Assuntos
Ciclina D1 , Humanos , Ciclina D1/genética , Rearranjo Gênico , Masculino , Linfoma de Células B/genética , Linfoma de Células B/patologia , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/patologia , Pessoa de Meia-Idade , Hibridização in Situ Fluorescente , Feminino , IdosoRESUMO
OBJECTIVE: Obesity is a risk factor for developing venous thromboembolism (VTE). Optimal dosage of enoxaparin has not been established in the obese population. We aimed to study clinical outcomes and complications with enoxaparin in obese patients. METHODS: A retrospective, single centre observational study of obese patients treated with enoxaparin for VTE (n = 47) using a body mass index (BMI)-stratified dosing, thromboprophylaxis (n = 46), and non-obese controls (n = 20) was performed. Anti-Xa was used to measure enoxaparin efficacy. RESULTS: Patients with a median BMI of 36.3 kg/m2 (range 30-52.7) with a median weight of 136 kg (range 68-240) received therapeutic enoxaparin at median 120 mg BID (range 60-200). A median targeted anti-Xa level of 0.79 (95% CI 0.72-1.03) IU/mL was achieved in 58% of patients. Dose reduction, or increase was needed in 25%, and 16% patients respectively. Mild or major haemorrhage, or VTE occurred in 10%, 2% and 2% patients respectively. Patients with a median weight of 160 kg (range 130-245) received thromboprophylaxis with 40 mg BID enoxaparin. Targeted median anti-Xa of 0.22 IU/mL (95% CI 0.19-0.24) was achieved in 59% patients. Mild haemorrhage was seen in 2%, while none developed major haemorrhage or VTE. Control patients who received enoxaparin 40 mg daily did not develop VTE; 5% had minor bleeding events. CONCLUSIONS: BMI-stratified therapeutic enoxaparin dosing regimen is safe and effective therapy in obese patients. Fixed dosing without monitoring may not be appropriate. Thromboprophylaxis with 40 mg BID in obese patients was efficacious in preventing VTE without excess bleeding compared to control patients.
RESUMO
A 59-year-oldwoman presented with a 2-month history of malaise, abdominal distention and unintentional weight loss. She was initially managed as community acquired pneumonia with a suspicion of underlying chronic liver disease but she deteriorated rapidly into a multiorgan failure necessitating transfer to intensive care unit of a tertiary hospital. She was investigated with liver and bone marrow biopsy that confirmed the diagnosis of hepatosplenic T cell lymphoma. She was treated with cyclophosphamide, doxorubicin, vincristine, etoposide and prednisolone chemotherapy that was changed to salvage ifosfamide carboplatin etoposide (ICE) chemotherapy due to poor response with first-line chemotherapy and disease progression. Unfortunately, her disease progressed further and she opted for palliative management.
Assuntos
Neoplasias Hepáticas/complicações , Linfoma de Células T/complicações , Insuficiência de Múltiplos Órgãos/etiologia , Neoplasias Esplênicas/complicações , Feminino , Humanos , Pessoa de Meia-IdadeAssuntos
Antirretrovirais/efeitos adversos , DNA Mitocondrial/efeitos dos fármacos , Infecções por HIV/patologia , Hemangioma/patologia , Mitocôndrias/efeitos dos fármacos , Neoplasias Cutâneas/patologia , Adipócitos/efeitos dos fármacos , Adipócitos/patologia , DNA Mitocondrial/análise , Infecções por HIV/tratamento farmacológico , Humanos , Masculino , Pessoa de Meia-Idade , Mitocôndrias/ultraestrutura , Tela Subcutânea/patologiaRESUMO
BACKGROUND: Abacavir hypersensitivity in genetically susceptible individuals implicates an abacavir-specific T-cell response to either the parent drug or a metabolite generated in vivo. We have analysed the cytokine profile in antigen-presenting cells and the T-lymphocytes that are involved in the pathological immune response to abacavir. METHODS: In this study, we compared abacavir-specific cytokine responses in cultured peripheral blood mononuclear cells (PBMCs) from HIV-infected abacavir hypersensitive, tolerant and naive individuals. Cells were cultured in the presence or absence of abacavir. Cytokine expression was determined by microarray analysis, enzyme-linked immunosorbent assays and flow cytometry. RESULTS: We demonstrated using in vitro models of immune activation that the production of interferon-gamma was specifically induced by abacavir treatment in PBMCs obtained from hypersensitive patients carrying the HLA-B*5701 allele (median 123.86 compared with -30.83 for tolerant controls, P=0.001). CONCLUSION: These results provide further insight into the immunological and metabolic basis of abacavir hypersensitivity syndrome. In vitro assays could assist in the identification of susceptible loci by providing a surrogate marker for the hypersensitivity reaction. Such a marker could be studied in unexposed individuals to shed further light on the immunopathogenesis of the abacavir hypersensitivity syndrome.
