Genetic mannose binding lectin deficiency is associated with airway microbiota diversity and reduced exacerbation frequency in COPD.

BACKGROUND: In cystic fibrosis and bronchiectasis, genetic mannose binding lectin (MBL) deficiency is associated with increased exacerbations and earlier mortality; associations in COPD are less clear. Preclinical data suggest MBL interferes with phagocytosis of Haemophilus influenzae, a key COPD pathogen. We investigated whether MBL deficiency impacted on clinical outcomes or microbiota composition in COPD. METHODS: Patients with COPD (n=1796) underwent MBL genotyping; linkage to health records identified exacerbations, lung function decline and mortality. A nested subcohort of 141 patients, followed for up to 6 months, was studied to test if MBL deficiency was associated with altered sputum microbiota, through 16S rRNA PCR and sequencing, or airway inflammation during stable and exacerbated COPD. FINDINGS: Patients with MBL deficiency with COPD were significantly less likely to have severe exacerbations (incidence rate ratio (IRR) 0.66, 95% CI 0.48 to 0.90, p=0.009), or to have moderate or severe exacerbations (IRR 0.77, 95% CI 0.60 to 0.99, p=0.047). MBL deficiency did not affect rate of FEV1 decline or mortality. In the subcohort, patients with MBL deficiency had a more diverse lung microbiota (p=0.008), and were less likely to be colonised with Haemophilus spp. There were lower levels of airway inflammation in patients with MBL deficiency. INTERPRETATION: Patients with MBL deficient genotype with COPD have a lower risk of exacerbations and a more diverse lung microbiota. This is the first study to identify a genetic association with the lung microbiota in COPD.

European Respiratory Society guidelines for the management of adult bronchiectasis.

Bronchiectasis in adults is a chronic disorder associated with poor quality of life and frequent exacerbations in many patients. There have been no previous international guidelines.The European Respiratory Society guidelines for the management of adult bronchiectasis describe the appropriate investigation and treatment strategies determined by a systematic review of the literature.A multidisciplinary group representing respiratory medicine, microbiology, physiotherapy, thoracic surgery, primary care, methodology and patients considered the most relevant clinical questions (for both clinicians and patients) related to management of bronchiectasis. Nine key clinical questions were generated and a systematic review was conducted to identify published systematic reviews, randomised clinical trials and observational studies that answered these questions. We used the GRADE approach to define the quality of the evidence and the level of recommendations. The resulting guideline addresses the investigation of underlying causes of bronchiectasis, treatment of exacerbations, pathogen eradication, long term antibiotic treatment, anti-inflammatories, mucoactive drugs, bronchodilators, surgical treatment and respiratory physiotherapy.These recommendations can be used to benchmark quality of care for people with bronchiectasis across Europe and to improve outcomes.

Neutrophil Elastase Activity Is Associated with Exacerbations and Lung Function Decline in Bronchiectasis.

RATIONALE: Sputum neutrophil elastase and serum desmosine, which is a linked marker of endogenous elastin degradation, are possible biomarkers of disease severity and progression in bronchiectasis. This study aimed to determine the association of elastase activity and desmosine with exacerbations and lung function decline in bronchiectasis. METHODS: This was a single-center prospective cohort study using the TAYBRIDGE (Tayside Bronchiectasis Registry Integrating Datasets, Genomics, and Enrolment into Clinical Trials) registry in Dundee, UK. A total of 433 patients with high-resolution computed tomography-confirmed bronchiectasis provided blood samples for desmosine measurement, and 381 provided sputum for baseline elastase activity measurements using an activity-based immunosassay and fluorometric substrate assay. Candidate biomarkers were tested for their relationship with cross-sectional markers of disease severity, and with future exacerbations, mortality and lung function decline over 3 years. MEASUREMENT AND MAIN RESULTS: Elastase activity in sputum was associated with the bronchiectasis severity index (r = 0.49; P < 0.0001) and was also correlated with the Medical Research Council dyspnea score (r = 0.34; P < 0.0001), FEV1% predicted (r = -0.33; P < 0.0001), and the radiological extent of bronchiectasis (r = 0.29; P < 0.0001). During a 3-year follow-up, elevated sputum elastase activity was associated with a higher frequency of exacerbations (P < 0.0001) but was not independently associated with mortality. Sputum elastase activity was independently associated with FEV1 decline (ß coefficient, -0.139; P = 0.001). Elastase showed good discrimination for severe exacerbations with an area under the curve of 0.75 (95% confidence interval [CI], 0.72-0.79) and all-cause mortality (area under the curve, 0.70; 95% CI, 0.67-0.73). Sputum elastase activity increased at exacerbations (P = 0.001) and was responsive to treatment with antibiotics. Desmosine was correlated with sputum elastase (r = 0.42; P < 0.0001) and was associated with risk of severe exacerbations (hazard ratio 2.7; 95% CI, 1.42-5.29; P = 0.003) but not lung function decline. CONCLUSIONS: Sputum neutrophil elastase activity is a biomarker of disease severity and future risk in adults with bronchiectasis.

