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Clustered regularly interspersed short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) technology has revolutionized the field of gene therapy as it has enabled precise genome editing with unprecedented accuracy and efficiency, paving the way for clinical applications to treat otherwise incurable genetic disorders. Typically, precise genome editing requires the delivery of multiple components to the target cells that, depending on the editing platform used, may include messenger RNA (mRNA), protein complexes, and DNA fragments. For clinical purposes, these have to be efficiently delivered into transplantable cells, such as primary T lymphocytes or hematopoietic stem and progenitor cells that are typically sensitive to exogenous substances. This challenge has limited the broad applicability of precise gene therapy applications to those strategies for which efficient delivery methods are available. Electroporation-based methodologies have been generally applied for gene editing applications, but procedure-associated toxicity has represented a major burden. With the advent of novel and less disruptive methodologies to deliver genetic cargo to transplantable cells, it is now possible to safely and efficiently deliver multiple components for precise genome editing, thus expanding the applicability of these strategies. In this review, we describe the different delivery systems available for genome editing components, including viral and non-viral systems, highlighting their advantages, limitations, and recent clinical applications. Recent improvements to these delivery methods to achieve cell specificity represent a critical development that may enable in vivo targeting in the future and will certainly play a pivotal role in the gene therapy field.
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Sistemas CRISPR-Cas , Edição de Genes , Técnicas de Transferência de Genes , Terapia Genética , Humanos , Edição de Genes/métodos , Terapia Genética/métodos , Animais , Vetores Genéticos/genética , Vírus/genéticaRESUMO
Background: We conducted a phase III, non-inferiority trial comparing safety and efficacy of RCP recombinant spike protein Covid-19 vaccine to BBIBP (Sinopharm). Methods: Adult Iranian population received RCP or BBIBP in a randomized, double blind and an additional non-randomized open labeled trial arms. Eligible participants signed a written informed consent and received two intramuscular injections three weeks apart. In the randomized arm, an intranasal dose of vaccine or adjuvant-only preparation were given to the RCP and BBIBP recipients at day 51 respectively. Participants were actively followed for up to 4 months for safety and efficacy outcomes. Primary outcome was PCR + symptomatic Covid-19 disease two weeks after the second dose. The non-inferiority margin was 10% of reported BBIBP vaccine efficacy (HR = 1.36). Results: We recruited 23,110 participants (7224 in the randomized and 15,886 in the non-randomized arm). We observed 604 primary outcome events during 4 months of active follow-up including 121 and 133 in the randomized and 157 and 193 cases in the non-randomized arms among recipients of RCP and BBIBP respectively. Adjusted hazard ratios for the primary outcome in those receiving RCP compared with BBIBP interval were 0.91 (0.71-1.16) and 0.62 (0.49-0.77) in the randomized and non-randomized arms respectively. The upper boundary of 99.1% confidence interval of HR = 0.91 (0.67-1.22) remained below the margin of non-inferiority in the randomized arm after observing the early stopping rules using O'Brien Fleming method. Conclusion: Our study showed that the RCP efficacy is non-inferior and its safety profile is comparable to the BBIBP.
