Half a Century of Wilson & Jungner: Reflections on the Governance of Population Screening.

Background: In their landmark report on the "Principles and Practice of Screening for Disease" (1968), Wilson and Jungner noted that the practice of screening is just as important for securing beneficial outcomes and avoiding harms as the formulation of principles. Many jurisdictions have since established various kinds of "screening governance organizations" to provide oversight of screening practice. Yet to date there has been relatively little reflection on the nature and organization of screening governance itself, or on how different governance arrangements affect the way screening is implemented and perceived and the balance of benefits and harms it delivers. Methods: An international expert policy workshop convened by Sturdy, Miller and Hogarth. Results: While effective governance is essential to promote beneficial screening practices and avoid attendant harms, screening governance organizations face enduring challenges. These challenges are social and ethical as much as technical. Evidence-based adjudication of the benefits and harms of population screening must take account of factors that inform the production and interpretation of evidence, including the divergent professional, financial and personal commitments of stakeholders. Similarly, when planning and overseeing organized screening programs, screening governance organizations must persuade or compel multiple stakeholders to work together to a common end. Screening governance organizations in different jurisdictions vary widely in how they are constituted, how they relate to other interested organizations and actors, and what powers and authority they wield. Yet we know little about how these differences affect the way screening is implemented, and with what consequences. Conclusions: Systematic research into how screening governance is organized in different jurisdictions would facilitate policy learning to address enduring challenges. Even without such research, informal exchange and sharing of experiences between screening governance organizations can deliver invaluable insights into the social as well as the technical aspects of governance.

Gene expression profiles induced by Salmonella infection in resistant and susceptible mice.

Mouse models have been extensively used to investigate the mechanisms of salmonellosis. However, the role of the hosts' local intestinal responses during early stages of infection remain unclear. In this study, transcript array analysis was employed to investigate regulation of gene expression in the murine intestine following oral challenge with Salmonella enterica serovar Enteritidis. Salmonella resistant C3H/HeN mice elicited only weak transcription responses in the ileum even in the presence of bacterial replication and systemic infection. This poor response was surprising given previously published results using in vitro models. Susceptible TLR4-deficient C3H/HeJ mice displayed a stronger response, suggesting a role for TLR4 in dampening the response to Salmonella. Responses of susceptible BALB/c mice were also unremarkable. In contrast, in vitro infection of murine rectal epithelial cells induced a strong transcription response consistent with previous in vitro studies. Although the pattern of genes expressed by the ileal tissue upon in vivo infection were similar in all three mouse lines, the genes up-regulated during in vitro infection were different, indicating that the responses seen in vitro do not mimic those seen in vivo. Taken together these data indicate that in vivo responses to Salmonella, at the level of the intestine, are tightly regulated by the host.

Interleukin-9 polymorphism in infants with respiratory syncytial virus infection: an opposite effect in boys and girls.

The predominance of severe respiratory syncytial virus (RSV) bronchiolitis in boys compared to girls is well known, but its mechanism is not yet understood. This is the first study focusing on gender-specific genetic factors affecting the risk of severe RSV infection using a previously described cohort. We determined 347 single-nucleotide polymorphisms (SNPs) in 470 children hospitalized for RSV infection, their parents, and 1,008 random population controls. We tested if these SNPs exerted a different effect in boys and girls by performing statistical interaction tests. Only one SNP (rs2069885) had a gender-specific significant association with RSV infection, severe enough to require hospitalization (P-value 0.00057). The major allele of this structural polymorphism in the interleukin (IL)-9 gene is associated with an increased susceptibility to severe RSV infection in boys, while there is a decreased susceptibility in girls. Haplotype analysis of two SNPs in the IL-9 gene (rs2069885 and rs1799962) showed overrepresentation of the TT haplotype in girls with severe RSV bronchiolitis requiring hospitalization indicating that this is the haplotype conferring the highest risk in girls. In conclusion, the IL-9 genetic polymorphism (rs2069885) has an opposite effect on the risk of severe RSV bronchiolitis in boys and girls. Although so far a difference in IL-9 production in boys and girls has not been reported, this study may help in explaining the different risks of severe RSV bronchiolitis in boys and girls.

Genetic susceptibility to respiratory syncytial virus bronchiolitis in preterm children is associated with airway remodeling genes and innate immune genes.