Assuntos
Fármacos Anti-HIV/efeitos adversos , Citocinas/metabolismo , Didesoxinucleosídeos/efeitos adversos , Hipersensibilidade a Drogas , Inibidores da Transcriptase Reversa/efeitos adversos , Células Cultivadas , Hipersensibilidade a Drogas/etiologia , Hipersensibilidade a Drogas/genética , Hipersensibilidade a Drogas/imunologia , Hipersensibilidade a Drogas/fisiopatologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , Antígenos HLA-B/genética , Humanos , Interferon gama/biossíntese , Leucócitos Mononucleares/imunologiaRESUMO
OBJECTIVES: A potentially life-threatening hypersensitive reaction accompanies the use of HIV nucleoside analogue abacavir (ABC) in 4-8% of Caucasian individuals. HLA-B*5701 and Hsp70 493T alleles have been shown to predict susceptibility to this hypersensitivity. DESIGN AND METHODS: This study was undertaken to provide a mechanistic understanding of the highly significant genetic association of HLA Class I and Hsp70 alleles with ABC hypersensitivity. RESULTS: In this study an ABC-induced localization of intracellular HSP70 to endosomal vesicles of antigen-presenting cells was demonstrated. This ABC-stimulated redistribution of endogenous HSP70 was substantially higher in the genetically homogenous HLA-B*5701, Hsp70 493T ABC-hypersensitive individuals and ABC-naive individuals in comparison with the heterogeneous tolerant patients (P = 0.023). Increased expression of HSP70 was also detected in the hypersensitive group as measured by flow cytometry (P = 0.032). Blocking of HSP70 and HSP70 cell surface receptors CD14 and TLR2 abrogated ABC-stimulated HSP70 redistribution in sensitized individuals to basal levels (P < 0.004). In addition, the use of TcRalphabeta and HLA-B57/58 antibodies also ablated the expression of HSP70. Cells expressing the activation markers CD40 were increased after ABC stimulation in the hypersensitive patients (P = 0.006). ABC-stimulated interferon-gamma levels were higher in hypersensitive patients in comparison with ABC-tolerant individuals with a mean of 123.54 versus 0 pg/ml (P = 0.001). CONCLUSION: The present data indicates that ABC stimulates an innate immune response and activates antigen-presenting cells via the endogenous HSP70-mediated Toll-like receptor pathway in genetically susceptible individuals potentially initiating the immuno-pathological hypersensitive response.
Assuntos
Células Apresentadoras de Antígenos/imunologia , Didesoxinucleosídeos/imunologia , Hipersensibilidade a Drogas/imunologia , Inibidores da Transcriptase Reversa/imunologia , Antígenos CD40/análise , Antígenos CD40/imunologia , Células Cultivadas , Retículo Endoplasmático/genética , Retículo Endoplasmático/imunologia , Endossomos/genética , Endossomos/imunologia , Imunofluorescência/métodos , Soropositividade para HIV/tratamento farmacológico , Soropositividade para HIV/imunologia , Antígenos HLA-B/genética , Antígenos HLA-B/imunologia , Proteínas de Choque Térmico HSP70/análise , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/imunologia , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Imunofenotipagem/métodos , Interferon gama/análise , Interferon gama/imunologia , Microscopia Confocal/métodos , Monócitos/imunologia , Receptores de Superfície Celular/imunologiaRESUMO
BACKGROUND: Abacavir hypersensitivity reaction (ABC HSR) is a potentially life-threatening adverse reaction that affects approximately 8% of patients that initiate this antiretroviral drug. Independent groups have shown a strong predictive association between ABC HSR and HLA-B*5701, indicating that exclusion of HLA-B*5701 positive individuals from abacavir treatment would largely prevent ABC HSR. However, the limited availability and relatively high cost of human leukocyte antigen (HLA) typing represent barriers to the widespread implementation of this pharmacogenetic approach to abacavir prescribing. To facilitate routine screening, we have developed a rapid flow cytometry method for HLA-B57 phenotyping using commercially available B17 monoclonal antibodies. METHODS: Whole blood samples from 84 human immunodeficiency virus (HIV) patients were examined by standard flow cytometry methods, using a two-colour B17-specific immunofluorescence assay in the CD45 lymphocyte population. RESULTS: All eight HLA-B57 individuals examined tested positive, while HLA-B57/58 negative individuals (n=74) tested negative for this flow cytometry test. Two non-HLA-B57 individuals showed weak cross-reactivity. CONCLUSION: In our predominantly Caucasian population, B17/CD45 dual staining was sufficient to identify individuals carrying B17 cell surface antigens. This approach, utilizing flow cytometry methods that are widely available in HIV laboratories, therefore offers a sensitive, rapid and cost-effective screening assay prior to abacavir prescription. Following risk stratification with this assay, it would be anticipated that identification of HLA-B*5701 using molecular HLA typing methods would be required in <10% of the screened population.