Differences in inflammatory bowel disease phenotype between South Asians and Northern Europeans living in North West London, UK.

OBJECTIVES: The incidence and prevalence of inflammatory bowel disease (IBD) is increasing throughout Asia. Since the 1950s, there has been substantial migration from South Asia (India, Pakistan, and Bangladesh) to the United Kingdom. The aim of this study was to define the clinical phenotype of IBD in UK South Asians living in North West London, and to compare the results with a white Northern European IBD cohort. METHODS: The phenotypic details of 367 South Asian IBD patients (273 ulcerative colitis (UC) and 94 Crohn's disease (CD)), undergoing active follow-up in five North West London hospitals, were compared with those of 403 consecutively collected white Northern European IBD patients (188 UC and 215 CD). RESULTS: The phenotype of IBD differed significantly between the two populations. 63.0% of South Asian UC patients had extensive colitis compared with 42.5% of the Northern European cohort (P < 0.0001). Proctitis was uncommon in South Asian UC patients (9.9 vs. 26.1% in Northern European patients, P<0.0001). In the South Asian CD cohort, disease location was predominantly colonic (46.8%). CD behavior differed significantly between the groups, with less penetrating disease compared with Northern Europeans (P=0.01) and a reduced need for surgery (P=0.003). CONCLUSIONS: The phenotype of IBD in South Asians living in North West London is significantly different from that of a white Northern European IBD cohort. Knowledge of ethnic variations in disease phenotype may help to identify key genetic, environmental, and behavioral factors contributing to the development of IBD.

Differences in gut microbial metabolism are responsible for reduced hippurate synthesis in Crohn's disease.

BACKGROUND: Certain urinary metabolites are the product of gut microbial or mammalian metabolism; others, such as hippurate, are mammalian-microbial 'co-metabolites'. It has previously been observed that Crohn's disease (CD) patients excrete significantly less hippurate than controls. There are two stages in the biosynthesis of this metabolite: 1) gut microbial metabolism of dietary aromatic compounds to benzoate, and 2) subsequent hepatorenal conjugation of benzoate with glycine, forming hippurate. Differences in such urinary co-metabolites may therefore reflect systemic consequences of altered gut microbial metabolism, though altered host metabolic pathways may also be involved. METHODS: It was hypothesised that reduced hippurate excretion in CD patients was due to alterations in the gut microbiota, and not differences in dietary benzoate, nor defective host enzymatic conjugation of benzoate. 5 mg/kg sodium benzoate were administered orally to 16 CD patients and 16 healthy controls on a low-benzoate diet. Baseline and peak urinary hippurate excretion were measured. RESULTS: Baseline hippurate levels were significantly lower in the CD patients (p = 0.0009). After benzoate ingestion, peak urinary levels of hippurate did not differ significantly between the cohorts. Consequently the relative increase in excretion was significantly greater in CD (p = 0.0007). CONCLUSIONS: Lower urinary hippurate levels in CD are not due to differences in dietary benzoate. A defect in the enzymatic conjugation of benzoate in CD has been excluded, strongly implicating altered gut microbial metabolism as the cause of decreased hippurate levels in CD.

Characterization of inflammatory bowel disease with urinary metabolic profiling.

OBJECTIVES: Distinguishing between the inflammatory bowel disease (IBD), Crohn's disease (CD), and ulcerative colitis (UC) is important for both management and prognostic reasons. Discrimination using noninvasive techniques could be an adjunct to conventional diagnostics. Differences have been shown between the intestinal microbiota of CD and UC patients and controls; the gut bacteria influence specific urinary metabolites that are quantifiable using proton high-resolution nuclear magnetic resonance (NMR) spectroscopy. This study tested the hypothesis that such metabolites differ between IBD and control cohorts, and that using multivariate pattern-recognition analysis, the cohorts could be distinguished by urine NMR spectroscopy. METHODS: NMR spectra were acquired from urine samples of 206 Caucasian subjects (86 CD patients, 60 UC patients, and 60 healthy controls). Longitudinal samples were collected from 75 individuals. NMR resonances specific for metabolites influenced by the gut microbes were studied, including hippurate, formate, and 4-cresol sulfate. Multivariate analysis of all urinary metabolites involved principal components analysis (PCA) and partial least squares discriminant analysis (PLS-DA). RESULTS: Hippurate levels were lowest in CD patients and differed significantly between the three cohorts (P<0.0001). Formate levels were higher and 4-cresol sulfate levels lower in CD patients than in UC patients or controls (P=0.0005 and P=0.0002, respectively). PCA revealed clustering of the groups; PLS-DA modeling was able to distinguish the cohorts. These results were independent of medication and diet and were reproducible in the longitudinal cohort. CONCLUSIONS: Specific urinary metabolites related to gut microbial metabolism differ between CD patients, UC patients, and controls. The emerging technique of urinary metabolic profiling with multivariate analysis was able to distinguish these cohorts.