Prematurity is a risk factor for severe respiratory syncytial virus bronchiolitis. We show that genetic factors in innate immune genes (IFNA13, IFNAR2, STAT2, IL27, NFKBIA, C3, IL1RN, TLR5), in innate and adaptive immunity (IFNG), and in airway remodeling genes (ADAM33 and TGFBR1), affect disease susceptibility to a different extent in preterm children, born with underdeveloped lungs, than in term children.

Comparative gene expression profiling in two congenic mouse strains following Bordetella pertussis infection.

BACKGROUND: Susceptibility to Bordetella pertussis infection varies widely. These differences can partly be explained by genetic host factors. HcB-28 mice are more resistant to B. pertussis infection than C3H mice, which could partially be ascribed to the B. pertussis susceptibility locus-1 (Bps1) on chromosome 12. The presence of C57BL/10 genome on this locus instead of C3H genome resulted in a decreased number of bacteria in the lung. To further elucidate the role of host genetic factors, in particular in the Bps1 locus, in B. pertussis infection, and to identify candidate genes within in this region, we compared expression profiles in the lungs of the C3H and HcB-28 mouse strains following B. pertussis inoculation. Twelve and a half percent of the genomes of these mice are from a different genetic background. RESULTS: Upon B. pertussis inoculation 2,353 genes were differentially expressed in the lungs of both mouse strains. Two hundred and six genes were differentially expressed between the two mouse strains, but, remarkably, none of these were up- or down-regulated upon B. pertussis infection. Of these 206 genes, 17 were located in the Bps1 region. Eight of these genes, which showed a strong difference in gene expression between the two mouse strains, map to the immunoglobulin heavy chain complex (Igh). CONCLUSION: Gene expression changes upon B. pertussis infection are highly identical between the two mouse strains despite the differences in the course of B. pertussis infection. Because the genes that were differentially regulated between the mouse strains only showed differences in expression before infection, it appears likely that such intrinsic differences in gene regulation are involved in determining differences in susceptibility to B. pertussis infection. Alternatively, such genetic differences in susceptibility may be explained by genes that are not differentially regulated between these two mouse strains. Genes in the Igh complex, among which Igh-1a/b, are likely candidates to explain differences in susceptibility to B. pertussis. Thus, by microarray analysis we significantly reduced the number of candidate susceptibility genes within the Bps1 locus. Further work should establish the role of the Igh complex in B. pertussis infection.

Toll-like receptor 4 polymorphism associated with the response to whole-cell pertussis vaccination in children from the KOALA study.

We examined the association between haplotype tagging single-nucleotide polymorphisms in TLR4 and the pertussis toxin-specific immunoglobulin G response after whole-cell pertussis (wP) vaccination in 515 1-year-old children from the KOALA study. A lower titer was associated with the minor allele of rs2770150, supporting a role for Toll-like receptor 4 in the antibody response to wP vaccination.

Genetic susceptibility to respiratory syncytial virus bronchiolitis is predominantly associated with innate immune genes.

BACKGROUND: Respiratory syncytial virus (RSV) is a common cause of severe lower respiratory tract infection in infants. Only a proportion of children infected with RSV require hospitalization. Because known risk factors for severe disease, such as premature birth, cannot fully explain differences in disease severity, genetic factors have been implicated. METHODS: To study the complexity of RSV susceptibility and to identify the genes and biological pathways involved in its development, we performed a genetic association study involving 470 children hospitalized for RSV bronchiolitis, their parents, and 1008 random, population controls. We analyzed 384 single-nucleotide polymorphisms (SNPs) in 220 candidate genes involved in airway mucosal responses, innate immunity, chemotaxis, adaptive immunity, and allergic asthma. RESULTS: SNPs in the innate immune genes VDR (rs10735810; P=.0017), JUN (rs11688; P=.0093), IFNA5 (rs10757212; P=.0093), and NOS2 (rs1060826; P=.0031) demonstrated the strongest association with bronchiolitis. Apart from association at the allele level, these 4 SNPs also demonstrated association at the genotype level (P=.0056, P=.0285, P=.0372, and P=.0117 for the SNPs in VDR, JUN, IFNA5, and NOS2, respectively). The role of innate immunity as a process was reinforced by association of the whole group of innate immune SNPs when the global test for groups of genes was applied (P=.046). CONCLUSION: SNPs in innate immune genes are important in determining susceptibility to RSV bronchiolitis.

Lung response to Bordetella pertussis infection in mice identified by gene-expression profiling.

