RESUMEN
Introduction: IL-2Rα knock out (KO) mice have been instrumental to discovering the immunoregulatory properties of IL-2Rα. While initially thought of only as a stimulatory cytokine, IL-2 and IL-2Rα KO mice revealed that this cytokine-receptor system controls immune responses through restimulation-induced cell death and by promoting the survival of T regulatory cells. Although described mostly in the context of lymphocytes, recent studies by our laboratory showed that IL-2R is expressed in smooth muscle cells. Given this finding, we sought to use IL-2Rα KO to determine the function of this receptor in vascular smooth muscle cells. Surprisingly, we found that IL-2Rα KO vascular smooth muscle cells had detectable IL-2Rα. Methods: We used multiple gene and protein-based methods to determine why IL-2Rα KO vascular smooth muscle cells exhibited IL-2Rα protein. These methods included: genomic sequencing, assessing cells and tissues for evidence of maternal microchimerism, and determining the half-life of IL-2Rα protein. Results: Our studies demonstrated the following: (1) in addition to the cell surface, IL-2Rα is localized to the nucleus; (2) the genetic deletion of IL-2Rα is intact in IL-2Rα KO mice; (3) both IL-2Rα KO and WT tissues show evidence of maternal microchimerism, the likely source of IL-2Rα (4) IL-2Rα is transmitted between cells; (5) IL-2Rα has a long half-life; and (6) nuclear IL-2Rα contributes to the regulation of cell proliferation and size. Conclusion: Our findings suggest that the phenotype of complete IL-2Rα loss is more severe than demonstrated by IL-2Rα KO mice, and that IL-2Rα plays a here-to-fore unrecognized role in regulating cell proliferation in non-lymphoid cells.
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Núcleo Celular , Subunidad alfa del Receptor de Interleucina-2 , Ratones Noqueados , Animales , Femenino , Ratones , Núcleo Celular/metabolismo , Quimerismo , Subunidad alfa del Receptor de Interleucina-2/metabolismo , Subunidad alfa del Receptor de Interleucina-2/genética , Linfocitos/inmunología , Linfocitos/metabolismo , Ratones Endogámicos C57BL , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/citología , Músculo Liso Vascular/inmunología , Miocitos del Músculo Liso/metabolismoRESUMEN
Although FOXP3+ regulatory T cells (Treg) depend on IL-2 produced by other cells for their survival and function, the levels of IL-2 in inflamed tissue are low, making it unclear how Treg access this critical resource. Here, we show that Treg use heparanase (HPSE) to access IL-2 sequestered by heparan sulfate (HS) within the extracellular matrix (ECM) of inflamed central nervous system tissue. HPSE expression distinguishes human and murine Treg from conventional T cells and is regulated by the availability of IL-2. HPSE-/- Treg have impaired stability and function in vivo, including in the experimental autoimmune encephalomyelitis (EAE) mouse model of multiple sclerosis. Conversely, endowing monoclonal antibody-directed chimeric antigen receptor (mAbCAR) Treg with HPSE enhances their ability to access HS-sequestered IL-2 and their ability to suppress neuroinflammation in vivo. Together, these data identify a role for HPSE and the ECM in immune tolerance, providing new avenues for improving Treg-based therapy of autoimmunity.
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Encefalomielitis Autoinmune Experimental , Linfocitos T Reguladores , Ratones , Animales , Humanos , Interleucina-2/metabolismo , Glucuronidasa/genética , Glucuronidasa/metabolismo , Matriz Extracelular/metabolismo , Heparitina Sulfato/metabolismoRESUMEN
IL-2Rα KO mice have been instrumental to discovering the immunoregulatory properties of IL-2Rα. While initially thought of only as a stimulatory cytokine, IL-2 and IL-2Rα knock out (KO) mice revealed that this cytokine-receptor system controls immune responses through restimulation-induced cell death and by promoting the survival of T regulatory cells. Although described mostly in the context of lymphocytes, recent studies by our laboratory showed that IL-2R is expressed in smooth muscle cells. Given this finding, we sought to use IL-2Rα knock mice to determine the function of this receptor in vascular smooth muscle cells. Surprisingly, we found that IL-2Rα knock out vascular smooth muscle cells had detectable IL-2Rα. Further studies suggested that the source of IL-2Rα protein was likely maternal heterozygous cells present in KO offspring due to maternal microchimerism. Because the KO was generated by using a neomycin resistance gene insert, we treated cells with G418 and were able to eliminate the majority of IL-2Rα expressing cells. This elimination revealed that IL-2Rα KO vascular smooth muscle cells exhibited increased proliferation, decreased size, and hypodiploid DNA content when compared to wildtype cells. Our findings suggest that the phenotype of complete IL-2Rα loss is more severe than demonstrated by IL-2Rα KO mice, and that IL-2Rα plays a here-to-fore unrecognized role in regulating cell proliferation in non-lymphoid cells.
