RESUMEN

Mycobacterium tuberculosis remains the most common infectious killer worldwide despite decades of antitubercular drug development. Effectively controlling the tuberculosis (TB) pandemic will require innovation in drug discovery. In this review, we provide a brief overview of the two main approaches to discovering new TB drugs-phenotypic screens and target-based drug discovery-and outline some of the limitations of each method. We then explore recent advances in genetic tools that aim to overcome some of these limitations. In particular, we highlight a novel metric to prioritize essential targets, termed vulnerability. Stratifying targets based on their vulnerability presents new opportunities for future target-based drug discovery campaigns.

Asunto(s)

Antituberculosos , Descubrimiento de Drogas , Mycobacterium tuberculosis , Tuberculosis , Descubrimiento de Drogas/métodos , Descubrimiento de Drogas/tendencias , Humanos , Antituberculosos/farmacología , Antituberculosos/uso terapéutico , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis/tratamiento farmacológico , Terapia Molecular Dirigida/métodos , Terapia Molecular Dirigida/tendencias

RESUMEN

Drug-resistant bacteria are emerging as a global threat, despite frequently being less fit than their drug-susceptible ancestors1-8. Here we sought to define the mechanisms that drive or buffer the fitness cost of rifampicin resistance (RifR) in the bacterial pathogen Mycobacterium tuberculosis (Mtb). Rifampicin inhibits RNA polymerase (RNAP) and is a cornerstone of modern short-course tuberculosis therapy9,10. However, RifR Mtb accounts for one-quarter of all deaths due to drug-resistant bacteria11,12. We took a comparative functional genomics approach to define processes that are differentially vulnerable to CRISPR interference (CRISPRi) inhibition in RifR Mtb. Among other hits, we found that the universally conserved transcription factor NusG is crucial for the fitness of RifR Mtb. In contrast to its role in Escherichia coli, Mtb NusG has an essential RNAP pro-pausing function mediated by distinct contacts with RNAP and the DNA13. We find this pro-pausing NusG-RNAP interface to be under positive selection in clinical RifR Mtb isolates. Mutations in the NusG-RNAP interface reduce pro-pausing activity and increase fitness of RifR Mtb. Collectively, these results define excessive RNAP pausing as a molecular mechanism that drives the fitness cost of RifR in Mtb, identify a new mechanism of compensation to overcome this cost, suggest rational approaches to exacerbate the fitness cost, and, more broadly, could inform new therapeutic approaches to develop drug combinations to slow the evolution of RifR in Mtb.

Asunto(s)

Proteínas Bacterianas , Farmacorresistencia Bacteriana , Evolución Molecular , Aptitud Genética , Mycobacterium tuberculosis , Rifampin , Humanos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Secuencia Conservada , ARN Polimerasas Dirigidas por ADN/antagonistas & inhibidores , ARN Polimerasas Dirigidas por ADN/genética , ARN Polimerasas Dirigidas por ADN/metabolismo , Farmacorresistencia Bacteriana/efectos de los fármacos , Farmacorresistencia Bacteriana/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Genómica , Mutación , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/enzimología , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/metabolismo , Factores de Elongación de Péptidos/genética , Factores de Elongación de Péptidos/metabolismo , Rifampin/farmacología , Rifampin/uso terapéutico , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/microbiología

RESUMEN

Pathogenic mycobacteria are a significant cause of morbidity and mortality worldwide. The conserved whiB7 stress response reduces the effectiveness of antibiotic therapy by activating several intrinsic antibiotic resistance mechanisms. Despite our comprehensive biochemical understanding of WhiB7, the complex set of signals that induce whiB7 expression remain less clear. We employed a reporter-based, genome-wide CRISPRi epistasis screen to identify a diverse set of 150 mycobacterial genes whose inhibition results in constitutive whiB7 expression. We show that whiB7 expression is determined by the amino acid composition of the 5' regulatory uORF, thereby allowing whiB7 to sense amino acid starvation. Although deprivation of many amino acids can induce whiB7, whiB7 specifically coordinates an adaptive response to alanine starvation by engaging in a feedback loop with the alanine biosynthetic enzyme, aspC. These findings describe a metabolic function for whiB7 and help explain its evolutionary conservation across mycobacterial species occupying diverse ecological niches.

