RESUMO
Undifferentiated Nasopharyngeal Carcinoma (UNPC) is associated with Epstein-Barr Virus (EBV) and characterized by an abundant immune infiltrate potentially influencing the prognosis. Thus, we retrospectively assessed the significance of immunosuppression in the UNPC microenvironment as prognostic biomarker of treatment failure in a non-endemic area, and monitored the variation of systemic EBV-specific immunity before and after chemoradiotherapy (CRT). DNA and RNA were extracted from diagnostic biopsies obtained by tumor and adjacent mucosa from 63 consecutive EBV+ UNPC patients who underwent radical CRT. Among these patients 11 relapsed within 2 years. The expression of the EBV-derived UNPC-specific BARF1 gene and several immune-related genes was monitored through quantitative RT-PCR and methylation-specific PCR analyses. Peripheral T cell responses against EBV and BARF1 were measured in 14 patients (7 relapses) through IFN-γ ELISPOT assay. We found significantly higher expression levels of BARF1, CD8, IFN-γ, IDO, PD-L1, and PD-1 in UNPC samples compared to healthy tissues. CD8 expression was significantly reduced in both tumor and healthy tissues in UNPC patients who relapsed within two years. We observed a hypomethylated FOXP3 intron 1 exclusively in relapsed UNPC patients. Finally, we noticed a significant decrease in EBV- and BARF1-specific T-cells after CRT only in relapsing patients. Our data suggest that a high level of immunosuppression (low CD8, hypomethylated FoxP3) in UNPC microenvironment may predict treatment failure and may allow an early identification of patients who could benefit from the addition of immune modulating strategies to improve first line CRT.
Assuntos
Antígenos CD8/imunologia , Resistencia a Medicamentos Antineoplásicos/imunologia , Fatores de Transcrição Forkhead/imunologia , Carcinoma Nasofaríngeo/imunologia , Neoplasias Nasofaríngeas/imunologia , Tolerância a Radiação/imunologia , Adolescente , Adulto , Idoso , Quimiorradioterapia/métodos , Metilação de DNA , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/imunologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Carcinoma Nasofaríngeo/terapia , Neoplasias Nasofaríngeas/terapia , Valor Preditivo dos Testes , Estudos Retrospectivos , Microambiente Tumoral/imunologia , Proteínas Virais/imunologia , Adulto JovemRESUMO
Signal joint T cell receptor excision circles (sjTRECs) have been reported as a clinical marker to measure the potential for recovery of the immune system after immunosuppressive treatments. The aim of this study was to investigate the thymic regenerative potential in 55 human immunodeficiency virus (HIV)-1 infected (HIV(+)) and non-infected (HIV(-)) lymphoma patients, candidates for autologous stem cell transplantation (ASCT). Moreover, the possible associations between sjTRECs and other immunological and clinical parameters were examined. SjTRECs levels in peripheral blood mononuclear cells (PBMCs) were quantified by real-time polymerase chain reaction and T lymphocyte subsets were analysed by flow cytometry. Our data showed that sjTRECs were reduced in lymphoma patients compared to healthy controls, although a weak significant association between low sjTRECs levels and increasing age was maintained [odds ratio (OR) = 4.00; 95% confidence interval (CI) 1.09-17.17]. We found that different chemotherapeutic treatments seem to induce similar effects on the thymic reservoir, independently from their intensity (type and number of cycles of previous chemotherapy). Results from multivariate models including adjustment for patients' sex, type of lymphoma and type of chemotherapy showed that thymic output was independent from HIV infection (OR, 0.95; 95% CI 0.20-4.48). SjTRECs levels correlated with naive T cell subsets in overall lymphoma patients and after stratification by HIV infection (r > 0.37). HIV replication should be maximally suppressed to properly evaluate thymic output by sjTREC markers. Our results suggested that de novo T cell generation is maintained partially in pretreated recurrent lymphoma patients, candidates for ASCT, and could contribute to restore the immune function after transplantation.