RESUMEN
FOXP3+ regulatory T cells (Treg) depend on exogenous IL-2 for their survival and function, but circulating levels of IL-2 are low, making it unclear how Treg access this critical resource in vivo. Here, we show that Treg use heparanase (HPSE) to access IL-2 sequestered by heparan sulfate (HS) within the extracellular matrix (ECM) of inflamed central nervous system tissue. HPSE expression distinguishes human and murine Treg from conventional T cells and is regulated by the availability of IL-2. HPSE-/- Treg have impaired stability and function in vivo, including the experimental autoimmune encephalomyelitis (EAE) mouse model of multiple sclerosis. Conversely, endowing Treg with HPSE enhances their ability to access HS-sequestered IL-2 and their tolerogenic function in vivo. Together, these data identify novel roles for HPSE and the ECM in immune tolerance, providing new avenues for improving Treg-based therapy of autoimmunity.
RESUMEN
The ability of a cell to proliferate is integral to the normal function of most cells, and dysregulation of proliferation is at the heart of many disease processes. For these reasons, measuring proliferation is a common tool used to assess cell function. Cell proliferation can be measured simply by counting; however, this is an indirect means of measuring proliferation. One common means of directly detecting cells preparing to divide is by incorporation of labeled nucleoside analogs. These include the radioactive nucleoside analog 3H-thymidine plus non-radioactive nucleoside analogs such as 5-bromo-2' deoxyuridine (BrdU) and 5-ethynyl-2'-deoxyuridine (EdU). Incorporation of EdU is detected by click chemistry, which has several advantages when compared to BrdU. In this report, we provide a protocol for measuring proliferation by the incorporation of EdU. This protocol includes options for various readouts, along with the advantages and disadvantages of each. We also discuss places where the protocol can be optimized or altered to meet the specific needs of the experiment planned. Finally, we touch on the ways that this basic protocol can be modified for measuring other cell metabolites.
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Proliferación Celular , Músculo Liso Vascular/citología , Miocitos del Músculo Liso/citología , Coloración y Etiquetado/métodos , Células Cultivadas , Química Clic , ADN/química , Desoxiuridina/análogos & derivados , Desoxiuridina/química , Humanos , Arteria IlíacaRESUMEN
Many nonlymphoid cell types express at least two, if not all three, subunits of the IL-2R; although, compared with lymphocytes, relatively little is known about how IL-2 affects the function of nonlymphoid cells. The limited information available suggests that IL-2 has a substantial impact on cells such as gastrointestinal epithelial cells, endothelial cells, and fibroblasts. In a previous report from our laboratory, we noted that IL-2 and IL-2Rß-deficient mice lose smooth muscle cells over time, eventually resulting in aneurysmal aortas and ectatic esophagi. This finding, combined with our work showing that IL-2 surrounds vascular smooth muscle cells by association with perlecan, led us to ask whether vascular smooth muscle cells express an IL-2R. Toward this end, we reported the expression of IL-2Rß on human and murine vascular smooth muscle cells. We now report that vascular smooth muscle cells express all three subunits of the IL-2R, and that expression of IL-2Rα varies with vascular smooth muscle cell phenotype. Furthermore, we show that, through a functional IL-2R, IL-2 initiates signaling pathways and impacts vascular smooth muscle cell function. Finally, we demonstrate that IL-2 expression increases upon initiation of conditions that promote intimal hyperplasia, suggesting a mechanism by which the IL-2/IL-2R system may impact this widespread vascular pathology.