Association between heat shock protein 70/Hom genetic polymorphisms and uveitis in patients with sarcoidosis.

PURPOSE: The predisposition to sarcoidosis, a systemic granulomatous disorder of unknown etiology, is genetically determined, and genetics appears also to drive the disease down distinct phenotypic pathways. This study was undertaken to test the hypothesis that sarcoidosis-related uveitis represents a genetically distinct disease subset, by investigating single nucleotide polymorphisms (SNPs) in the HSP-70/1 and HSP-70/Hom genes. HSP70 molecules play a key role in the immune response by functioning both as chaperones and as inducers of proinflammatory cytokine secretion. METHODS: By sequence-specific primers-polymerase chain reaction (SSP-PCR) five SNPs were evaluated in 270 white patients with sarcoidosis, including 88 with sarcoid-related uveitis, and in 347 matched control subjects. One hundred twenty-five patients with idiopathic anterior uveitis (IAU) and 56 with idiopathic intermediate uveitis (IIU) were also included in the study as disease control subjects. RESULTS: The HSP-70/Hom rs2075800 G allele frequency was higher in the sarcoid-uveitis group than in both the sarcoid-non-uveitis and control groups (83% vs. 71%, OR = 2.00, P(c) = 0.01; and 83% vs. 66%, OR = 2.45, P(c) = 0.00005, respectively). Similar results were observed when considering the carriage frequency of the associated haplotype (HSP-70 haplotype 2) across the three study groups (47% vs. 29%, OR = 2.17, P(c) = 0.03; and 47% vs. 21%, OR = 3.26, P(c) = 0.0003, respectively). In addition, the carriage frequency of the HSP-70 haplotype 2 discriminated among sarcoid-related uveitis, IAU, and IIU (47% vs. 19%, OR = 3.26, P(c) = 0.001; and 47% vs. 23%, OR = 2.81, P(c) = 0.04, respectively). CONCLUSIONS: A strong association was found between HSP-70/Hom rs2075800 G and uveitis in patients with sarcoidosis. Further studies are needed to understand the molecular mechanisms underlying this association.

Genetics of inflammatory bowel disease: the role of the HLA complex.

The human leucocyte antigen (HLA) complex on chromosome 6p21.3 is the most extensively studied genetic region in Inflammatory bowel disease (IBD). Consistent evidence of linkage to IBD3 (6p21.1-23), an area which encompasses the HLA complex, has been demonstrated for both Crohn's disease and ulcerative colitis, and a number of replicated associations with disease susceptibility and phenotype have recently emerged. However, despite these efforts the HLA susceptibility gene (s) for IBD remain elusive, a consequence of strong linkage disequilibrium, extensive polymorphism and high gene density across this region. This article reviews current knowledge of the role of HLA complex genes in IBD susceptibility and phenotype, and discusses the factors currently limiting the translation of this knowledge to clinical practice.

A functional CD8+ cell assay reveals individual variation in CD8+ cell antiviral efficacy and explains differences in human T-lymphotropic virus type 1 proviral load.

The CD8+ lymphocyte response is a main component of host immunity, yet it is difficult to quantify its contribution to the control of persistent viruses. Consequently, it remains controversial as to whether CD8+ cells have a biologically significant impact on viral burden and disease progression in infections such as human immunodeficiency virus-1 and human T-lymphotropic virus type I (HTLV-I). Experiments to ascertain the impact of CD8+ cells on viral burden based on CD8+ cell frequency or specificity alone give inconsistent results. Here, an alternative approach was developed that directly quantifies the impact of CD8+ lymphocytes on HTLV-I proviral burden by measuring the rate at which HTLV-I-infected CD4+ cells were cleared by autologous CD8+ cells ex vivo. It was demonstrated that CD8+ cells reduced the lifespan of infected CD4+ cells to 1 day, considerably shorter than the 30 day lifespan of uninfected cells in vivo. Furthermore, it was shown that HTLV-I-infected individuals vary considerably in the rate at which their CD8+ cells clear infected cells, and that this was a significant predictor of their HTLV-I proviral load. Forty to 50 % of between-individual variation in HTLV-I proviral load was explained by variation in the rate at which CD8+ cells cleared infected cells. This novel approach demonstrates that CD8+ cells are a major determinant of HTLV-I proviral load. This assay is applicable to quantifying the CD8+ cell response to other viruses and malignancies and may be of particular importance in assessing vaccines.