Assuntos
Reparo do DNA/genética , DNA Circular , Infecções por HIV/imunologia , HIV-1 , Linfoma Relacionado a AIDS/imunologia , Linfócitos T/imunologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Fármacos Anti-HIV/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Terapia Antirretroviral de Alta Atividade , Relação CD4-CD8 , Estudos de Casos e Controles , Ciclofosfamida/uso terapêutico , Doxorrubicina/uso terapêutico , Feminino , Citometria de Fluxo , Rearranjo Gênico do Linfócito T/genética , Marcadores Genéticos , Infecções por HIV/tratamento farmacológico , Infecções por HIV/terapia , Humanos , Linfoma Relacionado a AIDS/tratamento farmacológico , Linfoma Relacionado a AIDS/terapia , Masculino , Pessoa de Meia-Idade , Razão de Chances , Transplante de Células-Tronco de Sangue Periférico , Prednisona/uso terapêutico , Prognóstico , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Risco , Transplante Autólogo , Vincristina/uso terapêutico , Replicação ViralRESUMO
A large number of evidences indicate that progression of HIV disease is driven by an increase in viral burden. It is still unclear, however, to what extent this is contributed by the dysregulation of the molecular mechanisms governing virus gene expression at the transcriptional or posttranscriptional levels. To address this issue, several quantitative virologic parameters (including provirus transcriptional activity and splicing pattern) were analyzed in individuals with nonprogressive HIV infection and compared with those of a matched group of progressor patients. Exact quantification was achieved by a competitive PCR procedure using a multicompetitor template. Nonprogressors were characterized by striking differences in the levels of viremia, provirus copy number, and overall levels of all viral mRNA classes in peripheral blood mononuclear cells. Additionally, the transcriptional activity of the proviral DNA in these patients was mainly engaged in the production of multiprocessed transcripts, with a pattern resembling the early phases of the experimental infection. Taken together, these results show that both viral load and provirus transcription pattern are remarkably different in infected individuals nonprogressing toward overt disease, and further support the notion that disease progression is accompanied by a change in the kinetics of HIV gene expression.
Assuntos
Regulação Viral da Expressão Gênica , Infecções por HIV/genética , HIV-1/genética , RNA Mensageiro/metabolismo , RNA Viral/metabolismo , Ativação Transcricional , Adulto , Feminino , Infecções por HIV/virologia , Humanos , Masculino , Reação em Cadeia da Polimerase , Carga Viral , Viremia/genéticaRESUMO
HIV infection is characterized by the reduction of the CD4+, CD45RA+, CD26+, and CD28+ lymphocyte subsets and of the in vitro production of IL-2, IL-4, and interferon-gamma; on the contrary, chemokine production is usually increased. These abnormalities are only partially restored by antiretroviral chemotherapy. Therapy with interleukin-2 has been proposed to restore the functions of the immune system, but the mechanisms by which IL-2 exerts its activities are unknown. The aim of this study was to define the effects of rIL-2 administration on CD4+, CD45RA+, CD45R0+, and CD26+ lymphocytes and on the in vitro production of IL-2, IL-4, IL-10, IFN-gamma, RANTES, and sCD30 in HIV+ patients. 10 HIV+ patients with CD4 cell counts between 200 and 500 cells/mm3 were treated with six cycles of subcutaneous recombinant IL-2 administration, in combination with zidovudine and didanosine. This therapeutic regimen resulted in a remarkable increase in the number of CD4+ cells and in the prolonged reduction of the levels of viremia. CD45R01 cells were expanded during the first cycle of therapy, while CD45RA+/CD26+ cells predominated after the third cycle. At this time, the in vitro production of IL-2, IL-4, IFN-gamma, and sCD30 were significantly upregulated. These results demonstrate that rIL-2 in HIV+ patients induces the reconstitution of the CD4/CD45RA lymphocytes subtype. This expanded cell population recovered the ability to produce in vitro IL-2, IL-4, and IFN-gamma. These effects may be beneficial to HIV+ patients by improving their immune response to microorganisms or vaccines.