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BACKGROUND: The immunity induced by primary vaccination is effective against COVID-19; however, booster vaccines are needed to maintain vaccine-induced immunity and improve protection against emerging variants. Heterologous boosting is believed to result in more robust immune responses. This study investigated the safety and immunogenicity of the Razi Cov Pars vaccine (RCP) as a heterologous booster dose in people primed with Beijing Bio-Institute of Biological Products Coronavirus Vaccine (BBIBP-CorV). METHODS: We conducted a randomized, double-blind, active-controlled trial in adults aged 18 and over primarily vaccinated with BBIBP-CorV, an inactivated SARS-CoV-2 vaccine. Eligible participants were randomly assigned (1:1) to receive a booster dose of RCP or BBIBP-CorV vaccines. The primary outcome was neutralizing antibody activity measured by a conventional virus neutralization test (cVNT). The secondary efficacy outcomes included specific IgG antibodies against SARS-CoV-2 spike (S1 and receptor-binding domain, RBD) antigens and cell-mediated immunity. We measured humoral antibody responses at 2 weeks (in all participants) and 3 and 6 months (a subgroup of 101 participants) after the booster dose injection. The secondary safety outcomes were solicited and unsolicited immediate, local, and systemic adverse reactions. RESULTS: We recruited 483 eligible participants between December 7, 2021, and January 13, 2022. The mean age was 51.9 years, and 68.1% were men. Neutralizing antibody titers increased about 3 (geometric mean fold increase, GMFI = 2.77, 95% CI 2.26-3.39) and 21 (GMFI = 21.51, 95% CI 16.35-28.32) times compared to the baseline in the BBIBP-CorV and the RCP vaccine groups. Geometric mean ratios (GMR) and 95% CI for serum neutralizing antibody titers for RCP compared with BBIBP-CorV on days 14, 90, and 180 were 6.81 (5.32-8.72), 1.77 (1.15-2.72), and 2.37 (1.62-3.47) respectively. We observed a similar pattern for specific antibody responses against S1 and RBD. We detected a rise in gamma interferon (IFN-γ), tumor necrosis factor (TNF-α), and interleukin 2 (IL-2) following stimulation with S antigen, particularly in the RCP group, and the flow cytometry examination showed an increase in the percentage of CD3 + /CD8 + lymphocytes. RCP and BBIBP-CorV had similar safety profiles; we identified no vaccine-related or unrelated deaths. CONCLUSIONS: BBIBP-CorV and RCP vaccines as booster doses are safe and provide a strong immune response that is more robust when the RCP vaccine is used. Heterologous vaccines are preferred as booster doses. TRIAL REGISTRATION: This study was registered with the Iranian Registry of Clinical Trial at www.irct.ir , IRCT20201214049709N4. Registered 29 November 2021.
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Vacinas contra COVID-19 , Glicoproteína da Espícula de Coronavírus , Vacinas de Produtos Inativados , Adulto , Masculino , Humanos , Adolescente , Pessoa de Meia-Idade , Feminino , Vacinas contra COVID-19/efeitos adversos , Irã (Geográfico) , Anticorpos Neutralizantes , Anticorpos AntiviraisRESUMO
BACKGROUND: This study explores the safety and immunogenicity of the Razi-Cov-Pars (RCP) SARS Cov-2 recombinant spike protein vaccine. METHOD: In a randomized, double-blind, placebo-controlled trial, adults aged 18-70 were randomly allocated to receive selected 10 µg/200 µl vaccine strengths or placebo (adjuvant). It included two intramuscular injections at days 0 and 21, followed by an intranasal dose at day 51. Immediate and delayed solicited local and systemic adverse reactions after each dose up to a week, and specific IgG antibodies against SARS Cov-2 spike antigens two weeks after the 2nd dose were assessed as primary outcomes. Secondary safety outcomes were abnormal laboratory findings and medically attended adverse events (MAAE) over six months follow up. Secondary immunogenicity outcomes were neutralizing antibody activity and cell-mediated immune response. RESULT: Between May 27th and July 15th, 2021, 500 participants were enrolled. Participants' mean (SD) age was 37.8 (9.0), and 67.0 % were male. No immediate adverse reaction was observed following the intervention. All solicited local and systemic adverse events were moderate (Grade I-II). Specific IgG antibody response against S antigen in the vaccine group was 5.28 times (95 %CI: 4.02-6.94) the placebo group with a 75 % seroconversion rate. During six months of follow-up, 8 SAEs were reported, unrelated to the study intervention. The participants sustained their acquired humoral responses at the end of the sixth month. The vaccine predominantly resulted in T-helper 1 cell-mediated immunity, CD8+ cytotoxic T-cell increase, and no increase in inflammatory IL-6 cytokine. CONCLUSION: RCP vaccine is safe and creates strong and durable humoral and cellular immunity. TRIAL REGISTRATION: (IRCT20201214049709N2).