Polymorphism in the interleukin-10 promoter affects both provirus load and the risk of human T lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis.

To investigate non-human leukocyte antigen candidate genes that influence the outcome of human T cell lymphotropic virus (HTLV) type I infection, we analyzed 6 single-nucleotide polymorphisms in the interleukin (IL)-10 promoter region in 280 patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and 255 HTLV-I-seropositive asymptomatic carriers from an area where HTLV-I is endemic. The IL-10 -592 A allele, which shows lower HTLV-I Tax-induced transcriptional activity than the C allele in the Jurkat T cell line, was associated with a >2-fold reduction in the odds of developing HAM/TSP (P=.011; odds ratio [OR], 0.50 [95% confidence interval, 0.30-0.86]) by reducing the provirus load in the whole cohort (P=.009, analysis of variance). Given the OR and the observed frequency of IL-10 -592 A, we demonstrate that this allele prevents approximately 44.7% (standard deviation, +/-13.1%) of potential cases of HAM/TSP, which indicates that it defines one component of the genetic susceptibility to HAM/TSP in the cohort.

Behçet's disease.

Behçet's disease is a systemic vasculitis characterized by recurrent oral and genital ulcers, and ocular inflammation, and which may involve the joints, skin, central nervous system and gastrointestinal tract. It is most common in those of Mediterranean and Eastern origin, although it also affects Caucasians. The aetiology of the disease remains unknown, but the most widely held hypothesis of disease pathogenesis is that of a profound inflammatory response triggered by an infectious agent in a genetically susceptible host. Supporting this is the consistent association of disease susceptibility with polymorphisms in the human leukocyte antigen complex, particularly HLA-B*51. The diagnosis is a clinical one, and although there is no single laboratory test specific for the diagnosis of Behçet's disease, the 1990 classification criteria perform well in a clinical context. Whereas many favoured treatments for single or multisystem disease still lack a sound evidential base, cyclosporin and azathioprine perform well in clinical trials, and evidence is accumulating for the efficacy of anti-tumour necrosis factor therapy in particular clinical situations. This review will focus on recent developments in the understanding of disease pathogenesis and clinical diagnosis, and review the evidence base for both established and new agents in the therapeutic strategy.

The impact of endothelial nitric oxide synthase polymorphisms on long-term renal allograft outcome.

A major manifestation of chronic allograft failure (CAF) is the accelerated onset of atherosclerotic lesions within the graft. Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene have been implicated in the pathogenesis of native atherosclerosis. This study tested the hypothesis that polymorphisms in eNOS are associated with susceptibility to CAF after cadaveric renal transplantation. The patient cohort comprised 140 renal transplant recipients who had received their transplants between 1985 and 1997 at the Oxford Transplant Centre and included 61 patients with biopsy-proven CAF and 79 with stable graft function for at least 10 years (long-term survivors, LTS). Genotyping for one polymorphism in the promoter region and two polymorphisms in the coding regions of the eNOS gene was performed by polymerase chain reaction with sequence-specific primers (PCR-SSP). No association was found between any genetic variant and the development of CAF, even after stratification for other known risk factors. Statistical analysis revealed that all three polymorphisms were closely linked. We conclude that recipient eNOS gene polymorphisms do not alter the risk of CAF after renal transplantation.

Mapping the HLA association in Behçet's disease: a role for tumor necrosis factor polymorphisms?

OBJECTIVE: Experimental evidence suggests that inappropriate regulation of tumor necrosis factor alpha (TNF alpha) may play a role in the pathogenesis of Behçet's disease (BD). This is supported by recent reports highlighting the efficacy of anti-TNF alpha agents in the treatment of this disease. The TNF gene is encoded in the class III region of the HLA complex adjacent to HLA-B. This genetic proximity to a gene that is already widely implicated in disease susceptibility led us to investigate the association between TNF promoter polymorphisms and susceptibility to BD. METHODS: We studied 133 UK white Caucasoid patients with BD and 354 healthy controls. We attempted to dissect the contribution of individual polymorphisms in this gene-dense region by linkage disequilibrium mapping across 6 adjacent genes. RESULTS: We report a novel association with the TNF promoter allele TNF-1031C. Subsequent analysis identified 2 extended HLA haplotypes associated with BD. One of them contained the previously recognized susceptibility gene HLA-B*51, while the other was defined by HLA-B*5701. Both of these haplotypes contained the TNF promoter polymorphism -1031C, an allele that was associated with disease even in individuals who did not carry either HLA-B*51 or HLA-B*5701. CONCLUSION: The TNF-1031C allele is independently associated with susceptibility to BD in Caucasoid patients. Further studies will be required to determine the functional effects of this polymorphism, its influence in disease pathogenesis, and its role in other ethnic groups.