Assuntos
Linfócitos T CD4-Positivos/efeitos dos fármacos , Citocinas/biossíntese , Infecções por HIV/imunologia , Infecções por HIV/terapia , Interleucina-2/uso terapêutico , Contagem de Linfócito CD4 , Linfócitos T CD8-Positivos/efeitos dos fármacos , Células Cultivadas , Quimiocina CCL5/biossíntese , Dipeptidil Peptidase 4/imunologia , Infecções por HIV/sangue , Infecções por HIV/virologia , Humanos , Injeções Subcutâneas , Interferon gama/biossíntese , Interleucina-10/biossíntese , Interleucina-4/biossíntese , Antígeno Ki-1/biossíntese , Antígenos Comuns de Leucócito/imunologia , Proteínas Recombinantes/uso terapêutico , Viremia/imunologia , Viremia/terapiaRESUMO
Type VI collagen, a ubiquitous extracellular cell adhesion molecule, is formed by heterotrimeric monomers which associate into dimers and tetramers and assemble into larger oligomers constituting the 100 nm-long periodic microfilaments of connective tissues. One distinctive structural characteristic of type VI collagen is represented by an alpha 3 chain with a much larger molecular mass compared to the other two chains and with an extensive size heterogeneity, exemplified by the separation into up to five polypeptides in SDS-PAGE. There is evidence that the alpha 3(VI) mRNA can undergo alternative splicing of three VWFA modules at the 5'-end, potentially resulting in the expression of protein variants. Here we report that alternative splicing of alpha 3(VI) mRNA in chicken embryo did not result in the absolute predominance of a particular alpha 3(VI) form in any tissue; instead, the expression of variants including exons A9, A8 and A6 increased with age. In addition, these variants had a more restricted tissue distribution pattern compared to variants including only constitutive exons: A9+ were the rarest and were present almost exclusively in skin and skeletal muscle; A6+ were expressed in several of the examined tissues with local variations; A8+ had intermediate levels and were less widely distributed than A6+ variants. Quantitative densitometric scanning of immunoblots of type VI collagen purified from gizzard and stained with VWFA module-specific antibodies indicated that the polymorphic migration pattern of alpha 3(VI) polypeptides is contributed by concurrent or independent splicing of two exons (A8 and A6) and probably by processing and/or proteolysis at the N- and C-terminus. Three exon-specific recombinant polypeptides were examined in cell adhesion assays, and A6 appeared to be the most active, particularly at low substrate concentrations. The adhesion to the recombinant modules was not abrogated by EDTA nor by mAbs against the integrin beta 1 or alpha 2 subunits. Over all, these results suggest that the splicing of the alpha 3(VI) mRNA and the tissue distribution pattern of type VI collagen variants, apart from promoting cell adhesion to different extents, might also affect additional structural as well as functional properties of this molecule, including microfilament formation and interaction with other extracellular matrix molecules.
Assuntos
Processamento Alternativo , Adesão Celular , Colágeno/genética , Fator de von Willebrand/biossíntese , Animais , Anticorpos Monoclonais/metabolismo , Embrião de Galinha , Colágeno/biossíntese , Colágeno/imunologia , Técnica Indireta de Fluorescência para Anticorpo , Hibridização In Situ , Camundongos , Camundongos Endogâmicos BALB C , RNA Mensageiro/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Ribonucleases/metabolismo , Fator de von Willebrand/genéticaRESUMO
Evidence suggests that CD8+ lymphocytes are involved in the control of Human Immunodeficiency virus type 1 (HIV-1) infection by the release of HIV-suppressive factors. The human chemokines RANTES and the macrophage inflammatory protein 1 alpha (MIP-1 alpha) have been identified to be potent inhibitors of HIV in vitro. The aim of this study was to determine whether high levels of these chemokines are associated with a delayed progression of HIV disease. We have therefore analysed the in vitro production of RANTES and MIP-1 alpha from purified stimulated CD8+ cells from HIV+ long term survivors (LTS) and, as a comparison, from HIV+ patients with progressive disease. RANTES production was similar in LTS and progressors (14.06 +/- 3, 13.36 +/- 4.1 ng/ml, not statistically significant); the same cells from healthy controls show a RANTES production of 20 +/- 3.5 ng/ml (P = 0.034 versus LTS and P = 0.038 versus progressors). MIP-1 alpha production was slightly reduced in LTS (96.8 +/- 12 ng/ml) and progressors (91.6 + 17, not statistically significant between the two groups) when compared to healthy controls (109 +/- 7 ng/ml, P = 0.03). Our study suggests that resistance to HIV-1 progression in LTS may not be associated with high levels of RANTES and MIP-1 alpha production.