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Subunidad alfa del Receptor de Interleucina-2/genética , Interleucina-2/metabolismo , Miocitos del Músculo Liso/metabolismo , Animales , Aorta/citología , Arterias Carótidas/metabolismo , Arterias Carótidas/trasplante , Movimiento Celular , Proliferación Celular , Células Cultivadas , Humanos , Hiperplasia/metabolismo , Interleucina-2/farmacología , Subunidad alfa del Receptor de Interleucina-2/metabolismo , Células Jurkat , Ratones , Músculo Liso Vascular/citología , Conejos , Transducción de SeñalRESUMEN
The uptake of cholesterol carried by low-density lipoprotein (LDL) is tightly controlled in the body. Macrophages are not well suited to counteract the cellular consequences of excess cholesterol leading to their transformation into "foam cells," an early step in vascular plaque formation. We have uncovered and characterized a novel mechanism involving phospholipase D (PLD) in foam cell formation. Utilizing bone marrow-derived macrophages from genetically PLD deficient mice, we demonstrate that PLD2 (but not PLD1)-null macrophages cannot fully phagocytose aggregated oxidized LDL (Agg-Ox-LDL), which was phenocopied with a PLD2-selective inhibitor. We also report a role for PLD2 in coupling Agg-oxLDL phagocytosis with WASP, Grb2, and Actin. Further, the clearance of LDL particles is mediated by both CD36 and PLD2, via mutual dependence on each other. In the absence of PLD2, CD36 does not engage in Agg-Ox-LDL removal and when CD36 is blocked, PLD2 cannot form protein-protein heterocomplexes with WASP or Actin. These results translated into humans using a GEO database of microarray expression data from atheroma plaques versus normal adjacent carotid tissue and observed higher values for NFkB, PLD2 (but not PLD1), WASP, and Grb2 in the atheroma plaques. Human atherectomy specimens confirmed high presence of PLD2 (mRNA and protein) as well as phospho-WASP in diseased arteries. Thus, PLD2 interacts in macrophages with Actin, Grb2, and WASP during phagocytosis of Agg-Ox-LDL in the presence of CD36 during their transformation into "foam cells." Thus, this study provides new molecular targets to counteract vascular plaque formation and atherogenesis.
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Antígenos CD36/metabolismo , Células Espumosas/patología , Lipoproteínas LDL/metabolismo , Fagocitosis , Fosfolipasa D/fisiología , Placa Aterosclerótica/patología , Animales , Antígenos CD36/genética , Células Cultivadas , Colesterol/metabolismo , Femenino , Células Espumosas/metabolismo , Proteína Adaptadora GRB2/genética , Proteína Adaptadora GRB2/metabolismo , Humanos , Macrófagos/metabolismo , Macrófagos/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Placa Aterosclerótica/genética , Placa Aterosclerótica/metabolismo , Proteína del Síndrome de Wiskott-Aldrich/genética , Proteína del Síndrome de Wiskott-Aldrich/metabolismoRESUMEN
INTRODUCTION: The two most significant impediments to renal allograft survival are rejection and the direct nephrotoxicity of the immunosuppressant drugs required to prevent it. Calcineurin inhibitors (CNI), a mainstay of most immunosuppression regimens, are particularly nephrotoxic. Until less toxic antirejection agents become available, the only option is to optimize our use of those at hand. AIM: To determine whether intensive rabbit anti-thymocyte globulin (rATG) induction followed by CNI withdrawal would individually or combined improve graft function and reduce graft chronic histopathology-surrogates for graft and, therefore, patient survival. As previously reported, a single large rATG dose over 24 hours was well-tolerated and associated with better renal function, fewer infections, and improved patient survival. Here we report testing whether complete CNI discontinuation would improve renal function and decrease graft pathology. METHODS: Between April 20, 2004 and 4-14-2009 we conducted a prospective, randomized, non-blinded renal transplantation trial of two rATG dosing protocols (single dose, 6 mg/kg vs. divided doses, 1.5 mg/kg every other day x 4; target enrollment = 180). Subsequent maintenance immunosuppression consisted of tacrolimus, a CNI, and sirolimus, a mammalian target of rapamycin inhibitor. We report here the outcome of converting patients after six months either to minimized tacrolimus/sirolimus or mycophenolate mofetil/sirolimus. Primary endpoints were graft function and chronic histopathology from protocol kidney biopsies at 12 and 24 months. RESULTS: CNI withdrawal (on-treatment analysis) associated with better graft function (p <0.001) and lower chronic histopathology composite scores in protocol biopsies at 12 (p = 0.003) and 24 (p = 0.013) months, without affecting patient (p = 0.81) or graft (p = 0.93) survival, or rejection rate (p = 0.17). CONCLUSION: CNI (tacrolimus) withdrawal at six months may provide a strategy for decreased nephrotoxicity and improved long-term function in steroid-free low immunological risk renal transplant patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT00556933.