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COVID-19 , Síndrome Respiratória Aguda Grave , Vacinas , Adulto , Humanos , Masculino , Feminino , Vacinas contra COVID-19/efeitos adversos , COVID-19/prevenção & controle , Anticorpos Neutralizantes , Imunoglobulina G , Método Duplo-Cego , Imunogenicidade da Vacina , Anticorpos AntiviraisRESUMO
Objectives: This study aimed to determine the safety and immunogenicity of a combined intramuscular/intranasal recombinant spike protein COVID-19 vaccine (RCP). Methods: We conducted a randomized, double-blind, placebo-controlled, phase I trial. Three vaccine strengths were compared with an adjuvant-only preparation. It included two intramuscular and a third intranasal dose. Eligible participants were followed for adverse reactions. Specific IgG, secretory IgA, neutralizing antibodies, and cell-mediated immunity were assessed. Results: A total of 153 participants were enrolled (13 sentinels, 120 randomized, 20 non-randomized open-labeled for IgA assessment). No related serious adverse event was observed. The geometric mean ratios (GMRs) and 95% CI for serum neutralizing antibodies compared with placebo two weeks after the second injection were 5.82 (1.46-23.13), 11.12 (2.74-45.09), and 20.70 (5.05-84.76) in 5, 10, and 20 µg vaccine groups, respectively. The GMR for anti-RBD IgA in mucosal fluid two weeks after the intranasal dose was 23.27 (21.27-25.45) in the 10 µg vaccine group. The humoral responses were sustained for up to five months. All vaccine strengths indicated a strong T-helper 1 response. Conclusion: RCP is safe and creates strong and durable humoral and cellular immunity and good mucosal immune response in its 10 µg /200 µL vaccine strengths. Trial registration: IRCT20201214049709N1.
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Several vaccine candidates for COVID-19 have been developed, and few vaccines received emergency approval with an acceptable level of efficacy and safety. We herein report the development of the first recombinant protein-based vaccine in Iran based on the recombinant SARS-CoV-2 spike protein in its monomeric (encompassing amino acid 1-674 for S1 and 685-1211 for S2 subunits) and trimer form (S-Trimer) formulated in the oil-in-water adjuvant system RAS-01 (Razi Adjuvant System-01). The safety and immunity of the candidate vaccine, referred to as RAZI-COV PARS, were evaluated in Syrian hamster, BALB/c mice, Pirbright guinea pig, and New Zeeland white (NZW) rabbit. All vaccinated animals received two intramuscular (IM) and one intranasal (IN) candidate vaccine at 3-week intervals (days 0, 21, and 51). The challenge study was performed intranasally with 5×106 pfu of SARS-CoV-2 35 days post-vaccination. None of the vaccinated mice, hamsters, guinea pigs, or rabbits showed any changes in general clinical observations; body weight and food intake, clinical indicators, hematology examination, blood chemistry, and pathological examination of vital organs. Safety of vaccine after the administration of single and repeated dose was also established. Three different doses of candidate vaccine stimulated remarkable titers of neutralizing antibodies, S1, Receptor-Binding Domain (RBD), and N-terminal domain (NTD) specific IgG antibodies as well as IgA antibodies compared to placebo and control groups (P<0.01). Middle and high doses of RAZI-COV PARS vaccine significantly induced a robust and quick immune response from the third-week post-immunization. Histopathological studies on vaccinated hamsters showed that the challenge with SARS-CoV-2 did not induce any modifications in the lungs. The protection of the hamster was documented by the absence of lung pathology, the decreased virus load in the lung, rapid clearance of the virus from the lung, and strong humoral and cellular immune response. These findings confirm the immunogenicity and efficacy of the RAZI-COV PARS vaccine. Of the three tested vaccine regimens, the middle dose of the vaccine showed the best protective immune parameters. This vaccine with heterologous prime-boost vaccination method can be a good candidate to control the viral infection and its spread by stimulating central and mucosal immunity.