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Quimiocina CCL5/biossíntese , Infecções por HIV/imunologia , HIV-1 , Proteínas Inflamatórias de Macrófagos/biossíntese , Adulto , Contagem de Linfócito CD4 , Quimiocina CCL3 , Quimiocina CCL4 , Progressão da Doença , Feminino , Humanos , Antígenos Comuns de Leucócito/biossíntese , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Proteína Tirosina Fosfatase não Receptora Tipo 1 , Sobreviventes , Subpopulações de Linfócitos T/imunologiaRESUMO
Six patients with human immunodeficiency virus (HIV)-associated non-Hodgkin lymphoma receiving chemotherapy (CT) with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus granulocyte colony-stimulating factor were sequentially monitored to study the effects of these treatments on their immunologic status (CD4 and CD8 cell counts) and on HIV plasma viremia. We show that mean CD4 cell counts declined significantly after the third cycle of CT (187 +/- 117/microliters before CT versus 92.4 +/- 60/microliters; p = 0.04) and remained significantly reduced 4 months after completion of CT. Modifications of CD8 cell counts were not statistically significant. The effects of CT on plasma viremia, as measured by a competitive polymerase chain reaction technique, were delayed until the fourth cycle, when an increase of viral load ranging from 0.6 to 2 logs (p = 0.027) was observed. After this point, viremia returned to baseline levels, with the exception of two patients who later developed opportunistic infections and one who underwent disease progression. These results suggest that, contrary to CD4 cell counts, plasma viremia could be a faithful surrogate marker for monitoring of HIV disease progression in patients undergoing CT.
Assuntos
Antineoplásicos/uso terapêutico , Ciclofosfamida/uso terapêutico , Doxorrubicina/uso terapêutico , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Soropositividade para HIV/complicações , Linfoma não Hodgkin/tratamento farmacológico , Prednisona/uso terapêutico , Vincristina/uso terapêutico , Contagem de Linfócito CD4 , Antígenos CD8/análise , Ensaios Clínicos Fase III como Assunto , Proteína do Núcleo p24 do HIV/genética , Soropositividade para HIV/imunologia , Soropositividade para HIV/virologia , HIV-1/isolamento & purificação , Humanos , Linfoma não Hodgkin/complicações , Linfoma não Hodgkin/imunologia , Linfoma não Hodgkin/virologia , Estudos Multicêntricos como Assunto , RNA Viral/sangue , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
The association of antiretroviral agents plus interleukin 2 (IL-2) represents an efficient approach to the treatment of HIV+ subjects. While the effects of IL-2 on the immune system have been investigated, little is known concerning its impact on HIV dynamics. Two antiretroviral drugs control HIV viremia, but have minimal effects on the proviral load, a predictor of disease progression and response to therapy. The aim of this study was to define the effect of rIL-2 on HIV proviral copy numbers and its relationship to changes in CD4+ and CD8+ subsets. Twelve HIV+ patients with CD4 cell counts between 200 and 500 cells/mm3 were treated with six cycles of subcutaneous rIL-2, in combination with zidovudine and didanosine. This regimen resulted in a rapid and durable decrease in proviral load in the peripheral blood, in an increase in CD8+ lymphocytes, and in the emergence of a CD4+CD45RA+ T subset. These results demonstrate that the rationale for IL-2 administration to HIV+ patients may depend not only on its effects on the immune system, but also on the reduction of the number of infected cells, reinforcing the notion that IL-2 can have a favorable impact on the natural history of HIV infection.
Assuntos
Síndrome da Imunodeficiência Adquirida/virologia , HIV/efeitos dos fármacos , Interleucina-2/farmacologia , Provírus/efeitos dos fármacos , Subpopulações de Linfócitos T/efeitos dos fármacos , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Síndrome da Imunodeficiência Adquirida/imunologia , Adulto , Fármacos Anti-HIV/uso terapêutico , Relação CD4-CD8 , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/efeitos dos fármacos , Didanosina/uso terapêutico , Feminino , Humanos , Masculino , Reação em Cadeia da Polimerase , Provírus/isolamento & purificação , Proteínas Recombinantes/farmacologia , Carga Viral , Zidovudina/uso terapêuticoRESUMO
Interleukin-2 has been widely used in HIV-1+ subjects as an immunoactivating agent. In this study, we investigated cytokine production, Ki67 antigen expression and the modulation of the surface phenotype of the CD4/CD25+ subset as compared to the reciprocal CD4/CD25- subset in IL-2-treated HIV+ patients. Our findings suggest that CD4 T cells are heterogeneous in responding to IL-2, because CD4/CD25+ cells sharply increased their "memory" phenotype, their Ki67 antigen expression and were the main in vivo targets for IL-2-dependent proliferation during therapy, while the percentages of IFN-gamma+ (terminally differentiated) cells remained unchanged at the end of therapy. Conversely, the CD4+/CD25- subpopulation showed an expansion of differentiated cells and a slight increase in the proliferation rate. The use of anti-retroviral therapy alone (HAART) reduced the proliferation and increased the differentiation of both CD4 subsets. Our data suggest that IL-2 has a moderate capacity to activate resting T cells in vivo and is probably unable to boost HIV-1 from latency to the replicative state.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/patologia , Citocinas/efeitos dos fármacos , Infecções por HIV/tratamento farmacológico , Interleucina-2/farmacologia , Adulto , Fármacos Anti-HIV/administração & dosagem , Terapia Antirretroviral de Alta Atividade , Contagem de Linfócito CD4 , Linfócitos T CD4-Positivos/metabolismo , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Divisão Celular/fisiologia , Citocinas/biossíntese , Infecções por HIV/imunologia , Humanos , Indinavir/administração & dosagem , Interferon gama/biossíntese , Interferon gama/efeitos dos fármacos , Interleucina-2/administração & dosagem , Interleucina-2/análogos & derivados , Interleucina-2/uso terapêutico , Receptores de Interleucina-2/metabolismo , Proteínas Recombinantes/administração & dosagemRESUMO
The initial idea that potent antiretroviral therapies could eradicate HIV infection within a few years of treatment has been recently challenged by the demonstration that the viral reservoir persists in the peripheral blood and in the lymphoid tissue. For this reason, an alternative approach based on the use of interleukin-2 has been developed. This cytokine, in fact, may be able to activate infected cells, promoting viral integration and replication, making HIV susceptible to antiretroviral treatments; this fact may ultimately contribute to the eradication of the virus itself. The measurement of the viral reservoir appears therefore essential to monitor the effects of combination therapies. We summarize here the technical approaches that have been used to quantitatively assess the HIV reservoir. We also show that the prolonged use of IL-2 in association with antiretroviral drugs promotes a reduction of the viral reservoir, but is unable to eradicate HIV, even after two years of therapy. The available in vitro and in vivo data do not exclude the fact that IL-2 may have a future in the treatment of HIV infection, though new therapeutic approaches using different strategies are required to clarify this issue.
Assuntos
Infecções por HIV/tratamento farmacológico , HIV/isolamento & purificação , Interleucina-2/uso terapêutico , Terapia Antirretroviral de Alta Atividade , Contagem de Linfócito CD4 , DNA Viral/análise , Infecções por HIV/imunologia , Infecções por HIV/virologia , HumanosAssuntos
Didanosina/uso terapêutico , Infecções por HIV/tratamento farmacológico , Hidroxiureia/uso terapêutico , Contagem de Linfócito CD4 , Didanosina/administração & dosagem , Didanosina/efeitos adversos , Quimioterapia Combinada , Humanos , Hidroxiureia/administração & dosagem , RNA Viral/sangue , Resultado do Tratamento , Viremia/tratamento farmacológico , Zidovudina/uso terapêuticoAssuntos