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Inhibidores de la Calcineurina/administración & dosificación , Terapia de Inmunosupresión/métodos , Inmunosupresores/administración & dosificación , Trasplante de Riñón , Riñón/efectos de los fármacos , Esteroides/administración & dosificación , Adolescente , Adulto , Anciano , Animales , Suero Antilinfocítico/química , Biopsia , Esquema de Medicación , Femenino , Rechazo de Injerto/prevención & control , Humanos , Masculino , Persona de Mediana Edad , Ácido Micofenólico/administración & dosificación , Ácido Micofenólico/análogos & derivados , Estudios Prospectivos , Conejos , Sirolimus/administración & dosificación , Tacrolimus/administración & dosificación , Factores de Tiempo , Adulto JovenRESUMEN
Tissue and organ transplants between genetically distinct individuals are always or nearly always rejected. The universality and speed of transplant rejection distinguishes this immune response from all others. Although this distinction is incompletely understood, some efforts to shed light on transplant rejection have revealed broader insights, including a relationship between activation of complement in grafted tissues, the metabolism of heparan sulfate proteoglycan and the nature of immune and inflammatory responses that ensue. Complement activation on cell surfaces, especially on endothelial cell surfaces, causes the shedding heparan sulfate, an acidic saccharide, from the cell surface and neighboring extracellular matrix. Solubilized in this way, heparan sulfate can activate leukocytes via toll like receptor-4, triggering inflammatory responses and activating dendritic cells, which migrate to regional lymphoid organs where they spark and to some extent govern cellular immune responses. In this way local ischemia, tissue injury and infection, exert systemic impact on immunity. Whether or in what circumstances this series of events explains the distinct characteristics of the immune response to transplants is still unclear but the events offer insight into the inception of immunity under the sub-optimal conditions accompanying infection and mechanisms by which infection and tissue injury engender systemic inflammation.
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Rechazo de Injerto/metabolismo , Proteoglicanos de Heparán Sulfato/metabolismo , Heparitina Sulfato/metabolismo , Síndrome de Respuesta Inflamatoria Sistémica/metabolismo , Trasplante de Tejidos , Activación de Complemento/efectos de los fármacos , Proteínas del Sistema Complemento/efectos de los fármacos , Proteínas del Sistema Complemento/genética , Células Dendríticas/efectos de los fármacos , Células Dendríticas/inmunología , Células Dendríticas/patología , Células Endoteliales/efectos de los fármacos , Células Endoteliales/inmunología , Células Endoteliales/patología , Matriz Extracelular/efectos de los fármacos , Matriz Extracelular/metabolismo , Regulación de la Expresión Génica , Rechazo de Injerto/genética , Rechazo de Injerto/inmunología , Rechazo de Injerto/patología , Proteoglicanos de Heparán Sulfato/inmunología , Heparitina Sulfato/inmunología , Heparitina Sulfato/farmacología , Humanos , Leucocitos/efectos de los fármacos , Leucocitos/inmunología , Leucocitos/patología , Transducción de Señal , Síndrome de Respuesta Inflamatoria Sistémica/genética , Síndrome de Respuesta Inflamatoria Sistémica/inmunología , Síndrome de Respuesta Inflamatoria Sistémica/patología , Receptor Toll-Like 4/genética , Receptor Toll-Like 4/inmunologíaRESUMEN
