RESUMEN
Biallelic mutations of the DNA annealing helicase SMARCAL1 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a-like 1) cause Schimke immuno-osseous dysplasia (SIOD, MIM 242900), an incompletely penetrant autosomal recessive disorder. Using human, Drosophila and mouse models, we show that the proteins encoded by SMARCAL1 orthologs localize to transcriptionally active chromatin and modulate gene expression. We also show that, as found in SIOD patients, deficiency of the SMARCAL1 orthologs alone is insufficient to cause disease in fruit flies and mice, although such deficiency causes modest diffuse alterations in gene expression. Rather, disease manifests when SMARCAL1 deficiency interacts with genetic and environmental factors that further alter gene expression. We conclude that the SMARCAL1 annealing helicase buffers fluctuations in gene expression and that alterations in gene expression contribute to the penetrance of SIOD.
Asunto(s)
Alelos , Arteriosclerosis/genética , ADN Helicasas/genética , Expresión Génica , Síndromes de Inmunodeficiencia/genética , Mutación , Síndrome Nefrótico/genética , Osteocondrodisplasias/genética , Embolia Pulmonar/genética , Animales , Arteriosclerosis/metabolismo , Cromatina/metabolismo , ADN Helicasas/metabolismo , Modelos Animales de Enfermedad , Drosophila/enzimología , Embrión no Mamífero/metabolismo , Ambiente , Humanos , Síndromes de Inmunodeficiencia/metabolismo , Ratones , Síndrome Nefrótico/metabolismo , Osteocondrodisplasias/metabolismo , Penetrancia , Enfermedades de Inmunodeficiencia Primaria , Embolia Pulmonar/metabolismoRESUMEN
Chronic granulomatous disease (CGD) is a primary immunodeficiency of defective neutrophil oxidative burst activity due to mutations in the genes CYBA, NCF-1, NCF-2, and CYBB, which respectively encode the p22-phox, p47-phox, p67-phox, and gp91-phox subunits. CGD usually presents in early childhood with recurrent or severe infection with catalase-positive bacteria and fungi. We present an unusual case of CGD in which Burkholderia cepacia lymphadenitis developed in a previously healthy 10-year-old girl. Flow cytometric analysis of dihydrorhodamine (DHR)-labeled neutrophils performed by a CLIA-approved outside reference laboratory was reported as normal. However, we found that this patient's neutrophil oxidative burst activity in DHR assays was substantially reduced but not absent. A selective decrease in intracellular staining for p67-phox suggested the diagnosis of autosomal recessive CGD due to NCF-2 gene mutations, and a novel homozygous and hypomorphic NCF-2 gene mutation was found. The potential mechanisms for this delayed and mild presentation of CGD are discussed.
Asunto(s)
Enfermedad Granulomatosa Crónica/diagnóstico , Enfermedad Granulomatosa Crónica/genética , Mutación , NADPH Oxidasas/genética , Infecciones por Burkholderia/complicaciones , Burkholderia cepacia , Niño , Aberraciones Cromosómicas , Femenino , Genes Recesivos , Genotipo , Enfermedad Granulomatosa Crónica/complicaciones , Homocigoto , Humanos , Neutrófilos/metabolismo , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Estallido Respiratorio , Coloración y EtiquetadoRESUMEN
CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg) play an important role in the induction and maintenance of immune tolerance. Although adoptive transfer of bulk populations of Treg can prevent or treat T cell-mediated inflammatory diseases and transplant allograft rejection in animal models, optimal Treg immunotherapy in humans would ideally use antigen-specific rather than polyclonal Treg for greater specificity of regulation and avoidance of general suppression. However, no robust approaches have been reported for the generation of human antigen-specific Treg at a practical scale for clinical use. Here, we report a simple and cost-effective novel method to rapidly induce and expand large numbers of functional human alloantigen-specific Treg from antigenically naive precursors in vitro using allogeneic nontransformed B cells as stimulators. By this approach naive CD4(+)CD25(-) T cells could be expanded 8-fold into alloantigen-specific Treg after 3 weeks of culture without any exogenous cytokines. The induced alloantigen-specific Treg were CD45RO(+)CCR7(-) memory cells, and had a CD4(high), CD25(+), Foxp3(+), and CD62L (L-selectin)(+) phenotype. Although these CD4(high)CD25(+)Foxp3(+) alloantigen-specific Treg had no cytotoxic capacity, their suppressive function was cell-cell contact dependent and partially relied on cytotoxic T lymphocyte antigen-4 expression. This approach may accelerate the clinical application of Treg-based immunotherapy in transplantation and autoimmune diseases.