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Vacinas contra COVID-19 , COVID-19 , Animais , Anticorpos Antivirais , COVID-19/prevenção & controle , Vacinas contra COVID-19/efeitos adversos , Cricetinae , Cobaias , Humanos , Camundongos , Modelos Animais , Coelhos , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Vacinas Combinadas , Vacinas SintéticasRESUMO
Background: Junctional epidermolysis bullosa (JEB) is an autosomal recessive skin disorder with defective adhesion of dermal- epidermal within the lamina lucida region of the basement membrane zone. The main characterization of JEB is blistering and fragile skin and mucous membrane. Laminins are noncollagenous part of basement membrane and classified as a family of extracellular matrix glycoprotein. Laminins contain three chains: Laminin α, Laminin ß and Laminin γ. LAMC2 (laminin subunit gamma 2) gene encodes γ subunit of laminin and its mutation contributes to JEB. Here, we report a disease-causing nonsense mutation and a large deletion mutation in LAMC2 gene in two families affected by JEB. Methods: Whole exome sequencing (WES) was carried out on the mother of patient in family I and the patient himself in family II to detect the underlying mutations. Then, sanger sequencing was performed to confirm the identified mutations. Results: Next generation sequencing (NGS) data analysis of the first family showed a novel, nonsense mutation in LAMC2 gene (LAMC2: NM_005562: exon14:c.C2143T: p.R715X). The heterozygous state of the mutation was confirmed by sanger sequencing in the parents and unaffected brother. In Family II, NGS data had no coverage in the large area of LAMC2 gene. Thus, to confirm the possible deletion sanger sequencing was done and blasting of sequence showed the deleted region of 9.4 kb (exon10-17) in LAMC2 gene. Conclusion: In summary, current study reported a novel disease-causing premature termination codon (PTC) mutation in LAMC2 gene and a large deletion mutation in patients affected by JEB.
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Dystroglycan (DG) is a major cell membrane glycoprotein, which is encoded by the DAG1 gene. α-DG is one of DG subunits, belongs to O-mannosylated protein of mammals and was identified in brain, peripheral nerves and muscle. Dystroglycanopathies are a group of heterogeneous congenital muscular dystrophies, which can result from defective α-DG mannosylation. First line of α-DG glycosylation is catalyzed by protein O-mannosyltransferase family (PMT). In this study, the mutation was identified in the POMT2 gene, which encodes O-mannosyltransferase 2 protein and its mutations can be contributed to dystroglycanopathies. A very rare missense mutation in the POMT2 gene (NM_013382: exon9: c. 1106G>A) was identified by next generation sequencing (NGS) and was subsequently confirmed using Sanger sequencing in both affected siblings. There was no report of this mutation in the literature, therefore, the significance was uncertain. Our findings confirmed the pathogenicity of mutation and expanded the mutation spectrum of POMT2, which will be helpful in further molecular evaluations of muscular diseases.
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Different mutations in glutamate receptor ionotropic delta 2 (GRID2) gene cause cerebellar ataxia in human. We report the largest homozygous deletion of the GRID2 gene reported to date, most probably causing complete loss of the gene product. Our patient presents mainly early onset cerebellar ataxia, cerebellar atrophy, nystagmus, and developmental delay with the least amount of intellectual disability.
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Autosomal recessive (AR) gene defects are the leading genetic cause of intellectual disability (ID) in countries with frequent parental consanguinity, which account for about 1/7th of the world population. Yet, compared to autosomal dominant de novo mutations, which are the predominant cause of ID in Western countries, the identification of AR-ID genes has lagged behind. Here, we report on whole exome and whole genome sequencing in 404 consanguineous predominantly Iranian families with two or more affected offspring. In 219 of these, we found likely causative variants, involving 77 known and 77 novel AR-ID (candidate) genes, 21 X-linked genes, as well as 9 genes previously implicated in diseases other than ID. This study, the largest of its kind published to date, illustrates that high-throughput DNA sequencing in consanguineous families is a superior strategy for elucidating the thousands of hitherto unknown gene defects underlying AR-ID, and it sheds light on their prevalence.