Asunto(s)

Mycobacterium tuberculosis , Mycobacterium , Factores de Transcripción/metabolismo , Alanina/genética , Alanina/metabolismo , Regulación Bacteriana de la Expresión Génica , Mycobacterium/genética , Mycobacterium/metabolismo , Farmacorresistencia Microbiana , Mycobacterium tuberculosis/metabolismo , Proteínas Bacterianas/metabolismo

RESUMEN

Pathogenic mycobacteria are a significant cause of morbidity and mortality worldwide. These bacteria are highly intrinsically drug resistant, making infections challenging to treat. The conserved whiB7 stress response is a key contributor to mycobacterial intrinsic drug resistance. Although we have a comprehensive structural and biochemical understanding of WhiB7, the complex set of signals that activate whiB7 expression remain less clear. It is believed that whiB7 expression is triggered by translational stalling in an upstream open reading frame (uORF) within the whiB7 5' leader, leading to antitermination and transcription into the downstream whiB7 ORF. To define the signals that activate whiB7, we employed a genome-wide CRISPRi epistasis screen and identified a diverse set of 150 mycobacterial genes whose inhibition results in constitutive whiB7 activation. Many of these genes encode amino acid biosynthetic enzymes, tRNAs, and tRNA synthetases, consistent with the proposed mechanism for whiB7 activation by translational stalling in the uORF. We show that the ability of the whiB7 5' regulatory region to sense amino acid starvation is determined by the coding sequence of the uORF. The uORF shows considerable sequence variation among different mycobacterial species, but it is universally and specifically enriched for alanine. Providing a potential rationalization for this enrichment, we find that while deprivation of many amino acids can activate whiB7 expression, whiB7 specifically coordinates an adaptive response to alanine starvation by engaging in a feedback loop with the alanine biosynthetic enzyme, aspC. Our results provide a holistic understanding of the biological pathways that influence whiB7 activation and reveal an extended role for the whiB7 pathway in mycobacterial physiology, beyond its canonical function in antibiotic resistance. These results have important implications for the design of combination drug treatments to avoid whiB7 activation, as well as help explain the conservation of this stress response across a wide range of pathogenic and environmental mycobacteria.

RESUMEN

Halogenated platinum salts are known respiratory sensitizers in the workplace, and occupational exposure to platinum via the respiratory system and skin has been reported. The aim of this study was to compare the permeability and skin retention of potassium hexachloroplatinate to previously published data of potassium tetrachloroplatinate. Experiments were performed using female Caucasian skin and Franz diffusion cells with the application of 0.3 mg Pt/mL in the donor solution for 24-h. After 8-h of exposure, 1.87 ng/cm2 of Pt was detected in the receptor solution with exposure to potassium hexachloroplatinate, whereas 0.47 ng/cm2 was detected with exposure to potassium tetrachloroplatinate. After 24-h of exposure the Pt retention in the skin was 1861.60 ng/cm2 and 1486.32 ng/cm2 with exposure to potassium hexa- and tetrachloroplatinate respectively. The faster rate of Pt permeation from exposure to potassium hexachloroplatinate was confirmed by the flux and permeability coefficient values. The results indicate a higher permeability and skin retention of Pt when exposed to potassium hexachloroplatinate, confirming a higher risk associated with occupational exposure to this platinum compound relative to potassium tetrachloroplatinate.

Asunto(s)

Platino (Metal) , Piel , Femenino , Humanos , Platino (Metal)/toxicidad , Compuestos de Platino , Cloruros

RESUMEN

The link between bread and wheat products and celiac disease was first recognized by Willem Dicke in the 1930s through clinical observations of his child patients. The role of gluten as the toxic factor was then proven by Drs. Dicke, Weijers and Van de Kamer in brilliant and prolonged studies in a small number of children. The Dutch Coeliac Society helped us interview surviving child subjects of these studies. Vignettes of their lives, difficulties and memories are presented in their own words. These testimonies emphasize the central role clinical observation has had in our understanding of celiac disease pathophysiology.

