RESUMO
Fanconi anemia (FA) has long been considered a severe inherited bone marrow failure (BMF) disorder of early childhood. Thus, management of this multisystem disorder has previously been unfamiliar to many hematologists specializing in the care of adolescents and young adults (AYA). The increased diagnosis of FA in AYA patients, facilitated by widely available germline genomic testing, improved long-term survival of children with FA following matched sibling and alternative donor hematopoietic stem cell transplantation (HSCT) performed for BMF, and expanding need in the near future for long-term monitoring in patients achieving hematologic stabilization following ex vivo gene therapy are all reasons why management of FA in AYA populations deserves specific consideration. In this review, we address the unique challenges and evidence-based practice recommendations for the management of AYA patients with FA. Specific topics addressed include hematologic monitoring in AYA patients yet to undergo HSCT, management of myeloid malignancies occurring in FA, diagnosis and management of nonhematologic malignances and organ dysfunction in AYA patients with FA, and evolving considerations for the long-term monitoring of patients with FA undergoing gene therapy.
Assuntos
Anemia de Fanconi , Transplante de Células-Tronco Hematopoéticas , Adolescente , Humanos , Adulto Jovem , Transtornos da Insuficiência da Medula Óssea , Anemia de Fanconi/diagnóstico , Anemia de Fanconi/genética , Anemia de Fanconi/terapia , Terapia GenéticaRESUMO
Hematopoietic stem cell transplantation (HSCT) remains the only curative treatment for a variety of hematological diseases. Allogenic HSCT requires hematopoietic stem cells (HSCs) from matched donors and comes with cytotoxicity and mortality. Recent advances in genome modification of HSCs have demonstrated the possibility of using autologous HSCT-based gene therapy to alleviate hematologic symptoms in monogenic diseases, such as the inherited bone marrow failure (BMF) syndrome Fanconi anemia (FA). However, for FA and other BMF syndromes, insufficient HSC numbers with functional defects results in delayed hematopoietic recovery and increased risk of graft failure. We and others previously identified the adaptor protein LNK (SH2B3) as a critical negative regulator of murine HSC homeostasis. However, whether LNK controls human HSCs has not been studied. Here, we demonstrate that depletion of LNK via lentiviral expression of miR30-based short hairpin RNAs results in robust expansion of transplantable human HSCs that provided balanced multilineage reconstitution in primary and secondary mouse recipients. Importantly, LNK depletion enhances cytokine-mediated JAK/STAT activation in CD34+ hematopoietic stem and progenitor cells (HSPCs). Moreover, we demonstrate that LNK depletion expands primary HSPCs associated with FA. In xenotransplant, engraftment of FANCD2-depleted FA-like HSCs was markedly improved by LNK inhibition. Finally, targeting LNK in primary bone marrow HSPCs from FA patients enhanced their colony forming potential in vitro. Together, these results demonstrate the potential of targeting LNK to expand HSCs to improve HSCT and HSCT-based gene therapy.
Assuntos
Anemia de Fanconi , Transplante de Células-Tronco Hematopoéticas , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Antígenos CD34/metabolismo , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Anemia de Fanconi/terapia , Terapia Genética/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Células-Tronco Hematopoéticas/metabolismo , Humanos , CamundongosRESUMO
Unrelated donor (URD) hematopoietic stem cell transplant (HSCT) is associated with an increased risk of severe graft-versus-host disease (GVHD). TCRαß/CD19 depletion may reduce this risk, whereas maintaining graft-versus-leukemia. Outcome data with TCRαß/CD19 depletion generally describe haploidentical donors, with relatively few URDs. We hypothesized that TCRαß/CD19-depletion would attenuate the risks of GVHD and relapse for URD HSCT. Sixty pediatric and young adult (YA) patients with hematologic malignancies who lacked a matched-related donor were enrolled at 2 large pediatric transplantation centers between October 2014 and September 2019. All patients with acute leukemia had minimal residual disease testing, and DP typing was available for 77%. All patients received myeloablative total body irradiation- or busulfan-based conditioning with no posttransplant immune suppression. Engraftment occurred in 98%. Four-year overall survival was 69% (95% confidence interval [CI], 52%-81%), and leukemia-free survival was 64% (95% CI, 48%-76%), with no difference between lymphoid and myeloid malignancies (P = .6297 and P = .5441, respectively). One patient (1.7%) experienced primary graft failure. Relapse occurred in 11 patients (3-year cumulative incidence, 21%; 95% CI, 11-34), and 8 patients (cumulative incidence, 15%; 95% CI, 6.7-26) experienced nonrelapse mortality. Grade III to IV acute GVHD was seen in 8 patients (13%), and 14 patients (26%) developed chronic GVHD, of which 6 (11%) had extensive disease. Nonpermissive DP mismatch was associated with higher likelihood of acute GVHD (odds ratio, 16.50; 95% CI, 1.67-163.42; P = .0166) but not with the development of chronic GVHD. URD TCRαß/CD19-depleted peripheral HSCT is a safe and effective approach to transplantation for children/YAs with leukemia. This trial was registered at www.clinicaltrials.gov as #NCT02323867.