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Genes Recessivos/genética , Deficiência Intelectual/genética , Adulto , Consanguinidade , Exoma/genética , Família , Feminino , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Homozigoto , Humanos , Irã (Geográfico) , Masculino , Pessoa de Meia-Idade , Mutação/genética , Linhagem , Mapas de Interação de Proteínas/genética , Sequenciamento do Exoma/métodos , Sequenciamento Completo do Genoma/métodosRESUMO
Purpose: The aim of this study was to identify the molecular genetic basis of hereditary retinal dystrophies (HRDs) in five unrelated Iranian families. Methods: Whole exome sequencing and Sanger sequencing were performed in all families. Variants were analyzed using various bioinformatics databases and software. Results: Based on the selected strategies, we identified potentially causative variants in five families with HRDs: the novel homozygous deletion mutation c.586_589delTTTG (p.F196Sfs*56) in the TTC8 gene of family A, the novel homozygous missense mutation c.2389T>C (p.S797P) in the CRB1 gene in family B, the novel homozygous frameshift mutation c.2707dupA (p.S903Kfs*66) in the LRP5 gene in family C, the novel homozygous splice mutation c.584-1G>T in the MERTK gene in family D, and the novel homozygous missense mutation c.1819G>C (p.G607R) rs61749412 in the ABCA4 gene of family E. Conclusions: This study highlights the presence of five novel variants associated with retinal dystrophies in selected Iranian families with hereditary blindness.
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Sequenciamento do Exoma , Oftalmopatias Hereditárias/diagnóstico , Predisposição Genética para Doença , Distrofias Retinianas/diagnóstico , Transportadores de Cassetes de Ligação de ATP/genética , Adulto , Povo Asiático/genética , Criança , Proteínas do Citoesqueleto , Análise Mutacional de DNA , Oftalmopatias Hereditárias/genética , Proteínas do Olho/genética , Feminino , Humanos , Lactente , Irã (Geográfico) , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Masculino , Proteínas de Membrana/genética , Biologia Molecular , Proteínas do Tecido Nervoso/genética , Linhagem , Proteínas/genética , Distrofias Retinianas/genética , c-Mer Tirosina Quinase/genéticaRESUMO
Sjögren-Larsson syndrome (SLS) is a rare type of congenital ichthyosis with neurological problems and intellectual disability. Homozygous mutations in ALDH3A2 gene are known to be responsible for this syndrome. Here, we report an Iranian family with congenital SLS bearing a novel two-base-pair deletion within ALDH3A2 genomic sequence. Our finding expands the mutation spectrum of ALDH3A2 that is applicable for further molecular studies and management of SLS.
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Cockayne syndrome (CS) is a rare autosomal recessive multisystem disorder characterized by impaired neurological and sensory functions, cachectic dwarfism, microcephaly, and photosensitivity. This syndrome shows a variable age of onset and rate of progression, and its phenotypic spectrum include a wide range of severity. Due to the progressive nature of this disorder, diagnosis can be more important when additional signs and symptoms appear gradually and become steadily worse over time. Therefore, mutation analysis of genes involved in CS pathogenesis can be helpful to confirm the suspected clinical diagnosis. Here, we report a novel mutation in ERCC8 gene in a 16-year-old boy who suffers from poor weight gain, short stature, microcephaly, intellectual disability, and photosensitivity. The patient was born to consanguineous family with no previous documented disease in his parents. To identify disease-causing mutation in the patient, whole exome sequencing utilizing next-generation sequencing on an Illumina HiSeq 2000 platform was performed. Results revealed a novel homozygote mutation in ERCC8 gene (NM_000082: exon 11, c.1122G>C) in our patient. Another gene (ERCC6), which is also involved in CS did not have any disease-causing mutations in the proband. The new identified mutation was then confirmed by Sanger sequencing in the proband, his parents, and extended family members, confirming co-segregation with the disease. In addition, different bioinformatics programs which included MutationTaster, I-Mutant v2.0, NNSplice, Combined Annotation Dependent Depletion, The PhastCons, Genomic Evolutationary Rate Profiling conservation score, and T-Coffee Multiple Sequence Alignment predicted the pathogenicity of the mutation. Our study identified a rare novel mutation in ERCC8 gene and help to provide accurate genetic counseling and prenatal diagnosis to minimize new affected individuals in this family.