Asunto(s)

Enfermedad Celíaca , Niño , Humanos , Pan , Enfermedad Celíaca/diagnóstico , Glútenes , Triticum

RESUMEN

Mycobacterium tuberculosis (Mtb) infection is notoriously difficult to treat. Treatment efficacy is limited by Mtb's intrinsic drug resistance, as well as its ability to evolve acquired resistance to all antituberculars in clinical use. A deeper understanding of the bacterial pathways that influence drug efficacy could facilitate the development of more effective therapies, identify new mechanisms of acquired resistance, and reveal overlooked therapeutic opportunities. Here we developed a CRISPR interference chemical-genetics platform to titrate the expression of Mtb genes and quantify bacterial fitness in the presence of different drugs. We discovered diverse mechanisms of intrinsic drug resistance, unveiling hundreds of potential targets for synergistic drug combinations. Combining chemical genetics with comparative genomics of Mtb clinical isolates, we further identified several previously unknown mechanisms of acquired drug resistance, one of which is associated with a multidrug-resistant tuberculosis outbreak in South America. Lastly, we found that the intrinsic resistance factor whiB7 was inactivated in an entire Mtb sublineage endemic to Southeast Asia, presenting an opportunity to potentially repurpose the macrolide antibiotic clarithromycin to treat tuberculosis. This chemical-genetic map provides a rich resource to understand drug efficacy in Mtb and guide future tuberculosis drug development and treatment.

Asunto(s)

Mycobacterium tuberculosis , Tuberculosis Resistente a Múltiples Medicamentos , Tuberculosis , Antituberculosos/metabolismo , Antituberculosos/farmacología , Genómica , Humanos , Tuberculosis/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/genética

RESUMEN

Macrophages are a protective replicative niche for Mycobacterium tuberculosis (Mtb) but can kill the infecting bacterium when appropriately activated. To identify mechanisms of clearance, we compared levels of bacterial restriction by human macrophages after treatment with 26 compounds, including some currently in clinical trials for tuberculosis. All-trans-retinoic acid (ATRA), an active metabolite of vitamin A, drove the greatest increase in Mtb control. Bacterial clearance was transcriptionally and functionally associated with changes in macrophage cholesterol trafficking and lipid metabolism. To determine how these macrophage changes affected bacterial control, we performed the first Mtb CRISPR interference screen in an infection model, identifying Mtb genes specifically required to survive in ATRA-activated macrophages. These data showed that ATRA treatment starves Mtb of cholesterol and the downstream metabolite propionyl coenzyme A (propionyl-CoA). Supplementation with sources of propionyl-CoA, including cholesterol, abrogated the restrictive effect of ATRA. This work demonstrates that targeting the coupled metabolism of Mtb and the macrophage improves control of infection and that it is possible to genetically map the mode of bacterial death using CRISPR interference. IMPORTANCE Tuberculosis, caused by the bacterium Mycobacterium tuberculosis, is a leading cause of death due to infectious disease. Improving the immune response to tuberculosis holds promise for fighting the disease but is limited by our lack of knowledge as to how the immune system kills M. tuberculosis. Our research identifies a potent way to make relevant immune cells more effective at fighting M. tuberculosis and then uses paired human and bacterial genomic methods to determine the mechanism of that improved bacterial clearance.

Asunto(s)

Mycobacterium tuberculosis , Tuberculosis , Humanos , Mycobacterium tuberculosis/genética , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Macrófagos/microbiología , Tuberculosis/microbiología , Acilcoenzima A/metabolismo , Tretinoina/metabolismo , Tretinoina/farmacología , Colesterol/metabolismo

RESUMEN

Antibacterial agents target the products of essential genes but rarely achieve complete target inhibition. Thus, the all-or-none definition of essentiality afforded by traditional genetic approaches fails to discern the most attractive bacterial targets: those whose incomplete inhibition results in major fitness costs. In contrast, gene "vulnerability" is a continuous, quantifiable trait that relates the magnitude of gene inhibition to the effect on bacterial fitness. We developed a CRISPR interference-based functional genomics method to systematically titrate gene expression in Mycobacterium tuberculosis (Mtb) and monitor fitness outcomes. We identified highly vulnerable genes in various processes, including novel targets unexplored for drug discovery. Equally important, we identified invulnerable essential genes, potentially explaining failed drug discovery efforts. Comparison of vulnerability between the reference and a hypervirulent Mtb isolate revealed incomplete conservation of vulnerability and that differential vulnerability can predict differential antibacterial susceptibility. Our results quantitatively redefine essential bacterial processes and identify high-value targets for drug development.