Assuntos
Fármacos Anti-HIV/efeitos adversos , Didesoxinucleosídeos/efeitos adversos , Hipersensibilidade a Drogas/prevenção & controle , Testes Genéticos , Teste de Histocompatibilidade/métodos , Alelos , Fármacos Anti-HIV/uso terapêutico , Didesoxinucleosídeos/uso terapêutico , Hipersensibilidade a Drogas/genética , Citometria de Fluxo , Soropositividade para HIV , Antígenos HLA-B/genética , Humanos , Sensibilidade e EspecificidadeRESUMO
There is a growing discussion surrounding the issue of personalized approaches to drug prescription based on an individual's genetic makeup. This field of investigation has focused primarily on identifying genetic factors that influence drug metabolism and cellular disposition, thereby contributing to dose-dependent toxicities and/or variable drug efficacy. However, pharmacogenetic approaches have also proved valuable in predicting drug hypersensitivity reactions in selected patient populations, including HIV-infected patients receiving long-term antiretroviral therapy. In this instance, susceptibility has been strongly linked to genetic loci involved in antigen recognition and presentation to the immune system--most notably within the major histocompatibility complex (MHC) region--consistent with the notion that hypersensitivity reactions represent drug-specific immune responses that are largely dose independent. Here the authors describe their experiences with the development of pharmacogenetic approaches to hypersensitivity reactions associated with abacavir and nevirapine, two commonly prescribed antiretroviral drugs. It is demonstrated that prospective screening tests to identify and exclude individuals with a certain genetic makeup may be largely successful in decreasing or eliminating incidence of these adverse drug reactions in certain populations. This review also explores the broader implications of these findings.
Assuntos
Fármacos Anti-HIV/efeitos adversos , Didesoxinucleosídeos/efeitos adversos , Hipersensibilidade a Drogas/fisiopatologia , Nevirapina/efeitos adversos , Animais , Biomarcadores , Hipersensibilidade a Drogas/genética , HIV-1/genética , HIV-1/imunologia , HumanosRESUMO
A patch test (PT) may be useful in defining true abacavir hypersensitivity syndrome (AHS). Seven previously PT-positive patients remote from the original AHS were shown to have robust 24 h responses, supporting PT durability. HLA-B*5701 was present in all seven PT-positive versus one of 11 controls tolerating abacavir (P < 0.001). Five of seven PT (71%) versus one of 11 controls (9%) (P = 0.005) showed significant abacavir-specific CD8 proliferation, suggesting a direct role for HLA-B*5701-restricted CD8 cells in the pathophysiology of AHS.