BACKGROUND: We conducted a randomized and unblinded 2 × 2 sequential-factorial trial, composed of an induction arm (part 1) comparing single-dose (SD) versus divided-dose rabbit antithymocyte globulin (rATG), and a maintenance arm (part 2) comparing tacrolimus minimization versus withdrawal. We report the long-term safety and efficacy of SD-rATG induction in the context of early steroid withdrawal and tacrolimus minimization or withdrawal. METHODS: Patients (n=180) received 6 mg/kg rATG, SD or four alternate-day doses (1.5 mg/kg/dose), with early steroid withdrawal and tacrolimus or sirolimus maintenance. After 6 months targeted maintenance levels were tacrolimus, 2 to 4 ng/mL and sirolimus, 4 to 6 ng/mL or, if calcineurin inhibitor-withdrawn, sirolimus 8 to 12 ng/mL with mycophenolate mofetil 2 g two times per day. Primary endpoints were renal function (abbreviated modification of diet in renal disease) and chronic graft histopathology (Banff). Secondary endpoints included patient survival, graft survival, biopsy-proven rejection, and infectious or noninfectious complications. RESULTS: Follow-up averaged longer than 4 years. Tacrolimus or sirolimus and mycophenolate mofetil exposure was identical between groups. The SD-rATG associated with improved renal function (2-36 months; P<0.001) in deceased donor recipients. The SD-rATG associated with quicker lymphocyte, CD4 T cell, and CD4-CD8 recovery and fewer infections. Cox multivariate hazard modeling showed divided-dose-rATG (P=0.019), deceased donor (P=0.003), serious infection (P=0.0.018), and lower lymphocyte count (P=0.001) associated with increased mortality. Patients with all four covariates showed a 27-fold increased likelihood of death (P=0.00002). Chronic graft histopathology, rejection rates, and death-censored graft survival were not significantly different between groups. CONCLUSION: The SD-rATG induction improves the 3-year renal function in recipients of deceased donor kidneys. This benefit, along with possibly improved patient survival and fewer infections suggest that how rATG is administered may impact its efficacy and safety.
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Suero Antilinfocítico/administración & dosificación , Rechazo de Injerto/prevención & control , Supervivencia de Injerto/efectos de los fármacos , Inmunosupresores/administración & dosificación , Trasplante de Riñón/efectos adversos , Adulto , Animales , Suero Antilinfocítico/efectos adversos , Esquema de Medicación , Quimioterapia Combinada , Femenino , Rechazo de Injerto/diagnóstico , Rechazo de Injerto/inmunología , Rechazo de Injerto/mortalidad , Humanos , Inmunosupresores/efectos adversos , Estimación de Kaplan-Meier , Trasplante de Riñón/mortalidad , Masculino , Persona de Mediana Edad , Análisis Multivariante , Ácido Micofenólico/administración & dosificación , Ácido Micofenólico/análogos & derivados , Modelos de Riesgos Proporcionales , Conejos , Factores de Riesgo , Sirolimus/administración & dosificación , Esteroides/administración & dosificación , Tacrolimus/administración & dosificación , Factores de Tiempo , Resultado del TratamientoRESUMEN
Interleukin-2 (IL-2) is a multi-faceted cytokine, known for promoting proliferation, survival, and cell death depending on the cell type and state. For example, IL-2 facilitates cell death only in activated T cells when antigen and IL-2 are abundant. The availability of IL-2 clearly impacts this process. Our laboratory recently demonstrated that IL-2 is retained in blood vessels by heparan sulfate, and that biologically active IL-2 is released from vessel tissue by heparanase. We now demonstrate that heparanase digestion also releases a dimeric form of IL-2 that is highly cytotoxic to cells expressing the IL-2 receptor. These cells include "traditional" IL-2 receptor-bearing cells such as lymphocytes, as well as those less well known for IL-2 receptor expression, such as epithelial and smooth muscle cells. The morphologic changes and rapid cell death induced by dimeric IL-2 imply that cell death is mediated by disruption of membrane permeability and subsequent necrosis. These findings suggest that IL-2 has a direct and unexpectedly broad influence on cellular homeostatic mechanisms in both immune and non-immune systems.