Asunto(s)

Regulación Bacteriana de la Expresión Génica , Genoma Bacteriano , Mycobacterium tuberculosis/genética , Aminoacil-ARNt Sintetasas/metabolismo , Antituberculosos/farmacología , Teorema de Bayes , Evolución Biológica , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas/genética , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Silenciador del Gen/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/efectos de los fármacos , ARN Guía de Kinetoplastida/genética

RESUMEN

BACKGROUND: The correlation between different methods for the detection of pneumococcal polysaccharide vaccine (PPV) responses to diagnose specific polysaccharide antibody deficiency (SAD) is poor and the criteria for defining a normal response lack consensus. We previously proposed fifth percentile (p5) values of PPV responses as a new cutoff for SAD. OBJECTIVE: To analyze the association of SAD (determined by either World Health Organization (WHO)-standardized ELISA or multiplex bead-based assay) with abnormal response to Salmonella (S.) typhi Vi vaccination in a cohort of patients with recurrent infections. METHODS: Ninety-four patients with a clinical history suggestive of antibody deficiency received PPV and S. typhi Vi vaccines. Polysaccharide responses to either 3 or 18 pneumococcal serotypes were measured by either the WHO ELISA or a multiplex in-house bead-based assay. Anti-S. typhi Vi IgG were measured by a commercial ELISA kit. Allohemagglutinins (AHA) were measured by agglutination method. RESULTS: Based on the American Academy of Allergy, Asthma and Immunology (AAAAI) criteria for WHO ELISA, 18/94 patients were diagnosed with SAD and 22/93 based on serotype-specific p5 cutoffs for bead-based assay. The association between the two methods was significant, with 10 subjects showing abnormal response according to both techniques. Abnormal response to S. typhi Vi vaccination was found in 7 patients, 6 of which had SAD. No correlation was found between polysaccharide response and AHA, age, or clinical phenotype. CONCLUSION: The lack of evidence-based gold standards for the diagnosis of SAD represents a challenge in clinical practice. In our cohort, we confirmed the insufficient correlation between different methods of specific PPV response measurement, and showed that the S. typhi Vi response was not contributive. Caution in the interpretation of results is warranted until more reliable diagnostic methods can be validated.

Asunto(s)

Anticuerpos Antibacterianos/inmunología , Vacunas Neumococicas/inmunología , Polisacáridos Bacterianos/inmunología , Enfermedades de Inmunodeficiencia Primaria/inmunología , Salmonella typhi/inmunología , Adolescente , Adulto , Niño , Preescolar , Humanos , Inmunoglobulina G/inmunología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Serogrupo , Streptococcus pneumoniae/inmunología , Vacunas Tifoides-Paratifoides/inmunología , Vacunación/métodos , Adulto Joven

RESUMEN

DOCK2 is a guanine-nucleotide-exchange factor for Rac proteins. Activated Rac serves various cellular functions including the reorganization of the actin cytoskeleton in lymphocytes and neutrophils and production of reactive oxygen species in neutrophils. Since 2015, six unrelated patients with combined immunodeficiency and early-onset severe viral infections caused by bi-allelic loss-of-function mutations in DOCK2 have been described. Until now, the function of phagocytes, specifically neutrophils, has not been assessed in human DOCK2 deficiency. Here, we describe a new kindred with four affected siblings harboring a homozygous splice-site mutation (c.2704-2 A > C) in DOCK2. The mutation results in alternative splicing and a complete loss of DOCK2 protein expression. The patients presented with leaky severe combined immunodeficiency or Omenn syndrome. The novel mutation affects EBV-B cell migration and results in NK cell dysfunction similar to previous observations. Moreover, both cytoskeletal rearrangement and reactive oxygen species production are partially impaired in DOCK2-deficient neutrophils.