Fármacos Anti-HIV/uso terapêutico , Didanosina/uso terapêutico , Infecções por HIV/tratamento farmacológico , Interleucina-2/uso terapêutico , Viremia/tratamento farmacológico , Zidovudina/uso terapêutico , Fármacos Anti-HIV/administração & dosagem , Contagem de Linfócito CD4 , Didanosina/administração & dosagem , Quimioterapia Combinada , Feminino , HIV/isolamento & purificação , Infecções por HIV/imunologia , Humanos , Interleucina-2/administração & dosagem , Antígenos Comuns de Leucócito/análise , Antígenos Comuns de Leucócito/imunologia , Masculino , Projetos Piloto , RNA Viral/sangue , Viremia/imunologia , Zidovudina/administração & dosagemRESUMO
Despite its potent antiviral activity, highly active antiretroviral therapy (HAART) only exerts a marginal effect on CD4+ T-cell regeneration in HIV-infected subjects. Combination therapies aimed at boosting T-cell activity and maturation may provide an important contribution to the restoration of immune function. Here, we report the results obtained by a two-year follow-up of a cohort of HIV-infected patients treated with a combination of HAART and interleukin-2 (IL-2). In these patients, in addition to a series of quantitative virological and immunological parameters, we investigated T-cell regeneration by an immunophenotypic assay monitoring CD4+ naïve T cells, and by analysis of thymic function, through the quantification of the excision DNA products of T-cell receptor rearrangement (TRECs) in lymphocytes. Compared with HAART alone, we found that the IL-2 combination therapy was equally effective in reducing the levels of viremia and marginally more effective in decreasing proviral DNA load. Strikingly, the IL-2 combination produced a marked increase in the number of CD4+ T cells bearing a naïve phenotype (CD45RA+, CD62L+), which was apparent for over 96 weeks after therapy. To assess whether these cells were the product of improved T-cell generation, we exploited a competitive quantitative molecular assay to quantify TRECs in peripheral blood lymphocytes. Surprisingly, we found that the levels of these molecules were unchanged in these patients. These findings indicate that improved thymic function does not account for the early rise of CD4 naïve cells in HIV-positive patients treated with IL-2, and suggest that alternative mechanisms of T-cell maturation and differentiation are responsible for this event.
Assuntos
Terapia Antirretroviral de Alta Atividade , Soropositividade para HIV/tratamento farmacológico , Soropositividade para HIV/imunologia , Interleucina-2/uso terapêutico , Timo/imunologia , Adulto , Relação CD4-CD8 , DNA Viral/sangue , Rearranjo Gênico do Linfócito T , Humanos , Pessoa de Meia-Idade , Provírus/genética , RNA Viral/sangue , Ensaios Clínicos Controlados Aleatórios como Assunto , Subpopulações de Linfócitos T , Carga ViralRESUMO
The amino- and carboxyl-terminal globular domains of type VI collagen are composed of several homologous modules similar to the type A collagen-binding modules present in von Willebrand factor. The human alpha 3(VI) chain that contributes most of the amino-terminal globule appears heterogeneous in size as a result of alternative splicing of two exons (Stokes D. G., Saitta, B., Timpl, R., and Chu, M.-L. (1991) J. Biol. Chem. 266, 8626-8633). In the present study, we report a further characterization of the 5'-end of the gene of the human alpha 3(VI) chain and show that transcription initiates at multiple sites. Southern blotting and DNA sequencing indicate that there is an additional type A exon (A9/N10) at about 1.8 kilobase pairs downstream of the exon coding for the signal peptide. The open reading frame of this additional exon reveals 1 cysteine and three potential N-glycosylation sites. Polymerase chain reaction, Northern blotting, and RNase protection assays demonstrate that exon A9/N10 is subject to alternative splicing in normal and tumor cell lines and that this generates more protein variants of the alpha 3(VI) chain than expected before. A comparison with the corresponding amino-terminal globule of the chicken alpha 3(VI) chain shows the presence of 1 additional cysteine in this portion of the molecule and suggests that human type VI collagen has more possibilities for structural and functional variations compared to chicken type VI collagen.