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Muerte Celular/efectos de los fármacos , Permeabilidad de la Membrana Celular/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Interleucina-2/química , Interleucina-2/toxicidad , Linfocitos/efectos de los fármacos , Miocitos del Músculo Liso/efectos de los fármacos , Animales , Western Blotting , Dimerización , Células Epiteliales/metabolismo , Linfocitos/metabolismo , Ratones , Ratones Endogámicos BALB C , Miocitos del Músculo Liso/metabolismo , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
BACKGROUND: Rabbit anti-thymocyte globulin (rATG) induction reduces reperfusion injury and improves renal function in kidney recipients by means of properties unrelated to T-cell lysis. Here, we analyze intensive rATG induction (single dose, rATG(S) , vs. divided dose, rATG(D) ) for improved renal function and protection against hyperglycemia. METHODS: Patients without diabetes (n = 98 of 180) in a prospective randomized trial of intensive rATG induction were followed for six months for the major secondary composite end point of impaired glucose regulation (hyperglycemia and new-onset diabetes after transplantation, NODAT). Prospectively collected data included fasting blood glucose and HbA(1c). Serum Mg(++) was routinely collected and retrospectively analyzed. RESULTS: Induction with rATG(S) produced less impaired glucose regulation (p = 0.05), delayed NODAT development (p = 0.02), less hyperglycemia (p = 0.02), better renal function (p = 0.04), and less hypomagnesemia (p = 0.02), a factor associated with a lower incidence of NODAT. Generalized linear modeling confirmed that rATG(S) protects against a synergistic interaction between tacrolimus and sirolimus that otherwise increased hypomagnesemia (p = 0.008) and hyperglycemia (p = 0.03). CONCLUSIONS: rATG(S) initiated before renal reperfusion improved early renal function and reduced impaired glucose regulation, an injury by diabetogenic maintenance agents (tacrolimus and sirolimus).
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Suero Antilinfocítico/administración & dosificación , Glucemia/metabolismo , Diabetes Mellitus/prevención & control , Rechazo de Injerto/prevención & control , Hiperglucemia/prevención & control , Trasplante de Riñón , Defectos Congénitos del Transporte Tubular Renal/prevención & control , Adulto , Anciano , Animales , Diabetes Mellitus/etiología , Femenino , Estudios de Seguimiento , Humanos , Hiperglucemia/etiología , Inmunosupresores/uso terapéutico , Pruebas de Función Renal , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos , Conejos , Defectos Congénitos del Transporte Tubular Renal/etiología , Tasa de Supervivencia , Adulto JovenRESUMEN
Interleukin-2 (IL-2) is a multifaceted cytokine with immunostimulatory and immunosuppressive properties. Our laboratory recently demonstrated that the availability of IL-2 is regulated, in part, by association with perlecan, a heparan sulfate proteoglycan. Given the abundance of perlecan in blood vessels, we asked whether IL-2 is present in vessel walls. Our results indicate that IL-2 is associated with endothelial and smooth muscle cells within the human arterial wall. This IL-2 is released by heparanase, and promotes the proliferation of an IL-2-dependent cell line. Given the presence of IL-2 in human arteries, we asked whether the large vessels of IL-2-deficient mice were normal. The aortas of IL-2-deficient mice exhibited a loss of smooth muscle cells, suggesting that IL-2 may contribute to their survival. In their entirety, these results suggest a here-to-fore unrecognized role of IL-2 in vascular biology, and have significant implications for both the immune and cardiovascular systems.
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Endotelio Vascular/metabolismo , Glucuronidasa/metabolismo , Interleucina-2/metabolismo , Músculo Liso Vascular/metabolismo , Animales , Aneurisma de la Aorta/metabolismo , Arterias/citología , Arterias/metabolismo , Células Cultivadas , Células Endoteliales/metabolismo , Proteínas de la Matriz Extracelular/metabolismo , Proteoglicanos de Heparán Sulfato/metabolismo , Humanos , Ratones , Ratones Noqueados , Receptores de Interleucina-2/metabolismoAsunto(s)
Diabetes Mellitus/tratamiento farmacológico , Inhibidores de la Dipeptidil-Peptidasa IV/uso terapéutico , Trasplante de Riñón/efectos adversos , Pirazinas/uso terapéutico , Triazoles/uso terapéutico , Femenino , Tasa de Filtración Glomerular , Hemoglobina Glucada/análisis , Humanos , Masculino , Persona de Mediana Edad , Pirazinas/efectos adversos , Fosfato de Sitagliptina , Triazoles/efectos adversosAsunto(s)
Trasplante de Riñón/efectos adversos , Mielitis Transversa/etiología , Trasplante de Páncreas/efectos adversos , Parálisis/etiología , Complicaciones Posoperatorias/etiología , Adulto , Diabetes Mellitus Tipo 1/complicaciones , Humanos , Inmunosupresores/efectos adversos , Inmunosupresores/uso terapéutico , Inflamación , Imagen por Resonancia Magnética/métodos , Masculino , Páncreas/patología , Insuficiencia Renal/terapia , Linfocitos T/inmunologíaRESUMEN
BACKGROUND: The optimal dosing protocol for rabbit anti-thymocyte globulin (rATG) induction in renal transplantation has not been determined, but evidence exists that rATG infusion before renal allograft reperfusion improves early graft function. Infusing a large rATG dose over a short interval has not previously been evaluated for its effect on renal function and allograft nephropathy in a prospective, randomized comparison against conventional rATG induction. METHODS: Between April 20, 2004 and December 26, 2007 we enrolled renal transplant patients into a prospective, randomized, nonblinded trial of two rATG dosing protocols (single dose, 6 mg/kg vs. divided doses, 1.5 mg/kg every other day x 4; target enrollment=160) followed after 6 months by calcineurin-inhibitor withdrawal. Primary endpoints are renal function by calculated glomerular filtration rate (GFR) and chronic allograft nephropathy at protocol biopsy. We now present the early GFR data of all 160 patients and safety and efficacy data of the first 142 patients with 6 months follow up and before calcineurin inhibitor withdrawal (average follow up=23.3+/-11.6 months). RESULTS: There were no differences between groups in rATG-related adverse events, patient and graft survival, acute rejection, or chronic allograft nephropathy rate at 6 months. Calculated DeltaGFR (POD 1-4) was significantly better in the single-dose group (P=0.02), with a trend toward improved renal function from months 2 to 6 in recipients of deceased donor kidneys (P=0.08). CONCLUSIONS: This study demonstrates that administering 6 mg/kg of rATG over 24 hr is safe and is associated with improved early renal function compared with administering rATG in alternate-day doses.
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Suero Antilinfocítico/uso terapéutico , Trasplante de Riñón/inmunología , Adulto , Animales , Suero Antilinfocítico/administración & dosificación , Esquema de Medicación , Monitoreo de Drogas/métodos , Quimioterapia Combinada , Femenino , Tasa de Filtración Glomerular , Supervivencia de Injerto/efectos de los fármacos , Humanos , Trasplante de Riñón/efectos adversos , Trasplante de Riñón/mortalidad , Masculino , Persona de Mediana Edad , Selección de Paciente , Conejos , Sirolimus/uso terapéutico , Análisis de Supervivencia , Tacrolimus/uso terapéutico , Trasplante HomólogoRESUMEN
Although interleukin-2 (IL-2) is typically considered a soluble cytokine, our laboratory has shown that the availability of IL-2 in lymphoid tissues is regulated, in part, by an association with heparan sulfate glycosaminoglycan. Heparan sulfate is usually found in proteoglycan form, in which the heparan sulfate chains are covalently linked to a specific core protein. We now show that perlecan is one of the major IL-2-binding heparan sulfate proteoglycans in murine spleen. IL-2 binds perlecan via heparan sulfate chains, as enzymatic removal of heparan sulfate from splenic perlecan abolishes its ability to bind IL-2. Furthermore, we demonstrate that perlecan-bound IL-2 supports the proliferation of an IL-2-dependent cell line. Identification of perlecan as a major heparan sulfate proteoglycan that binds IL-2 has implications for both the localization and regulation of IL-2 in vivo.
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Proteoglicanos de Heparán Sulfato/inmunología , Interleucina-2/metabolismo , Bazo/inmunología , Animales , Proliferación Celular , Proteoglicanos de Heparán Sulfato/aislamiento & purificación , Proteoglicanos de Heparán Sulfato/metabolismo , Humanos , Interleucina-2/inmunología , Ratones , Bazo/citología , Bazo/metabolismoRESUMEN
The production of auto-antibodies is one of the predominant characteristics of autoimmune disorders. Because IL-2 deficient mice develop autoimmunity, we asked how IL-2 deficiency might impair endogenous mechanisms of B cell tolerance. To this end, we mated BALB/c anti-dsDNA H chain knock-in mice, in which B cells producing anti-dsDNA antibodies are properly regulated, with IL-2 deficient mice and assessed the phenotype of their offspring. IL-2 deficient mice expressing the anti-dsDNA H chain knock-in allele developed anti-dsDNA antibodies of both IgM and IgG isotypes. Production of these antibodies occurred through the disruption of several mechanisms of endogenous tolerance, including deletion, maturational arrest, and follicular exclusion. In summary, our results suggest that IL-2 plays an important role in regulating B cell tolerance.
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Anticuerpos Antinucleares/biosíntesis , Autoinmunidad , Linfocitos B/inmunología , Tolerancia Inmunológica , Interleucina-2/deficiencia , Interleucina-2/inmunología , Bazo/inmunología , Animales , Anticuerpos Antinucleares/inmunología , Apoptosis , Linfocitos B/citología , Linfocitos B/metabolismo , Quimiocinas/aislamiento & purificación , Quimiocinas/metabolismo , Interleucina-2/genética , Interleucina-2/metabolismo , Ratones , Ratones Endogámicos BALB C , Bazo/citología , Bazo/metabolismoRESUMEN
The role of interleukin-2 (IL-2) in thymic development is uncertain. Not surprisingly, IL-2 knockout (KO) mice have been used to address this question. However, as we report here, such mice are chimeric, containing both IL-2 KO cells and IL-2-expressing cells transferred in utero from their heterozygous mothers. These cells produce IL-2 in amounts detectable by conventional means, and their presence in lymphoid tissues confounds efforts to define the true IL-2 KO phenotype. To minimize the amount of IL-2 available to the thymus, we subjected recombinase activating gene-1 KO mice to bone marrow transplantation using IL-2 KO donors, and then followed the reconstitution of the thymus. The thymuses of these mice became increasingly aberrant over time, including abnormalities in both stromal cells and thymocytes. These results demonstrate that IL-2 is critical to several aspects of thymic function, a finding previously obscured by the presence of IL-2 in IL-2 KO mice.
Asunto(s)
Quimerismo , Interleucina-2/fisiología , Timo/inmunología , Animales , Diferenciación Celular/inmunología , Supervivencia Celular/inmunología , Femenino , Proteínas de Homeodominio/genética , Inmunofenotipificación , Interleucina-2/genética , Proteína Tirosina Quinasa p56(lck) Específica de Linfocito/metabolismo , Intercambio Materno-Fetal/inmunología , Ratones , Ratones Noqueados , Ratones Transgénicos , Especificidad de Órganos , Fosforilación , Embarazo , Linfocitos T/inmunología , Timo/patologíaRESUMEN
Although West Nile fever is mild in the vast majority of infected persons, there is growing evidence that the disease may be more severe in the immunocompromised population. We describe 3 recipients of kidney or pancreas transplants who developed West Nile fever, 2 of whom had meningoencephalitis. As is the norm when treating serious infections in transplant recipients, a reduction of immunosuppression was pursued for these patients. Despite the severe nature of the disease in 2 patients, all recovered from the disease. The time course of neurologic recovery in the 2 patients with meningoencephalitis is highlighted. We also review the literature on West Nile fever in organ transplant recipients. In areas where West Nile virus is endemic, one must have a high index of suspicion for the illness when dealing with fever in transplant recipients.