Asunto(s)

Linfocitos B/inmunología , Proteínas Activadoras de GTPasa/genética , Factores de Intercambio de Guanina Nucleótido/genética , Células Asesinas Naturales/inmunología , Neutrófilos/inmunología , Eliminación de Secuencia/genética , Inmunodeficiencia Combinada Grave/genética , Empalme Alternativo/genética , Humanos , Estrés Oxidativo , Linaje

RESUMEN

Innate immunity contributes to host defense through all cell types and relies on their shared germline genetic background, whereas adaptive immunity operates through only 3 main cell types, αß T cells, γδ T cells, and B cells, and relies on their somatic genetic diversification of antigen-specific responses. Human inborn errors of innate immunity often underlie infectious diseases. The range and nature of infections depend on the mutated gene, the deleteriousness of the mutation, and other ill-defined factors. Most known inborn errors of innate immunity to infection disrupt the development or function of leukocytes other than T and B cells, but a growing number of inborn errors affect cells other than circulating and tissue leukocytes. Here we review inborn errors of innate immunity that have been recently discovered or clarified. We highlight the immunologic implications of these errors.

Asunto(s)

Enfermedades Transmisibles/genética , Enfermedades Genéticas Congénitas/inmunología , Inmunidad Innata/genética , Leucocitos/fisiología , Mutación/genética , Animales , Enfermedades Transmisibles/inmunología , Humanos , Interferones/metabolismo , FN-kappa B/genética , Fagocitosis , Transducción de Señal , Receptores Toll-Like/genética

RESUMEN

Isolated congenital asplenia (ICA) is the only known human developmental defect exclusively affecting a lymphoid organ. In 2013, we showed that private deleterious mutations in the protein-coding region of RPSA, encoding ribosomal protein SA, caused ICA by haploinsufficiency with complete penetrance. We reported seven heterozygous protein-coding mutations in 8 of the 23 kindreds studied, including 6 of the 8 multiplex kindreds. We have since enrolled 33 new kindreds, 5 of which are multiplex. We describe here 11 new heterozygous ICA-causing RPSA protein-coding mutations, and the first two mutations in the 5'-UTR of this gene, which disrupt mRNA splicing. Overall, 40 of the 73 ICA patients (55%) and 23 of the 56 kindreds (41%) carry mutations located in translated or untranslated exons of RPSA. Eleven of the 43 kindreds affected by sporadic disease (26%) carry RPSA mutations, whereas 12 of the 13 multiplex kindreds (92%) carry RPSA mutations. We also report that 6 of 18 (33%) protein-coding mutations and the two (100%) 5'-UTR mutations display incomplete penetrance. Three mutations were identified in two independent kindreds, due to a hotspot or a founder effect. Finally, RPSA ICA-causing mutations were demonstrated to be de novo in 7 of the 23 probands. Mutations in RPSA exons can affect the translated or untranslated regions and can underlie ICA with complete or incomplete penetrance.

Asunto(s)

Exones , Síndromes de Inmunodeficiencia/genética , Mutación , Penetrancia , Biosíntesis de Proteínas/genética , Empalme del ARN/genética , Receptores de Laminina/genética , Proteínas Ribosómicas/genética , Bazo/anomalías , Regiones no Traducidas 5' , Femenino , Efecto Fundador , Heterocigoto , Humanos , Síndromes de Inmunodeficiencia/metabolismo , Masculino , Enfermedades de Inmunodeficiencia Primaria , Receptores de Laminina/biosíntesis , Proteínas Ribosómicas/biosíntesis , Bazo/metabolismo

RESUMEN

Vitamin A intoxication is a rare cause of liver disease, but the risk increases in patients with underlying liver dysfunction. We present a patient with Shwachman-Diamond Syndrome who developed liver fibrosis, portal hypertension and very severe hepatopulmonary syndrome as a consequence of chronic vitamin A intoxication. She underwent successful liver transplantation with complete resolution of the pulmonary shunting.

Asunto(s)

Enfermedades de la Médula Ósea/cirugía , Insuficiencia Pancreática Exocrina/cirugía , Síndrome Hepatopulmonar/etiología , Síndrome Hepatopulmonar/cirugía , Lipomatosis/cirugía , Hepatopatías/complicaciones , Trasplante de Hígado/métodos , Vitamina A/toxicidad , Niño , Preescolar , Femenino , Humanos , Hepatopatías/etiología , Síndrome de Shwachman-Diamond

RESUMEN

The study of inborn errors of immunity is based on a comprehensive clinical description of the patient's phenotype and the elucidation of the underlying molecular mechanisms and their genetic etiology. Deciphering the pathogenesis is key to genetic counseling and the development of targeted therapy. This review shows the power of whole-exome sequencing in detecting inborn errors of immunity along five central steps taken in whole-exome sequencing analysis. In parallel, we highlight the challenges for the clinical and scientific use of the method and how these hurdles are currently being addressed. We end by ruminating on major areas in the field open to future research.

