides may be useful targets to manipulate the balance between GvL and GvHD, the dominant repertoire of MiHA needs to be discovered. In this review, the diversity of autosomal MiHA characterized thus far as well as the various molecular mechanisms by which genetic variants create immune targets and the role of cryptic transcripts and proteins as antigen sources are described. The tissue distribution of MiHA as important factor in GvL and GvHD is considered as well as possibilities how hematopoietic MiHA can be used for immunotherapy to augment GvL after alloSCT. Although more MiHA are still needed for comprehensive understanding of the biology of GvL and GvHD and manipulation by immunotherapy, this review shows insight into the composition and kinetics of in vivo immune responses with respect to specificity, diversity, and frequency of specific T-cells and surface expression of HLA-peptide complexes and other (accessory) molecules on the target cell. A complex interplay between these factors and their environment ultimately determines the spectrum of clinical manifestations caused by immune responses after alloSCT.