Assuntos
Fármacos Anti-HIV/efeitos adversos , Didesoxinucleosídeos/efeitos adversos , Toxidermias/etiologia , Inibidores da Transcriptase Reversa/efeitos adversos , Linfócitos T CD8-Positivos/imunologia , Toxidermias/diagnóstico , Toxidermias/imunologia , Predisposição Genética para Doença , Antígenos HLA-B/análise , Humanos , Testes do Emplastro/métodosRESUMO
Genetic (human leukocyte antigen), disease-related and demographic risk factors for nevirapine reactions were examined in a nevirapine-exposed cohort. Cases involving combinations of hepatitis, fever or rash were associated with an interaction between HLA-DRB1*0101 and the percentage of CD4, whereas no associations were detected for isolated rash. These data suggest that HLA-DRB1*0101 and the CD4 status may determine susceptibility to nevirapine hypersensitivity, consistent with a CD4 T-cell-dependent immune response to nevirapine-specific antigens.
Assuntos
Hipersensibilidade a Drogas/genética , Predisposição Genética para Doença/genética , Antígenos HLA-A/genética , Nevirapina/efeitos adversos , Inibidores da Transcriptase Reversa/efeitos adversos , Adulto , Estudos de Coortes , Hipersensibilidade a Drogas/imunologia , Feminino , Antígenos HLA/genética , Antígenos HLA/imunologia , Antígenos HLA-A/imunologia , Cadeias HLA-DRB1 , Humanos , Imunidade Celular/genética , Imunidade Celular/imunologia , MasculinoRESUMO
The application of a pharmacogenetic approach to antiretroviral drug therapy represents a significant challenge, as treatment involves multiple drugs and drug classes with the potential for significant variability in drug-host, as well as drug-drug, interactions. However, despite this inherent complexity, considerable gains have been made in understanding how genetic factors influence the efficacy and toxicity of HIV therapy. In this review the available evidence regarding genetic variation in drug disposition will be examined, including the potential for relatively polymorphic drug-metabolizing enzymes (e.g., cytochrome P450 isoforms) and drug transporters (e.g., P-glycoprotein) to influence the disposition of HIV protease inhibitor and non-nucleoside reverse transcriptase inhibitor drugs. In addition, the role of genetic variation in determining the immune response to drug-specific antigens will be considered as a potentially significant determinant of susceptibility to idiosyncratic drug reactions (e.g., major histocompatibility complex alleles associated with abacavir hypersensitivity). The current and potential clinical utility of pharmacogenetic testing in HIV management will also be emphasized.
Assuntos
Antirretrovirais/uso terapêutico , Infecções por HIV/genética , Farmacogenética , Antirretrovirais/efeitos adversos , Antirretrovirais/farmacologia , Transporte Biológico/genética , Hipersensibilidade a Drogas/etiologia , Hipersensibilidade a Drogas/genética , Variação Genética , Infecções por HIV/tratamento farmacológico , Síndrome de Lipodistrofia Associada ao HIV/induzido quimicamente , Síndrome de Lipodistrofia Associada ao HIV/genética , Humanos , Distribuição TecidualRESUMO
Members of the killer immunoglobulin (Ig)-like receptor (KIR) gene family are tightly clustered on human chromosome 19q13.4. Despite considerable variation in KIR gene content and allelic polymorphism, most KIR haplotypes belong to one of two broad groups termed A and B. The availability of contiguous genomic sequences for these haplotypes has allowed us to compare their genomic organization, nucleotide (nt) diversity and reconstruct their evolutionary history. The haplotypes have a framework of three conserved blocks containing (i) KIR3DL3, (ii) KIR3DP1, 2DL4, and (iii) KIR3DL2 that are interrupted by two variable segments that differ in the number and type of KIR genes. Low (0.05%) nucleotide diversity was detected across the centromeric and telomeric boundaries of the KIR gene cluster while higher SNP density (0.2%) occurred within the central region containing the KIR2DL4 gene. Phylogenetic and genomic analyses have permitted the reconstruction of a hypothetical ancestral haplotype that has revealed common groupings and differences between the KIR genes of the two haplotypes. The present phylogenetic and genomic comparison of the two sequenced KIR haplotypes provides a framework for a more thorough examination of KIR haplotype variations, diversity and evolution in human populations and between humans and non-human primates.