RESUMEN

Deficiency of adenosine deaminase 2 (DADA2) is caused by biallelic deleterious mutations in CECR1 DADA2 results in variable autoinflammation and vasculopathy (recurrent fevers, livedo reticularis, polyarteritis nodosa, lacunar ischemic strokes, and intracranial hemorrhages), immunodeficiency and bone marrow failure. Tumor necrosis factor-α blockade is the treatment of choice for the autoinflammation and vascular manifestations. Hematopoietic stem cell transplantation (HSCT) represents a potential definitive treatment. We present a cohort of 14 patients from 6 countries who received HSCT for DADA2. Indication for HSCT was bone marrow dysfunction or immunodeficiency. Six of 14 patients had vasculitis pre-HSCT. The median age at HSCT was 7.5 years. Conditioning regimens were myeloablative (9) and reduced intensity (5). Donors were HLA-matched sibling (n = 1), HLA-matched unrelated (n = 9), HLA-mismatched unrelated (n = 3), and HLA haploidentical sibling (n = 1). All patients are alive and well with no new vascular events and resolution of hematological and immunological phenotype at a median follow-up of 18 months (range, 5 months to 13 years). Plasma ADA2 enzyme activity normalized in those tested post-HSCT (7/7), as early as day +14 (myeloid engraftment). Post-HSCT hematological autoimmunity (cytopenias) was reported in 4 patients, acute graft-versus-host disease grade 1 in 2, grade 2 in 3, and grade 3-4 in 1, and moderate chronic graft-versus-host disease in 1 patient. In conclusion, in 14 patients, HSCT was an effective and definitive treatment of DADA2.

Asunto(s)

Adenosina Desaminasa/genética , Trasplante de Células Madre Hematopoyéticas/métodos , Síndromes de Inmunodeficiencia/genética , Síndromes de Inmunodeficiencia/terapia , Péptidos y Proteínas de Señalización Intercelular/genética , Mutación , Adenosina Desaminasa/sangre , Adenosina Desaminasa/metabolismo , Adolescente , Niño , Preescolar , Estudios de Cohortes , Femenino , Enfermedad Injerto contra Huésped/diagnóstico , Enfermedad Injerto contra Huésped/etiología , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Humanos , Síndromes de Inmunodeficiencia/enzimología , Lactante , Recién Nacido , Péptidos y Proteínas de Señalización Intercelular/sangre , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Masculino , Fenotipo , Acondicionamiento Pretrasplante/métodos

RESUMEN

BACKGROUND: The reason why Cystic Fibrosis (CF) is the most common fatal genetic disease among Caucasians has been incompletely studied. We aimed at deepening the hypothesis that CF carriers have a relative protection against Mycobacterium tuberculosis (Mtb) infection. METHODS: Applying spatial epidemiology, we studied the link between CF carriership rate and tuberculosis (TB) incidence in Brazil. We corrected for 5 potential environmental and 2 immunological confounders in this relation: monthly income, sanitary provisions, literacy rates, racial composition and population density along with AIDS incidence rates and diabetes mellitus type 2. Smoking data were incomplete and not available for analysis. RESULTS: A significant, negative correlation between CF carriership rate and TB incidence, independent of any of the seven confounders was found. CONCLUSION: We provide exploratory support for the hypothesis that carrying a single CFTR mutation arms against Mtb infections.

Asunto(s)

Fibrosis Quística/genética , Heterocigoto , Tuberculosis/epidemiología , Brasil/epidemiología , Fibrosis Quística/epidemiología , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Humanos , Masculino , Mutación , Tuberculosis/genética , Población Blanca/genética