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BACKGROUND: Countries with culturally accepted consanguinity provide a unique resource for the study of rare recessively inherited genetic diseases. Although hereditary hearing loss (HHL) is not uncommon, it is genetically heterogeneous, with over 85 genes causally implicated in non-syndromic hearing loss (NSHL). This heterogeneity makes many gene-specific types of NSHL exceedingly rare. We sought to define the spectrum of autosomal recessive HHL in Iran by investigating both common and rarely diagnosed deafness-causing genes. DESIGN: Using a custom targeted genomic enrichment (TGE) panel, we simultaneously interrogated all known genetic causes of NSHL in a cohort of 302 GJB2-negative Iranian families. RESULTS: We established a genetic diagnosis for 67% of probands and their families, with over half of all diagnoses attributable to variants in five genes: SLC26A4, MYO15A, MYO7A, CDH23 and PCDH15. As a reflection of the power of consanguinity mapping, 26 genes were identified as causative for NSHL in the Iranian population for the first time. In total, 179 deafness-causing variants were identified in 40 genes in 201 probands, including 110 novel single nucleotide or small insertion-deletion variants and three novel CNV. Several variants represent founder mutations. CONCLUSION: This study attests to the power of TGE and massively parallel sequencing as a diagnostic tool for the evaluation of hearing loss in Iran, and expands on our understanding of the genetics of HHL in this country. Families negative for variants in the genes represented on this panel represent an excellent cohort for novel gene discovery.
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Perda Auditiva/genética , Conexina 26 , Conexinas , Consanguinidade , Efeito Fundador , Frequência do Gene , Genes Recessivos , Estudos de Associação Genética , Predisposição Genética para Doença , Perda Auditiva/patologia , Humanos , Irã (Geográfico)RESUMO
OBJECTIVE: Hereditary hearing loss is the most common neurosensory disorder in humans. Half of the cases have genetic etiology with extraordinary genetic heterogeneity. Mutations in one gene, GJB2, are the most common cause for autosomal recessive non-syndromic hearing loss (ARNSHL) in many different populations. GJB2 encodes a gap junction channel protein (connexin 26), and is located on DFNB1 locus on chromosome 13q12.11 which also involve another connexin gene, GJB6. Mutation screening of GJB2 revealed that a high number of patients with deaf phenotype have heterozygous genotype and carry only one mutant allele. As the first comprehensive study in Iran, we have targeted GJB2-related Iranian heterozygotes, looking for second mutant allele which leads to hearing impairment. They bear first mutation in their coding exon of GJB2. METHOD: Using PCR-based direct sequencing, we assessed 103 patients with ARNSHL for variants in non-coding exon and promoter region of this gene, for the first time in Iran. RESULT: We have identified the second mutant allele in splice site of exon-1 of GJB2 which is known as IVS1+1G>A in 17 probands. We found no mutation in promoter region of GJB2. CONCLUSION: Our findings reveal that IVS1+1G>A mutation in noncoding exon of GJB2 is the most common mutation after 35delG within multi ethnical Iranian heterozygote samples. It emphasizes to approach exon1 of GJB2 in case of ARNSHL genetic diagnosis.