HLA class II polymorphisms and susceptibility to recurrent respiratory papillomatosis.

Recurrent respiratory papillomatosis (RRP) is characterised by multiple laryngeal papillomas. Left untreated, the lesions enlarge, spread, and endanger the airway. Medical treatments are unsatisfactory, and repeated surgery remains the mainstay of therapy. RRP is caused by human papillomavirus (HPV) infection. However, since oral HPV infection is common and RRP is rare, other host and/or viral factors may contribute to pathogenesis. In an attempt to identify such factors, we have investigated 60 patients. The patients were HLA class I, II, and tumor necrosis factor TNF typed by sequence-specific primer PCR, and the results compared to those for 554 healthy controls by using Fisher's exact test. Peripheral blood mononuclear cell proliferative responses of 25 controls and 10 patients to HPV-11 L1 virus-like particles (VLP) were compared. Short-term VLP-specific T-cell lines were established, and recognition of L1 was analyzed. Finally, the L1 open reading frames of HPV isolates from four patients were sequenced. Susceptibility to RRP was associated with HLA DRB1*0301 (33 of 60 patients versus 136 of 554 controls, P < 0.0001). The three most severely affected patients were homozygous for this allele. A range of T-cell proliferative responses to HPV-11 VLP were observed in DRB1*0301-positive healthy donors which were comparable to those in DRB1*0301-negative controls. Individuals with juvenile-onset RRP also mounted a range of VLP responses, and their magnitude was negatively correlated with the clinical staging score (P = 0.012 by the Spearman rank correlation). DRB1*0301-positive patients who responded to L1 recognized the same epitope as did matched controls and produced similar cytokines. Sequencing of clinical isolates excluded the possibility that nonresponsiveness was the result of mutation(s) in L1.

Polygenic control of human T lymphotropic virus type I (HTLV-I) provirus load and the risk of HTLV-I-associated myelopathy/tropical spastic paraparesis.

Human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is one outcome of infection with HTLV-I. A population association study of 229 patients with HAM/TSP and 202 healthy carriers of HTLV-I in southern Japan showed that this outcome of HTLV-I infection and the HTLV-I provirus load are under polygenic control. Of 58 polymorphic sites studied in 39 non-HLA candidate gene loci, 3 new host genetic factors that influenced the risk of HAM/TSP or the provirus load of HTLV-I were identified. The promoter TNF -863A allele predisposed to HAM/TSP, whereas SDF-1 +801A 3'UTR, and IL-15 191C alleles conferred protection. Knowledge of HTLV-I-infected individuals' ages, sex, provirus load, HTLV-I subgroup, and genotypes at the loci HLA-A, HLA-C, SDF-1, and TNF-alpha allowed for the correct identification of 88% of cases of HAM/TSP in this Japanese cohort.

The molecular classification of the clinical manifestations of Crohn's disease.

BACKGROUND & AIMS: Crohn's disease is a common inflammatory disorder of the gut characterized by variation in both location and behavior. Chromosome 16 and the HLA region on chromosome 6 have been implicated in susceptibility to disease. Mutations in the NOD2/CARD15 gene, recently identified on chromosome 16, have been associated with disease overall but are found in only 25% of patients. No data regarding their contribution to specific disease subtypes exist. Here we report a detailed genotype-phenotype analysis of 244 accurately characterized patients. METHODS: A total of 244 white patients with Crohn's disease recruited from a single center in the United Kingdom were studied. All patients were rigorously phenotyped and followed-up for a median time of 16 years. By using linkage disequilibrium mapping we studied 340 polymorphisms in 24 HLA genes and 3 NOD2/CARD15 polymorphisms. RESULTS: We show that NOD2/CARD15 mutations determine ileal disease only. We confirm that alleles on specific long-range HLA haplotypes determine overall susceptibility and describe novel genetic associations with susceptibility, location, and behavior of Crohn's disease. CONCLUSIONS: The clinical pattern of Crohn's disease may be defined by specific genotypes. This study may provide the basis for a future molecular classification of disease.