Assuntos
Evolução Molecular , Genoma , Haplótipos/genética , Receptores Imunológicos/genética , Animais , Ordem dos Genes , Variação Genética , Humanos , Modelos Genéticos , Filogenia , Polimorfismo de Nucleotídeo Único , Receptores KIR , Receptores KIR2DL4 , Receptores KIR3DL2RESUMO
Susceptibility to a clinically significant drug hypersensitivity syndrome associated with abacavir use seems to have a strong genetic component. We have previously shown that the presence of HLA-B*5701 strongly predicts abacavir hypersensitivity and have identified a potential susceptibility locus within a 300-kb region between the MEGT1 and C4A6 loci in the central MHC. We now report the results of fine recombinant genetic mapping in an expanded patient population of 248 consecutive, fully ascertained, abacavir-exposed individuals in the Western Australian HIV Cohort Study, in which 18 cases of definite abacavir hypersensitivity (7.3%) and 230 tolerant controls were identified. Haplotype mapping within patients with allelic markers of the 57.1 ancestral haplotype suggests a susceptibility locus within the 14-kb Hsp70 gene cluster. HLA-B*5701 was present in 94.4% of hypersensitive cases compared with 1.7% of controls (odds ratio, 960; P < 0.00001). A haplotypic nonsynonymous polymorphism of Hsp70-Hom (HspA1L, resulting from the substitution of residue M493T in the peptide-binding subunit) was found in combination with HLA-B*5701 in 94.4% of hypersensitive cases and 0.4% of controls (odds ratio, 3,893; P < 0.00001). Individuals with abacavir hypersensitivity demonstrated increased monocyte tumor necrosis factor expression in response to ex vivo abacavir stimulation, which was abrogated with CD8(+) T cell depletion. These data indicate that the concurrence of HLA-B*5701 and Hsp70-Hom M493T alleles is necessary for the development of abacavir hypersensitivity, which is likely to be mediated by an HLA-B*5701-restricted immune response to abacavir.
Assuntos
Didesoxinucleosídeos/imunologia , Hipersensibilidade a Drogas/imunologia , Antígenos HLA-B/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Mapeamento Cromossômico , Hipersensibilidade a Drogas/epidemiologia , Hipersensibilidade a Drogas/genética , Marcadores Genéticos , Antígenos HLA-B/genética , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/imunologia , Haplótipos/imunologia , Humanos , Complexo Principal de Histocompatibilidade/genética , Dados de Sequência Molecular , Prevalência , Linfócitos T/imunologia , Linfócitos T/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
OBJECTIVES: To examine the in vivo effects of highly active antiretroviral therapy (HAART) regimens on adipose tissue mitochondrial DNA (mtDNA) depletion, mitochondrial organellar proliferation, and markers of adipocyte differentiation and phenotype. DESIGN AND METHODS: DNA and mRNA quantification using real-time PCR methods was performed on adipose tissue samples from 31 HIV-infected individuals, of whom 11 were treatment-naive and 20 were receiving HAART. mtDNA depletion was measured as mtDNA copies/cell, and mitochondrial proliferation by quantification of mitochondrial protein mass. Regulation of mitochondrial biogenesis was assessed by NRF-1 and mtTFA mRNA. PPARgamma, UCP2 and UCP1 mRNA expression was used to assess adipocyte differentiation and phenotype. RESULTS: Stavudine-based HAART recipients (n=10) displayed significant mtDNA depletion (12.8% of control, P<0.001), mildly increased mitochondrial protein mass (2.6-fold of control, P=0.032) and decreased expression of PPARgamma (53.9% of control, P=0.021), UCP2 (62.2% of control, P=0.024) and UCP3 (51.8% of control, P=0.047) mRNA compared with controls. Zidovudine-based HAART recipients (n=7) also displayed significant mtDNA depletion (34.45% of control, P=0.031), increased mitochondrial protein mass (5.7-fold of control, P=0.009), and markedly increased UCP1 (18-fold of control, P=0.009) mRNA. Elevated UCP1 mRNA expression was found to be associated with non-stavudine (zidovudine or abacavir), protease inhibitor (PI)-containing HAART (95-fold of non-stavudine, non-PI-containing HAART, P=0.006). CONCLUSION: Differential effects of stavudine and zidovudine therapy on mtDNA depletion and expression of adipocyte differentiation markers PPARgamma and UCP2 were observed, consistent with increased adipose tissue toxicity associated with stavudine therapy. Increased UCP1 mRNA, a marker of brown adipose tissue phenotype, was associated with non-stavudine, PI-containing HAART, and may represent an adaptive response to the increased fatty acid flux associated with PI therapy, and may contribute to the increased resting energy expenditure reported in such patients.
Assuntos
Adipócitos/citologia , Tecido Adiposo/patologia , Terapia Antirretroviral de Alta Atividade/efeitos adversos , DNA Mitocondrial/metabolismo , Infecções por HIV/tratamento farmacológico , Mitocôndrias/fisiologia , Tecido Adiposo/metabolismo , Adulto , Fármacos Anti-HIV/efeitos adversos , Diferenciação Celular , DNA Mitocondrial/genética , Didesoxinucleosídeos/efeitos adversos , Inibidores da Protease de HIV/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Mitocôndrias/patologia , Proteínas Mitocondriais/metabolismo , Reação em Cadeia da Polimerase , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Inibidores da Transcriptase Reversa/efeitos adversos , Estavudina/efeitos adversos , Zidovudina/efeitos adversosRESUMO
BACKGROUND: Nucleoside analogue reverse transcriptase inhibitor (NRTI) therapy provides sufficient conditions for progressive subcutaneous fat wasting in HIV-infected patients. As NRTI-induced host toxicity is proposed to involve cellular mitochondrial DNA (mtDNA) depletion, determinants of cellular mtDNA copy number and mitochondrial mass in adipocyte samples from NRTI-treated HIV-infected patients and antiretroviral-naive controls were investigated. Adipose tissue morphology was also assessed. METHODS: Subcutaneous fat samples were obtained from NRTI-treated, HIV-infected patients (n = 21), antiretroviral therapy-naive HIV-infected controls (n = 11), and HIV-seronegative controls (n = 6). Non-adipocytes were removed by collagenase digestion. Adipocyte mtDNA copies/cell was measured using a real time PCR-based assay, and adipocyte mitochondrial protein content was also measured. Light and electron microscopy were performed on tissue samples. FINDINGS: Adipocyte mtDNA copies/cell values were similar (P = 0.56) in HIV seronegative and HIV-infected control groups. NRTI treatment was associated with reduced adipocyte mtDNA copies/cell, representing mean mtDNA depletion in NRTI-treated individuals of 77.7% compared with the mean value for the HIV-infected control group (P < 0001). Additionally, significant differences were found in adipocyte mtDNA copies/cell between patients receiving stavudine (n = 12, mean mtDNA depletion 87.1%) and zidovudine (n = 9, mean mtDNA depletion 52.1%) (P < 0.001). Adipocyte mitochondrial mass was increased in the stavudine group only (mean increase 289%, P < 0.01). INTERPRETATION: NRTI therapy is associated with mtDNA depletion and mitochondrial proliferation in adipocytes, consistent with the hypothesis that NRTI-induced mtDNA depletion contributes to the pathogenesis of subcutaneous fat wasting. Morphologic assessment also supports a role for NRTI therapy in inducing adipocyte metabolic dysfunction and cell death.
Assuntos
Adipócitos/ultraestrutura , DNA Mitocondrial/efeitos dos fármacos , Síndrome de Lipodistrofia Associada ao HIV/induzido quimicamente , Inibidores da Transcriptase Reversa/uso terapêutico , Análise de Variância , Terapia Antirretroviral de Alta Atividade , Estudos de Casos e Controles , Morte Celular , Estudos Transversais , DNA Mitocondrial/ultraestrutura , Infecções por HIV/tratamento farmacológico , Infecções por HIV/patologia , Síndrome de Lipodistrofia Associada ao HIV/patologia , Humanos , Microscopia Eletrônica , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Nucleoside reverse-transcriptase inhibitor (NRTI) therapy for human immunodeficiency virus (HIV) infection has been associated with mitochondrial DNA (mtDNA) polymerase-gamma inhibition and subsequent mtDNA depletion. Effects on mtDNA mutation, although suggested by critical involvement of polymerase-gamma in DNA-repair reactions, are unknown. In the present study, we assessed the nature and frequency of mitochondrial genome sequence differences in peripheral-blood samples taken prior to NRTI therapy and after 6-77 mo of treatment in 16 NRTI-treated patients. Samples from 10 HIV-infected, treatment-naive control individuals were taken at similar time intervals. Single-stranded conformation polymorphism (SSCP) and DNA-sequencing analysis techniques were used to detect mitochondrial genome sequence variants between paired longitudinal samples, and heteroplasmic populations were quantified after cloning and repeat SSCP/sequencing. Of 16 individuals treated with NRTIs, 5 exhibited altered SSCP profiles associated with the development of novel heteroplasmic DNA sequence changes, whereas no SSCP pattern change within these regions was observed in the control individuals. Heteroplasmic sequence changes were distributed across four regions of the genome: the noncoding region to 12S ribosomal RNA, reduced-nicotinamide-adenine-dinucleotide dehydrogenase 1, and cytochrome oxidase subunits I and III. Of the total of 26 patients who were examined in the present study, 4 of 5 patients with detectable mtDNA sequence changes since commencement of therapy developed evidence of peripheral fat wasting (lipoatrophy) between sample intervals (P=.031). One patient, without detectable sequence changes on NRTI therapy, also developed lipoatrophy. Levels of mtDNA copies/cell in blood samples were determined by quantitative PCR for 11 of the 16 NRTI-exposed patients; 7 of these 11 patients showed reduced levels of mtDNA in blood after therapy, including all 3 patients tested with evidence of mtDNA sequence changes on therapy. These data indicate that NRTI therapy provides conditions permissive for the development of peripheral-blood mtDNA mutations in vivo.