Assuntos
Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Leucemia Mieloide Aguda , Doença Aguda , Antígenos CD19 , Criança , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Leucemia Mieloide Aguda/terapia , Receptores de Antígenos de Linfócitos T alfa-beta , Recidiva , Linfócitos T , Doadores não Relacionados , Adulto JovemRESUMO
Acquired aplastic anemia (AA) is a life-threatening bone marrow aplasia caused by the autoimmune destruction of hematopoietic stem and progenitor cells. There are no existing diagnostic tests that definitively establish AA, and diagnosis is currently made via systematic exclusion of various alternative etiologies, including inherited bone marrow failure syndromes (IBMFSs). The exclusion of IBMFSs, which requires syndrome-specific functional and genetic testing, can substantially delay treatment. AA and IBMFSs can have mimicking clinical presentations, and their distinction has significant implications for treatment and family planning, making accurate and prompt diagnosis imperative to optimal patient outcomes. We hypothesized that AA could be distinguished from IBMFSs using 3 laboratory findings specific to the autoimmune pathogenesis of AA: paroxysmal nocturnal hemoglobinuria (PNH) clones, copy-number-neutral loss of heterozygosity in chromosome arm 6p (6p CN-LOH), and clonal T-cell receptor (TCR) γ gene (TRG) rearrangement. To test our hypothesis, we determined the prevalence of PNH, acquired 6p CN-LOH, and clonal TRG rearrangement in 454 consecutive pediatric and adult patients diagnosed with AA, IBMFSs, and other hematologic diseases. Our results indicated that PNH and acquired 6p CN-LOH clones encompassing HLA genes have â½100% positive predictive value for AA, and they can facilitate diagnosis in approximately one-half of AA patients. In contrast, clonal TRG rearrangement is not specific for AA. Our analysis demonstrates that PNH and 6p CN-LOH clones effectively distinguish AA from IBMFSs, and both measures should be incorporated early in the diagnostic evaluation of suspected AA using the included Bayesian nomogram to inform clinical application.
Assuntos
Anemia Aplástica , Hemoglobinúria Paroxística , Anemia Aplástica/diagnóstico , Anemia Aplástica/genética , Teorema de Bayes , Criança , Células Clonais , Rearranjo Gênico , Hemoglobinúria Paroxística/diagnóstico , Hemoglobinúria Paroxística/genética , HumanosRESUMO
The pioneer transcription factor (TF) PU.1 controls hematopoietic cell fate by decompacting stem cell heterochromatin and allowing nonpioneer TFs to enter otherwise inaccessible genomic sites. PU.1 deficiency fatally arrests lymphopoiesis and myelopoiesis in mice, but human congenital PU.1 disorders have not previously been described. We studied six unrelated agammaglobulinemic patients, each harboring a heterozygous mutation (four de novo, two unphased) of SPI1, the gene encoding PU.1. Affected patients lacked circulating B cells and possessed few conventional dendritic cells. Introducing disease-similar SPI1 mutations into human hematopoietic stem and progenitor cells impaired early in vitro B cell and myeloid cell differentiation. Patient SPI1 mutations encoded destabilized PU.1 proteins unable to nuclear localize or bind target DNA. In PU.1-haploinsufficient pro-B cell lines, euchromatin was less accessible to nonpioneer TFs critical for B cell development, and gene expression patterns associated with the pro- to pre-B cell transition were undermined. Our findings molecularly describe a novel form of agammaglobulinemia and underscore PU.1's critical, dose-dependent role as a hematopoietic euchromatin gatekeeper.
Assuntos
Agamaglobulinemia/genética , Cromatina/genética , Proteínas Proto-Oncogênicas/genética , Transativadores/genética , Adolescente , Adulto , Linfócitos B/fisiologia , Diferenciação Celular/genética , Linhagem Celular , Criança , Pré-Escolar , Células Dendríticas/fisiologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento/genética , Células HEK293 , Hematopoese/genética , Células-Tronco Hematopoéticas/fisiologia , Humanos , Lactente , Linfopoese/genética , Masculino , Mutação/genética , Células Precursoras de Linfócitos B/fisiologia , Células-Tronco/fisiologia , Adulto JovemRESUMO
BACKGROUND AIMS: Mesenchymal stromal cells (MSCs) have been applied to patients in cell therapy for various diseases. Recently, we introduced a novel MSC separation filter device which could yield approximately 2.5-fold more MSCs from bone marrow in a closed system compared with the conventional open density gradient centrifugation method. MSCs isolated with these two methods were phenotypically similar and met the criteria defining human MSC proposed by the International Society for Cellular Therapy. However, these criteria do not reflect the functional capacity of MSCs. It has been shown that the donor, source, isolation method, culture condition and cryopreservation of MSCs have potential to alter their therapeutic efficacy. To determine the equivalency of MSCs isolated by these two methods, we compared their genomic profiles as an index of their biologic potential and evaluated their growth promoting potential as an index of function. METHODS: The gene expression profiles of human MSCs isolated from 5 healthy donors with two distinct methods were obtained from microarray analyses. The functional activity of freshly expanded/cryopreserved MSCs from these two isolation methods was evaluated using an in vitro chondrocyte proliferation assay. RESULTS: Freshly expanded MSCs isolated by these two methods were found to exhibit similar gene expression profiles and equivalent therapeutic effects, while freshly thawed, cryopreserved MSCs lacked all measureable therapeutic activity. CONCLUSIONS: The MSC separation device generates genomically and functionally equivalent MSCs compared with the conventionally isolated MSCs, although freshly thawed, cryopreserved MSCs, isolated by either method, are devoid of activity in our bioassay.