Asunto(s)
Linfocitos B/inmunología , Isoantígenos/inmunología , Especificidad del Receptor de Antígeno de Linfocitos T , Linfocitos T Reguladores/inmunología , Presentación de Antígeno , Linfocitos B/citología , Antígenos CD40 , Comunicación Celular/inmunología , Técnicas de Cultivo de Célula/economía , Técnicas de Cultivo de Célula/métodos , Técnicas de Cocultivo , Humanos , Inmunofenotipificación , Métodos , Linfocitos T Reguladores/citologíaRESUMEN
BACKGROUND: Asymptomatic cytomegalovirus (CMV) replication is frequent after cardiac transplantation in recipients with pretransplantation CMV infection. How subclinical viral replication influences cardiac allograft disease remains poorly understood, as does the importance of T-cell immunity in controlling such replication. METHODS AND RESULTS: Thirty-nine cardiac recipients who were pretransplantation CMV antibody positive were longitudinally studied for circulating CMV-specific CD4 and CD8 T-cell responses, CMV viral load in blood neutrophils, and allograft rejection during the first posttransplantation year. Nineteen of these recipients were also analyzed for changes of coronary artery intimal, lumen, and whole-vessel area. All recipients received early prophylactic therapy with ganciclovir. No recipients developed overt CMV disease. Those with detectable levels of CMV-specific CD4 T cells in the first month after transplantation were significantly protected from high mean and peak posttransplantation viral load (P<0.05), acute rejection (P<0.005), and loss of allograft coronary artery lumen (P<0.05) and of whole-vessel area (P<0.05) compared with those who lacked this immune response. The losses of lumen and vessel area were both significantly correlated with the time after transplantation at which a CD4 T-cell response was first detected (P<0.05) and with the cumulative graft rejection score (P<0.05). CONCLUSIONS: The early control of subclinical CMV replication after transplantation by T-cell immunity may limit cardiac allograft rejection and vascular disease. Interventions to increase T-cell immunity might be clinically useful in limiting these adverse viral effects.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Enfermedad de la Arteria Coronaria/inmunología , Enfermedad de la Arteria Coronaria/prevención & control , Infecciones por Citomegalovirus/inmunología , Trasplante de Corazón/inmunología , Adulto , Antivirales/uso terapéutico , Linfocitos T CD4-Positivos/patología , Linfocitos T CD8-positivos/patología , Enfermedad de la Arteria Coronaria/etiología , Enfermedad de la Arteria Coronaria/patología , Vasos Coronarios/inmunología , Vasos Coronarios/patología , Citomegalovirus/inmunología , Citomegalovirus/patogenicidad , Infecciones por Citomegalovirus/tratamiento farmacológico , Infecciones por Citomegalovirus/patología , Femenino , Ganciclovir/uso terapéutico , Rechazo de Injerto/inmunología , Rechazo de Injerto/patología , Rechazo de Injerto/prevención & control , Trasplante de Corazón/efectos adversos , Trasplante de Corazón/patología , Humanos , Inmunidad Celular , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Túnica Íntima/inmunología , Túnica Íntima/patología , Carga Viral , Replicación Viral/inmunologíaRESUMEN
We show that STAT5b is important for the in vivo accumulation of CD4+ CD25(high) T cells with regulatory cell function. A patient homozygous for a missense A630P STAT5b mutation displayed immune dysregulation and decreased numbers of CD4+ CD25(high) T cells. STAT5b(A630P/A630P) CD4+ CD25(high) T cells had low expression of forkhead box P3 and an impaired ability to suppress the proliferation of or to kill CD4+ CD25- T cells. Expression of CD25, a component of the high-affinity IL-2R, was also reduced in response to IL-2 or after in vitro propagation. The impact of the STAT5b mutation was selective in that IL-2-mediated up-regulation of the common gamma-chain cytokine receptor and perforin, and activation-induced expressions of CD154 and IFN-gamma were normal. These results indicate that STAT5b propagates an important IL-2-mediated signal for the in vivo accumulation of functional regulatory T cells.