Assuntos
DNA Mitocondrial/genética , DNA Polimerase Dirigida por DNA/genética , Infecções por HIV/tratamento farmacológico , Infecções por HIV/genética , Mutagênese , Inibidores da Transcriptase Reversa/efeitos adversos , Sequência de Bases , Análise Mutacional de DNA , DNA Polimerase gama , Primers do DNA , DNA Mitocondrial/efeitos dos fármacos , DNA Ribossômico/genética , Humanos , Lamivudina/uso terapêutico , Dados de Sequência Molecular , Inibidores da Síntese de Ácido Nucleico , Polimorfismo Conformacional de Fita Simples , RNA Ribossômico/genética , Estavudina/uso terapêutico , Fatores de TempoRESUMO
Here, we compare the architecture of membrane receptors with extracellular Ig-like domains located within the leukocyte Ig-like receptor complex (LRC) of humans and mice. The receptors can be classified broadly into four groups, based on the homology of their Ig-like domains and gene architecture. Receptors in the first group are characterized by the presence of the Ig constant type 2-1 (IgC2-1) and variant Ig (vlg) domains, and include the leukocyte Ig-like receptors (LILRs) and murine paired Ig-activating receptors (PIRs). The second group of receptors possess an IgC2-2 domain and comprise the killer-cell Ig-like receptors (KIRs) and platelet collagen receptor glycoprotein VI (GPVI). The third group consists of receptors with IgC2-1, and IgC2-3 or IgC2-4 domains, and includes the receptor for IgA Fc (FCAR), NKp46 and murine Ly94. The fourth group, with a single extracellular IgC2-1 domain, consists of the leukocyte-associated Ig-like receptors (LAIRs). The genomic organization of and evolutionary associations between these receptors and their domains are examined.
Assuntos
Leucócitos/imunologia , Receptores Imunológicos/genética , Animais , Evolução Molecular , Humanos , Camundongos , Receptores Imunológicos/classificaçãoRESUMO
A survey of KIR2DL4 polymorphism revealed seven common sequences in the Australian population. The seven sequences encode three different amino acid sequences of the immunoglobulin domains. Two of the sequences encoding different amino acid sequences in the immunoglobulin domains also occur on some chromosomes with a single nucleotide deletion at the end of exon 6, which encodes the transmembrane domain (DeltaTM mutation), resulting in exon 6 skipping during mRNA production. Due to alternate splicing, a fraction of the mRNA produced by these alleles includes the transmembrane region but is missing the cytoplasmic region. The remaining two sequences differed only by synonymous substitutions. All of the exonic polymorphisms of KIR2DL4 could be detected by single-stranded conformational polymorphism of individually amplified exons. The DeltaTM mutation is in linkage disequilibrium with the killer cell immunoglobulin-like receptor (KIR) A haplotype, and the wild-type sequence is in linkage disequilibrium with the B haplotype. The frequencies of alleles with the DeltaTM mutation or Ig-domain polymorphisms did not differ between women who experienced pre-eclampsia and normotensive controls. Similarly there was no difference in the KIR gene repertoire in pre-eclampsia and normotensive controls.