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Conexinas/genética , Surdez/genética , Mutação , Alelos , Conexina 26 , Testes Genéticos , Heterozigoto , Humanos , Irã (Geográfico)/epidemiologia , Fenótipo , Reação em Cadeia da Polimerase , Análise de Sequência de DNARESUMO
BACKGROUND: Regulatory T cells (T-regs) have an important role in cancer by suppression of protective antitumor immune responses. Regulatory T cells express the forkhead/winged helix transcription factor (FOXP3) and OX40 molecules which have important regulatory roles in the immune system. OBJECTIVE: To evaluate FOXP3 and OX40 transcripts in the peripheral blood mononuclear cells of women with breast cancer. METHODS: Blood samples from 40 women with histologically-confirmed infiltrating ductal carcinoma of the breast and 40 healthy volunteer women without a history of malignancy or autoimmune disorders were collected. The abundance of FOXP3 and OX40 gene transcripts were determined by quantitative real-time PCR (qRT-PCR). RESULTS: There was a significant positive correlation between FOXP3 and OX40 gene expression in women with breast cancer in a stage dependent manner. CONCLUSION: This finding emphasizes the importance of T-regs as predominant targets for breast cancer immunotherapy.
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Neoplasias da Mama/imunologia , Carcinoma Ductal/imunologia , Fatores de Transcrição Forkhead/genética , Receptores OX40/genética , Linfócitos T Reguladores/imunologia , Transcrição Gênica , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/patologia , Carcinoma Ductal/patologia , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Pessoa de Meia-Idade , Estadiamento de NeoplasiasRESUMO
OBJECTIVE: Mutations in GJB2, encoding connexin 26 (CX26), are causally related to autosomal recessive form of non-syndromic hearing loss (NSHL) at the DFNB1 locus and autosomal dominant NSHL at the DFNA3 locus. In this study, we investigated the prevalence of GJB2 mutations in the Iranian deaf population. METHODS: A total of 2322 deaf probands presenting the ethnically diverse Iranian population were screened for variants in GJB2. All persons were first screened for the c.35delG mutation, as this variant is the most prevalent GJB2-deafness causing mutation in the Iranian population. In all persons carrying zero or one c.35delG allele, exons 1 and 2 were then sequenced. RESULTS: In total, 374 (~16%) families segregated GJB2-related deafness caused by 45 different mutations and 5 novel variants. The c.35delG mutation was most commonly identified and accounts for ~65% of the GJB2 mutations found in population studied. CONCLUSION: Our data also show that there is a gradual decrease in the frequency of the c.35delG mutation and of GJB2-related deafness in general in a cline across Iran extending from the northwest to southeast.
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Conexinas/genética , Perda Auditiva/genética , Mutação , Conexina 26 , Consanguinidade , Análise Mutacional de DNA , Perda Auditiva/epidemiologia , Humanos , Irã (Geográfico)/epidemiologia , Polimorfismo Genético , PrevalênciaRESUMO
Mutations in the SLC26A4 gene at the DFNB4 locus are responsible for Pendred syndrome and non-syndromic hereditary hearing loss (DFNB4). This study included 80 nuclear families with two or more siblings segregating presumed autosomal recessive hearing loss. All deaf persons tested negative for mutations in GJB2 at the DFNB1 locus and were, therefore, screened for autozygosity by descent (ABD) using short tandem repeat polymorphisms (STRPs) that flanked SLC26A4. In 12 families, homozygosity for STRPs suggested possible ABD in this genomic region. Affected individuals in five families had a positive perchlorate discharge test. Sequence analysis of SLC26A4 identified ten mutations in eight families (T420I, 1197delT, G334V, R409H, T721M, R79X, S448L, L597S, 965insA and L445W), of which, four are novel (T420I, G334V, 965insA and R79X). These results imply that Pendred syndrome is the most prevalent form of syndromic hereditary hearing loss in Iran.