RESUMEN

BACKGROUND: Serotype-specific antibody responses to unconjugated pneumococcal polysaccharide vaccine (PPV) evaluated by a World Health Organization (WHO)-standardized enzyme-linked immunosorbent assay (ELISA) are the gold standard for diagnosis of specific polysaccharide antibody deficiency (SAD). The American Academy of Allergy, Asthma and Immunology (AAAAI) has proposed guidelines to interpret the PPV response measured by ELISA, but these are based on limited evidence. Additionally, ELISA is costly and labor-intensive. Measurement of antibody response to Salmonella typhi (S. typhi) Vi vaccine and serum allohemagglutinins (AHA) have been suggested as alternatives. However, there are no large cohort studies and cutoff values are lacking. OBJECTIVE: To establish cutoff values for antipneumococcal polysaccharide antibody response, anti-S. typhi Vi antibody, and AHA. METHODS: One hundred healthy subjects (10-55 years) were vaccinated with PPV and S. typhi Vi vaccine. Blood samples were obtained prior to and 3-4 weeks after vaccination. Polysaccharide responses to 3 serotypes were measured by WHO ELISA and to 12 serotypes by an in-house bead-based multiplex assay. Anti-S. typhi Vi IgG were measured with a commercial ELISA kit. AHA were measured by agglutination method. RESULTS: Applying AAAAI criteria, 30% of healthy subjects had a SAD. Using serotype-specific fifth percentile (p5) cutoff values for postvaccination IgG and fold increase pre- over postvaccination, only 4% of subjects had SAD. One-sided 95% prediction intervals for anti-S. typhi Vi postvaccination IgG (≥11.2 U/ml) and fold increase (≥2) were established. Eight percent had a response to S. typhi Vi vaccine below these cutoffs. AHA titer p5 cutoffs were ½ for anti-B and » for anti-A. CONCLUSION: We establish reference cutoff values for interpretation of PPV response measured by bead-based assay, cutoff values for S. typhi Vi vaccine responses, and normal values for AHA. For the first time, the intraindividual consistency of all three methods is studied in a large cohort.

RESUMEN

BACKGROUND: The diagnosis of Cystic Fibrosis (CF) is by consensus based on the same parameters in all patients, yet the influence of ethnicity has only scarcely been studied. We aimed at elucidating the impact of Asian descent on the diagnosis of CF. METHODS: We performed a retrospective analysis of the CFTR2 and UK CF databases for clinical phenotype, sweat chloride values and CFTR mutations and compared the diagnostic characteristics of Asian to non-Asian patients with CF. RESULTS: Asian patients with CF do not have a worse clinical phenotype. The repeatedly reported lower FEV1 of Asian patients with CF is attributable to the influence of ethnicity on lung function in general. However, pancreatic sufficiency is more common in Asian patients with CF. The diagnosis of CF in people with Asian ancestry is heterogeneous as mean sweat chloride values are lower (92±26 versus 99±22mmol/L in controls) and 14% have sweat chloride values below 60mmol/L (versus 6% in non-Asians). Also, CFTR mutations differ from those in Caucasians: 55% of British Asian patients with CF do not have one mutation included in the routine newborn screening panel. CONCLUSIONS: Bringing together the largest cohort of patients with CF and Asian ethnicity, we demonstrate that Asian roots impact on all three CF diagnostic pillars. These findings have implications for clinical practice in the increasingly ethnically diverse Western population.

Asunto(s)

Pueblo Asiatico , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Fibrosis Quística , Sudor/química , Adolescente , Adulto , Pueblo Asiatico/genética , Pueblo Asiatico/estadística & datos numéricos , Preescolar , Cloruros/análisis , Fibrosis Quística/diagnóstico , Fibrosis Quística/etnología , Fibrosis Quística/genética , Fibrosis Quística/fisiopatología , Femenino , Pruebas Genéticas , Humanos , Recién Nacido , Mediciones del Volumen Pulmonar/métodos , Masculino , Mutación , Tamizaje Neonatal/ética , Tamizaje Neonatal/métodos , Páncreas/fisiopatología , Sistema de Registros/estadística & datos numéricos , Reino Unido/epidemiología

Asunto(s)

Inmunoglobulina E/biosíntesis , Deficiencia de Mevalonato Quinasa/diagnóstico , Mutación Missense/genética , Factor de Transcripción STAT3/genética , Linfocitos T/patología , Niño , Trastornos de los Cromosomas , Análisis Mutacional de ADN , Diagnóstico Precoz , Genes Dominantes , Humanos , Inmunoglobulina E/sangre , Recuento de Linfocitos , Masculino , Deficiencia de Mevalonato Quinasa/genética , Patología Molecular , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo