RESUMEN
AIM: Protease inhibitors with pegylated interferon (PEG IFN)/ribavirin improve a sustained virological response (SVR) rate to approximately 90% in chronic hepatitis C genotype 1b patients with IL28B rs8099917 genotype TT, but yield only approximately 50% in those with the unfavorable non-TT. Among such treatment-refractory patients, serum vitamin D levels could influence the SVR rate. This randomized controlled trial was conducted to assess the effect of native vitamin D supplementation in simeprevir with PEG IFN/ribavirin for 1b patients with non-TT. METHODS: Patients were randomly assigned to receive simeprevir (100 mg/day) for 12 weeks plus PEG IFN/ribavirin for 24 weeks (control group, n = 58), or vitamin D (2000 IU/day) for 16 weeks including a lead-in phase plus PEG IFN/ribavirin for 24 weeks (vitamin D group, n = 57). The primary end-point was sustainably undetectable viremia 24 weeks after the end of treatment (SVR). RESULTS: SVR rates were 37.9% in the control group and 70.2% in the vitamin D group. In subgroup analysis, SVR rates of prior null responders were 11.8% and 54.5%, respectively. SVR rates for advanced fibrosis were 28.6% and 65.4%. SVR rates for patients with vitamin D3 deficiency at the baseline were 25.0% in the control group and 66.7% in the vitamin D group. Overall, the SVR rate was significantly higher in patients with high serum 25(OH)D3 levels at the beginning of combination therapy than in those with low serum 25(OH)D3 levels. CONCLUSION: Native vitamin D3 supplementation improved SVR rates in simeprevir with PEG IFN/ribavirin for chronic hepatitis C genotype 1b patients with refractory factors.
RESUMEN
BACKGROUND: Serum 25-hydroxyvitamin D3 levels are generally lower in chronic hepatitis C patients than in healthy individuals. The purpose of this study is to clarify the factors which affect serum 25-hydroxyvitamin D3 levels using data obtained from Japanese chronic hepatitis C patients. METHODS: The subjects were 619 chronic hepatitis C patients. Serum 25-hydroxyvitamin D3 levels were measured by using double-antibody radioimmunoassay between April 2009 and August 2014. Serum 25-hydroxyvitamin D3 levels of 20 ng/mL or less were classified as vitamin D deficiency, and those with serum 25-hydroxyvitamin D3 levels of 30 ng/mL or more as vitamin D sufficiency. The relationship between patient-related factors and serum 25-hydroxyvitamin D3 levels was analyzed. RESULTS: The cohort consisted of 305 females and 314 males, aged between 18 and 89 years (median, 63 years). The median serum 25-hydroxyvitamin D3 level was 21 ng/mL (range, 6-61 ng/mL). On the other hand, the median serum 25-hydroxyvitamin D3 level in the healthy subjects was 25 ng/mL (range, 7-52), being significantly higher than that those in 80 chronic hepatitis C patients matched for age, gender, and season (p = 1.16 × 10(-8)). In multivariate analysis, independent contributors to serum 25-hydroxyvitamin D3 deficiency were as follows: female gender (p = 2.03 × 10(-4), odds ratio = 2.290, 95 % confidence interval = 1.479-3.545), older age (p = 4.30 × 10(-4), odds ratio = 1.038, 95 % confidence interval = 1.017-1.060), cold season (p = 0.015, odds ratio = 1.586, 95 % confidence interval = 1.095-2.297), and low hemoglobin level (p = 0.037, odds ratio = 1.165, 95 % confidence interval = 1.009-1.345). By contrast, independent contributors to serum 25-hydroxyvitamin D3 sufficiency were male gender (p = 0.001, odds ratio = 3.400, 95 % confidence interval = 1.635-7.069), warm season (p = 0.014, odds ratio = 1.765, 95 % confidence interval = 1.117-2.789) and serum albumin (p = 0.016, OR = 2.247, 95 % CI = 1.163-4.342). CONCLUSIONS: Serum 25-hydroxyvitamin D3 levels in chronic hepatitis C Japanese patients were influenced by gender, age, hemoglobin level, albumin and the season of measurement.
Asunto(s)
Calcifediol/sangre , Hepatitis C Crónica/sangre , Deficiencia de Vitamina D/sangre , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Anemia/sangre , Anemia/epidemiología , Estudios de Casos y Controles , Femenino , Hemoglobinas/metabolismo , Hepatitis C Crónica/epidemiología , Humanos , Japón/epidemiología , Masculino , Persona de Mediana Edad , Análisis Multivariante , Oportunidad Relativa , Radioinmunoensayo , Factores de Riesgo , Estaciones del Año , Albúmina Sérica , Factores Sexuales , Deficiencia de Vitamina D/epidemiología , Adulto JovenRESUMEN
We report a case of fulminant hepatitis that was caused by XELOX therapy administered for metastatic rectal cancer. A 69- year-old man with metastatic rectal cancer received 4 courses XELOX therapy. He was subsequently admitted to our hospital with general fatigue. Shenzhen flapping and altered consciousness were noticed on the fifth day of hospitalization. A liver biopsy was subsequently performed. The patient was diagnosed with liver failure due to sinusoidal obstruction syndrome caused by oxaliplatin. This case provides valuable information as there are only a few reports of fulminant hepatitis caused by oxaliplatin.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Desoxicitidina/análogos & derivados , Fluorouracilo/análogos & derivados , Hepatitis/etiología , Neoplasias del Recto/tratamiento farmacológico , Anciano , Capecitabina , Desoxicitidina/efectos adversos , Fluorouracilo/efectos adversos , Hepatitis/patología , Hepatitis/terapia , Humanos , Masculino , Metástasis de la Neoplasia , Oxaloacetatos , Neoplasias del Recto/patologíaRESUMEN
OBJECTIVES: To compare the effectiveness and safety of low-dose sulfamethoxazole/trimethoprim (SMX/TMP) for Pneumocystis jirovecii pneumonia (PCP) prophylaxis in patients with systemic rheumatic disease (SRD) who were receiving glucocorticoids. METHODS: We retrospectively analyzed data obtained from Japanese patients with SRD who received glucocorticoids between January 2006 and April 2024. Patients were divided into two groups based on the initial dose of SMX/TMP: low-dose (one tablet twice weekly on non-consecutive days); conventional-dose (one tablet per day). The primary endpoint was the incidence of PCP after 1 year since the initiation of SMX/TMP. Secondary endpoints were discontinuation rates of SMX/TMP therapy and severe adverse drug reactions (ADRs) after 1 year since the initiation of SMX/TMP in both groups, before and after adjusting for patient characteristics. RESULTS: A total of 186 patients were included in this study: 60 in the low-dose group and 126 in the conventional-dose group. No patients developed PCP within one year after starting SMX/TMP; however, two patients in the low-dose group required escalation of the SMX/TMP dose to the conventional dose due to subclinical PCP. In the adjusted analysis, the low-dose group had a significantly lower discontinuation rate and a lower incidence rate of severe ADRs than the conventional-dose group. CONCLUSIONS: Lower-dose SMX/TMP therapy was as effective as conventional therapy for PCP prophylaxis and was associated with lower discontinuation rates in patients with SRD receiving glucocorticoids.
RESUMEN
We analyzed the clinical efficacy and safety of capecitabine plus oxaliplatin( XELOX) and bevacizumab( BV) as neoadjuvant chemotherapy, administered for the treatment of patients with resectable metastatic colorectal cancer between October 2009 and December 2012. Of the 15 patients who received chemotherapy, 9 received XELOX plus BV and 6 patients received XELOX alone. The median number of therapy courses was 4. The overall response rate was 73.3%. All patients underwent R0 resection. The median disease-free survival was 522 days. The median follow-up time was 607 days. No major Grade 3 or 4 adverse events occurred during chemotherapy and no perioperative complications were noted. Our findings suggest that XELOX (plus BV) as neoadjuvant therapy is useful for the prevention of early recurrence and is clinically efficacious and safe for the treatment of colorectal cancer with resectable metastases.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Colorrectales/tratamiento farmacológico , Terapia Neoadyuvante , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Capecitabina , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/cirugía , Desoxicitidina/administración & dosificación , Desoxicitidina/efectos adversos , Desoxicitidina/análogos & derivados , Femenino , Fluorouracilo/administración & dosificación , Fluorouracilo/efectos adversos , Fluorouracilo/análogos & derivados , Humanos , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Estadificación de Neoplasias , OxaloacetatosRESUMEN
The global outbreak of coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus type 2 has prompted the rapid spread and development of vaccines to prevent the spread of the disease. COVID-19 vaccine has demonstrated excellent efficacy in reducing morbidity and severity of the disease, and most adverse reactions are very minor. However, some patients have been reported to develop autoimmune diseases, such as rheumatoid arthritis, myocarditis, Guillain-Barre syndrome, and vasculitis, following COVID-19 vaccination. Herein, we present a case of polyarteritis nodosa with epididymitis, following COVID-19 mRNA vaccination. The patient's initial symptoms were fever and testicular pain, and magnetic resonance imaging showed epididymitis. He was diagnosed as having polyarteritis nodosa with epididymitis and was treated with high-dose prednisolone, with a good clinical outcome.
Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , Epididimitis , Poliarteritis Nudosa , Humanos , Masculino , COVID-19/diagnóstico , COVID-19/prevención & control , Vacunas contra la COVID-19/efectos adversos , Epididimitis/diagnóstico , Epididimitis/etiología , Poliarteritis Nudosa/diagnóstico , Poliarteritis Nudosa/etiología , VacunaciónRESUMEN
Eosinophilic granulomatosis with polyangiitis (EGPA) is a small- to medium-vessel necrotising vasculitis and eosinophilic inflammation. Mepolizumab, an anti-interleukin-5 (IL-5) monoclonal antibody has been approved in Japan since 2018 for refractory EGPA treatment. Benralizumab, an anti-IL-5 receptor monoclonal antibody, also has been reported to reduce the glucocorticoid dose in patients with refractory EGPA. On the other hand, several investigators have demonstrated new-onset EGPA under biologics, and it is unclear whether this treatment for severe allergic diseases can prevent the development of EGPA. Herein, we report a case of new-onset EGPA under benralizumab treatment. The patient had fever, weight loss, muscle pain, and paraesthesia, the serum eosinophil count was 0/µL, and the biopsy showed necrotizing vasculitis without eosinophilic infiltration. She was diagnosed as having EGPA and treated with high-dose glucocorticoid and intravenous cyclophosphamide, with a good response. Our case report indicates that anti-IL-5 agents may mask the development of EGPA and clinicians should be aware of the development of EGPA during anti-IL-5 agents.
Asunto(s)
Síndrome de Churg-Strauss , Eosinofilia , Granulomatosis con Poliangitis , Femenino , Humanos , Síndrome de Churg-Strauss/complicaciones , Síndrome de Churg-Strauss/diagnóstico , Síndrome de Churg-Strauss/tratamiento farmacológico , Glucocorticoides/uso terapéutico , Granulomatosis con Poliangitis/complicaciones , Granulomatosis con Poliangitis/diagnóstico , Granulomatosis con Poliangitis/tratamiento farmacológico , Eosinofilia/diagnóstico , Eosinofilia/tratamiento farmacológico , Eosinofilia/etiologíaRESUMEN
The coronavirus disease (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 has led to rapid progress in vaccine development to prevent the spread of the disease. Although COVID-19 vaccines have excellent effectiveness in reducing morbidity and disease severity with minor adverse reactions, some patients develop late hypersensitivity events as autoimmune reactions such as rheumatoid arthritis, lupus nephritis, and vasculitis following COVID-19 vaccination. Herein, we describe a case of pneumonitis following COVID-19 mRNA vaccination in a patient with rheumatoid arthritis, which resolved spontaneously.
RESUMEN
Coronavirus disease 2019 (COVID-19) has spread worldwide since 2019, and mRNA vaccines for the disease have been rapidly delivered to limit the severity of infection. However, while these vaccines are effective in reducing the morbidity and severity of the disease, some patients develop severe adverse drug reactions and new-onset autoimmune phenomena, such as myocarditis, thrombosis with thrombocytopenia, and vasculitis. In addition, some patients develop arthritis following vaccination, including rheumatoid arthritis (RA). We herein report a case of new-onset seropositive RA following COVID-19 mRNA vaccination. Although tests for rheumatoid factor and anti-cyclic citrullinated peptide antibody had been negative three years before vaccination, the patient developed seropositive RA following COVID-19 mRNA vaccination.
Asunto(s)
Artritis Reumatoide , Vacunas contra la COVID-19 , COVID-19 , Humanos , Artritis Reumatoide/complicaciones , Artritis Reumatoide/tratamiento farmacológico , COVID-19/prevención & control , Vacunas contra la COVID-19/efectos adversos , Factor Reumatoide , ARN Mensajero , Vacunación/efectos adversosRESUMEN
Coronavirus disease 2019 (COVID-19) vaccines have been delivered worldwide to prevent the spread of the disease, and almost all Japanese have received the mRNA vaccines "BNT162b2" (Pfizer-BioNTech) or "mRNA-1273" (Moderna). These vaccines have shown efficacy and safety with only minor adverse drug reactions. However, some patients develop severe adverse drug reactions, including autoimmune reactions. In addition, systemic vasculitis, mainly small-vessel vasculitis, following COVID-19 vaccination, has been reported. However, only a few investigators have reported medium-vessel vasculitis following vaccination. We herein report a case of medium-vessel vasculitis presenting with myalgia as the initial clinical manifestation following COVID-19 Moderna vaccination.
Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Vacunas , Vasculitis , Humanos , COVID-19/prevención & control , Vacunas contra la COVID-19/efectos adversos , Mialgia/etiología , Vacunación , Vasculitis/etiologíaRESUMEN
Marginal zone (MZ)-B cells participate in very early immune responses and play a pivotal role in the first-line of defense against blood-borne Ags including bacterial LPS. Since splenic B cells from c-fos transgenic (H2-c-fos) mice are hyper-sensitive to LPS stimulation, we examined LPS-sensitivity of MZ-B cells in the spleen of H2-c-fos mice. Here, we show that proliferation of MZ-B cells from H2-c-fos mice stimulated with LPS was larger than that from control mice. Proliferation and IgM production of the H2-c-fos MZ-B cells were also larger than those of splenic follicular (FO)-B cells from the H2-c-fos mice, suggesting that c-fos overexpression augments LPS-sensitivity of MZ-B cells more than that of FO-B cells. Furthermore, the number of MZ-B cells but not that of FO-B cells in the spleen of H2-c-fos mice was two- to three-fold larger than that in control littermates. The number of transitional type II (T2)-B cells in H2-c-fos mice was also larger than that of control littermates. However, the number of transitional type I (T1)-B cells in the spleen of H2-c-fos mice was not larger than that of control mice. Moreover, this c-fos effect on differentiation of MZ-B cells was intrinsic in B cells by the competitive repopulation assay with hematopoietic stem cells of H2-c-fos and control mice. These results suggest that c-fos overexpression in B cells augments differentiation and accumulation of MZ-B cells.
Asunto(s)
Linfocitos B/inmunología , Linfocitos B/metabolismo , Genes fos , Animales , Linfocitos B/citología , Linfocitos B/efectos de los fármacos , Secuencia de Bases , Diferenciación Celular , Proliferación Celular , ADN Complementario/genética , Proteínas de Unión al ADN/deficiencia , Proteínas de Unión al ADN/genética , Técnicas In Vitro , Lipopolisacáridos/farmacología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Bazo/citologíaRESUMEN
OBJECTIVE: The bcl-6 proto-oncogene is ubiquitously expressed in various tissues. Since we found out the smaller number of TER119(+) cells in the spleen of neonatal bcl-6-deficient (bcl-6(-/-)) mice compared with that of control (bcl-6(+/+)) littermates, we studied functions of bcl-6 in differentiation of erythroid lineage cells. MATERIALS AND METHODS: Erythroblasts in the definitive erythropoiesis were separated into four subsets using anti-TER119 and anti-CD71 mAbs. The cell number and property of these four subsets in spleens of neonatal bcl-6(+/+) and bcl-6(-/-) mice were examined using a flow cytometry. RESULTS: bcl-6 mRNA expression was detected in the TER119(high)CD71(high) subset, which is morphologically equivalent to basophilic erythroblasts, by reverse-transcribed polymerase chain reaction. High percentages of cells in the TER119(low)CD71(high) and TER119(high)CD71(high) subsets were in the cell cycle. The cell number of the TER119(high)CD71(high) subset in the spleen and the percentage of reticulocytes in the peripheral blood of neonatal bcl-6(-/-) mice were significantly lower than those of neonatal bcl-6(+/+) mice. However, the percentage of apoptotic cells and that of cells in the cell cycle in the TER119(high)CD71(high) subset of bcl-6(-/-) mice were similar to those of bcl-6(+/+) mice. CONCLUSION: bcl-6 detected in the TER119(high)CD71(high) subset of erythroblasts in the spleen of neonatal mice may be required to retain the erythroblasts in the cell proliferation stage.
Asunto(s)
Diferenciación Celular , Proteínas de Unión al ADN/fisiología , Eritrocitos/citología , Eritropoyesis , Proteínas Proto-Oncogénicas/fisiología , Factores de Transcripción/fisiología , Animales , Animales Recién Nacidos , Antígenos CD/análisis , Antígenos de Diferenciación de Linfocitos B/análisis , Antígenos de Grupos Sanguíneos/análisis , Proliferación Celular , Proteínas de Unión al ADN/deficiencia , Eritroblastos/citología , Recuento de Eritrocitos , Eritrocitos/fisiología , Ratones , Ratones Noqueados , Proteínas Proto-Oncogénicas/deficiencia , Proteínas Proto-Oncogénicas c-bcl-6 , Receptores de Transferrina , Reticulocitos/citología , Bazo/citología , Factores de Transcripción/deficienciaRESUMEN
Expression of the proto-oncogene c-fos is induced in normal myelopoiesis. However, functions of c-Fos in the process of differentiation towards macrophages are still controversial. To explore the functions, we used the murine myeloblastic leukemia cell line M1. Stimulation of M1 cells with bacterial LPS promotes their terminal differentiation into functional macrophages. Overexpression of c-fos in M1 cells dramatically increased sensitivity of the cells for LPS-induced differentiation and generation of morphologically differentiated cells. However, the overexpression did not modulate phagocytotic functions, surface expression of macrophage markers such as CD16/CD32 (Fcgamma Receptor) and CD54 (ICAM-1), and expression of lysozyme, esterase and c-fms mRNA. Surprisingly, induction of the MHC class II expression on M1 cells after stimulation was inhibited by the overexpression. Expression of CIITA, as an essential transcription factor for the expression, was also reduced in the M1 cells. These results suggest that overexpression of c-fos in differentiating M1 cells perturbs their functional maturation.
Asunto(s)
Diferenciación Celular/genética , Genes fos , Macrófagos , Proteínas Oncogénicas v-fos/biosíntesis , Animales , Diferenciación Celular/efectos de los fármacos , Regulación del Desarrollo de la Expresión Génica , Células Madre Hematopoyéticas/efectos de los fármacos , Antígenos de Histocompatibilidad Clase II/biosíntesis , Antígenos de Histocompatibilidad Clase II/genética , Antígenos de Histocompatibilidad Clase II/inmunología , Lipopolisacáridos/farmacología , Macrófagos/citología , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Ratones , Proteínas Oncogénicas v-fos/genéticaRESUMEN
BACKGROUND: Hematopoietic reconstitution after stem cell transplantation has been analyzed by using stem cells of Ly5 congenic mice. However, the early erythropoiesis has never been analyzed because this marker is not expressed on all of the erythroid lineage cells. The transgenic mouse expressing beta-galactosidase (beta-gal) or green fluorescent protein (GFP) has been reported. Using these markers, we analyzed the early erythropoiesis after stem cell transplantation. METHODS: The beta-gal activity and GFP were examined in the hematopoietic cells of ROSA26 and GFP transgenic mice, respectively, by flow cytometry. The primitive hematopoietic stem cell fraction (Lin(-)c-kit(+)Sca-1(+)) in bone marrow (BM) cells of ROSA26 mice was transferred into lethally irradiated mice. The kinetics of hematopoietic reconstitution was analyzed in the BM and spleen after transplantation. RESULTS: The beta-gal activity, but not the GFP and Ly5, was detected in all of the erythroid (TER119+) cells. The beta-gal activity was also detected in the donor-derived myeloid (Mac-1+), B lymphoid (B220+), and T lymphoid (Thy-1+) cells in the BM and spleen after stem cell transplantation. The kinetics of the hematopoietic reconstitution demonstrated that early erythroid (TER119(low)CD71(med)) cells were developed in the BM and spleen within 2 days after transplantation before development of proerythroblasts (TER119(+)CD71(high)), and that massive erythropoiesis and myelopoiesis were observed in the spleen until 2 and 4 weeks after transplantation, respectively. Conclusions. The beta-gal of ROSA26 mice can be a useful marker to identify the donor-derived hematopoietic cells, including early erythroid cells, and the first major wave of erythropoiesis occurring in the spleen after stem cell transplantation.
Asunto(s)
Eritropoyesis , Trasplante de Células Madre Hematopoyéticas , Proteínas/fisiología , beta-Galactosidasa/análisis , Animales , Antígenos CD/análisis , Antígenos de Diferenciación de Linfocitos B/análisis , Antígenos de Grupos Sanguíneos/análisis , Células de la Médula Ósea/fisiología , Ratones , Ratones Endogámicos C57BL , ARN no Traducido , Receptores de Transferrina , Bazo/citologíaRESUMEN
Expression of B lymphocyte-induced maturation protein 1 (Blimp-1) transcription factor is essential for promoting B cell differentiation into plasma cells. However, a critical transcription factor for Blimp-1 expression in activated B cells is unclear. When splenic B cells were stimulated with CD40 ligand (CD40L) and IL-4, terminal differentiation was induced in the B cells from c-fos transgenic (H2-c-fos) mice but barely in those from control littermates and from c-fos-deficient mice. AP-1 family and Blimp-1 mRNAs were transiently induced in the control B cells, and overexpression of c-Fos induced a sufficient amount of Blimp-1 for terminal differentiation in the H2-c-fos B cells. When normal and c-fos-deficient B cells were stimulated with LPS, a sufficient amount of Blimp-1 for terminal differentiation was induced in those B cells. However, expression of c-fos/AP-1 family mRNAs in LPS-stimulated normal B cells was similar to that of normal B cells stimulated with CD40L and IL-4. EMSA and chromatin immunoprecipitation assays using the AP-1-binding DNA sequence in the murine Blimp-1 promoter region demonstrated that AP-1-binding activity in nuclear protein of LPS-stimulated normal B cells was prolonged more than that in normal B cells stimulated with CD40L and IL-4. Furthermore, the percentage of CD138(+) B cells within germinal center B cells in the spleen and the number of Ab-forming cells in the bone marrow of H2-c-fos mice was larger than that of control mice 12 days after immunization. Thus, although c-Fos is not essential for Blimp-1 expression, c-Fos/AP-1 positively regulates Blimp-1 expression and terminal differentiation of activated B cells.
Asunto(s)
Linfocitos B/citología , Diferenciación Celular/inmunología , Proteínas Proto-Oncogénicas c-fos/fisiología , Factor de Transcripción AP-1/fisiología , Adyuvantes Inmunológicos/fisiología , Animales , Linfocitos B/inmunología , Ligando de CD40/farmacología , Proliferación Celular , Células Cultivadas , Epítopos de Linfocito B/inmunología , Interleucina-4/farmacología , Lipopolisacáridos/farmacología , Activación de Linfocitos/genética , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Factor 1 de Unión al Dominio 1 de Regulación Positiva , Proteínas Proto-Oncogénicas c-fos/biosíntesis , Proteínas Proto-Oncogénicas c-fos/deficiencia , Proteínas Proto-Oncogénicas c-fos/metabolismo , Proteínas Represoras/biosíntesis , Bazo/citología , Bazo/inmunología , Factores de Tiempo , Factor de Transcripción AP-1/biosíntesis , Factor de Transcripción AP-1/metabolismo , Factores de Transcripción/biosíntesisRESUMEN
Clast5/Stra13/DEC1 is a member of the helix-loop-helix family of transcriptional repressors. We have previously shown that Clast5 is rapidly down-regulated upon B cell activation and its overexpression inhibits cell cycle progression in B lymphoma cells. In the present study, we show that Clast5 expression is developmentally regulated during B cell differentiation, being expressed at the progenitor B cells, down-regulated at the precursor B cells, elevated in immature and mature resting B lymphocytes, and down-regulated again in germinal center B cells. To investigate the function of Clast5 in regulating lymphocyte development, we have generated transgenic mice expressing Clast5 in B- and T-lineage cells (Clast5-Tg). Clast5-Tg mice grew and bred normally but their spleen and thymus cellularity was reduced compared with control littermates. The development of B cells in the bone marrow and T cells in the thymus was impaired, with the expansion of progenitor B and T cells most strongly affected. The frequency of IL-7-responsive cells in the bone marrow of Clast5-Tg mice was reduced by >80% and their proliferative response to IL-7 was also compromised. Mature B cells from Clast5-Tg mice were hyporesponsive to antigen receptor cross-linking and exhibited mild reduction in the proliferative response to CD40 ligation or lipopolysaccharide stimulation. Moreover, the development of germinal center B cells and antibody production against a T-dependent antigen were reduced in Clast5-Tg mice. These results reveal a critical role for Clast5/Stra13/DEC1 in negatively regulating lymphocyte development and function in vivo.