Assuntos
Processamento Alternativo , Colágeno/genética , Éxons , Genes , Variação Genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Southern Blotting , Galinhas , Colágeno/análise , DNA de Neoplasias/genética , DNA de Neoplasias/isolamento & purificação , Imunofluorescência , Biblioteca Genômica , Glioma , Humanos , Substâncias Macromoleculares , Dados de Sequência Molecular , Reação em Cadeia da Polimerase/métodos , Proteínas Recombinantes de Fusão/análise , Sequências Repetitivas de Ácido Nucleico , Mapeamento por Restrição , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico , Transcrição Gênica , Células Tumorais Cultivadas , beta-Galactosidase/análise , beta-Galactosidase/genéticaRESUMO
BACKGROUND: Interleukin-2 (IL-2) has been used successfully to increase CD4 cell counts in patients who are human immunodeficiency virus (HIV) positive. The mechanisms involved in this phenomenon are unknown. We hypothesized that a differential proliferation rate of CD4+ compared with CD8+ lymphocytes could be related to the increase of CD4 counts and of CD4/CD8 ratios that occur in HIV+ patients during IL-2 treatment. METHODS: We enrolled in our study 14 HIV+ patients treated with IL-2 or with highly active antiretroviral therapy (HAART) during a 96-week observation period. Using flow cytometry, we measured longitudinally the expression of the Ki67 antigen in peripheral blood CD4+ and CD8+ lymphocyte subsets. RESULTS: Compared with HAART alone, IL-2 produced a rapid increase of Ki67+ proliferating CD4 cells and a concomitant increase of the CD4/CD8 ratios, whereas the corresponding CD8 proliferation increased slightly. On the contrary, HAART alone was effective in suppressing equally both CD4 and CD8 proliferation. CONCLUSIONS: Our results suggest a selective activity of IL-2 on CD4 T-cell proliferation; on the contrary, CD8-specific proliferation is affected minimally during treatment. This information may offer the potential to plan correctly immune activating regimens.
Assuntos
Terapia Antirretroviral de Alta Atividade , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Infecções por HIV/tratamento farmacológico , Interleucina-2/uso terapêutico , Apoptose/efeitos dos fármacos , Relação CD4-CD8 , Divisão Celular/imunologia , Quimioterapia Combinada , Citometria de Fluxo , Humanos , Imunoterapia , Antígeno Ki-67/metabolismoRESUMO
In most HIV-1-infected patients, clinical and immunological progression develops within a few years. Few infected people, termed long-term non-progressors (LTNP), remain healthy and immunologically stable for a long time. The factors governing the maintenance of this condition are not well known, but it is conceivable that CD8+ lymphocytes, cells that play a central role in controlling in vitro HIV replication, may have a part in vivo in this process. The aim of this study was to characterize the phenotypic profile and the cytokine production of CD8+ cells in a group of LTNP patients who had stable CD4+ cell counts (> 500/mm3) for at least 7 years. Their CD8+ absolute numbers were similar to a control group composed of HIV-1+ patients who have a progressive decline of their CD4+ cell counts. However, our multiparameter immunofluorescence studies show that a clinical and immunologically stable condition is associated with the presence of a CD28+, CD95 strongly positive CD8+ population, while disease progression is marked by the CD28-CD95+CD8+ subset. Purified CD8+ cells from LTNP retain their ability to produce IL-2, interferon-gamma (IFN-gamma) and, to a lesser degree, to produce IL-10 and IL-4. In contrast, CD8+ cells from progressors are unable to secrete IL-2 and IL-10. Although CD8+ cytokine profile does not fit with the proposed T helper (Th)1/Th2 switch in progressive HIV infection, LTNP CD8+ T cells maintain their capacity to produce IL-2 and IL-10 (Th0-like), a pattern very similar to that observed in normal HIV healthy controls. We suggest that CD8+ cells expressing CD28, CD95 and having a Th0-like profile may be considered to be associated with long-term survival.
Assuntos
Síndrome da Imunodeficiência Adquirida/imunologia , Linfócitos T CD8-Positivos/imunologia , Citocinas/biossíntese , HIV-1 , Adulto , Antígenos CD28/análise , Feminino , Humanos , Imunofenotipagem , Masculino , Receptor fas/análiseRESUMO
To assess the efficacy of the therapeutic use of inhibitors of ribonucleotide reductase for the treatment of human immunodeficiency virus (HIV) type 1 infection, 7 consecutive patients were enrolled in a clinical trial involving monotherapy with hydroxyurea for 8-19 weeks. During therapy, patients were evaluated for clinical status and immunologic, hematologic, and quantitative virologic parameters, including determinations of viremia and the number of provirus-containing cells by competitive polymerase chain reaction. In all patients, these parameters were not modified during the course of therapy. The number of CD4 cells remained generally unchanged or showed a tendency to further decline. No sign of improvement in HIV disease was detected in any patient. These observations indicate that monotherapy with hydroxyurea does not provide therapeutic benefit to HIV-1-infected patients.