Host genetics determines the course of Bordetella pertussis infection in mice. Previously, we found four loci, Tlr4 and three novel loci, designated Bps 1-3, that are involved in the control of B. pertussis infection. The purpose of the present study was to identify candidate genes that could explain genetic differences in the course of B. pertussis infection, assuming that such genes are differentially regulated upon infection. We, therefore, studied the course of mRNA expression in the lungs after B. pertussis infection. Of the 22,000 genes investigated, 1,841 were significantly differentially expressed with 1,182 genes upregulated and 659 genes downregulated. Upregulated genes were involved in immune-related processes, such as the acute-phase response, antigen presentation, cytokine production, inflammation, and apoptosis, while downregulated genes were mainly involved in nonimmune processes, such as development and muscle contraction. Pathway analysis revealed the involvement of granulocyte function, toll-like receptor signaling pathway, and apoptosis. Nine of the differentially expressed genes were located in Bps-1, 13 were located in Bps-2, and 62 were located in Bps-3. We conclude that B. pertussis infection induces a wide and complex response, which appears to be partly specific for B. pertussis and partly nonspecific. We envisage that these data will be helpful in identifying polymorphic genes that affect the susceptibility and course of B. pertussis infection in humans.

Host transcription profiles upon primary respiratory syncytial virus infection.

Respiratory syncytial virus (RSV) is a common cause of severe lower respiratory tract infection in children. Severe RSV disease is related to an inappropriate immune response to RSV resulting in enhanced lung pathology which is influenced by host genetic factors. To gain insight into the early pathways of the pathogenesis of and immune response to RSV infection, we determined the transcription profiles of lungs and lymph nodes on days 1 and 3 after infection of mice. Primary RSV infection resulted in a rapid but transient innate, proinflammatory response, as exemplified by the induction of a large number of type I interferon-regulated genes and chemokine genes, genes involved in inflammation, and genes involved in antigen processing. Interestingly, this response is much stronger on day 1 than on day 3 after infection, indicating that the strong transcriptional response in the lung precedes the peak of viral replication. Surprisingly, the set of down-regulated genes was small and none of these genes displayed strong down-regulation. Responses in the lung-draining lymph nodes were much less prominent than lung responses and are suggestive of NK cell activation. Our data indicate that at time points prior to the peak of viral replication and influx of inflammatory cells, the local lung response, measured at the transcriptional level, has already dampened down. The processes and pathways induced shortly after RSV infection can now be used for the selection of candidate genes for human genetic studies of children with severe RSV infection.

IL-13 genetic polymorphism identifies children with late wheezing after respiratory syncytial virus infection.

BACKGROUND: The nature of wheezing after respiratory syncytial virus lower respiratory tract infection (RSV LRTI) is usually transient. However, some children will develop persistent or late wheezing. OBJECTIVE: We hypothesized that early and late postbronchiolitis wheezing are determined by distinct clinical, immunologic, and genetic variables. METHODS: A cohort of 101 children hospitalized for RSV LRTI was prospectively followed for 6 years. During RSV LRTI, cytokine studies were performed and genetic polymorphisms were determined. Parents performed daily log registration of respiratory symptoms during the first 3 years of follow-up and again at age 6 years during the winter season. RESULTS: Distinctive associations for early and late postbronchiolitis wheezing were found. We previously showed that airflow limitation during RSV LRTI as well as convalescent monocyte IL-10 production are associated with early wheezing. These variables were not associated with late wheezing. On the other hand, atopic family history was not associated with early wheezing, but it was associated with late wheezing. Most importantly, the IL-13 Gln allele was associated with late wheezing (odds ratio 3.27, 95% confidence interval 1.32-8.06), but it was not associated with early wheezing. CONCLUSION: This study revealed distinct clinical, immunologic, and genetic determinants of early and late wheezing after RSV LRTI, indicating distinct pathophysiological mechanisms. We conclude that late wheezing at age 6 years, but not early postbronchiolitis wheezing, is an asthmatic phenomenon and genetically related to a functional IL-13 polymorphism. CLINICAL IMPLICATIONS: After RSV LRTI, wheezing at age 6 years is not related to early postbronchiolitis wheezing and represents a distinct disease entity.

Adipose gene expression response of lean and obese mice to short-term dietary restriction.

Overweight and obesity lead to higher morbidity risks, which are alleviated even by mild weight loss. To gain insight in the molecular effects of weight loss in adipose tissue, we analyzed the effects of short-term dietary restriction (DR) on mice fed a low-fat diet (lean mice) or a high-fat diet (obese mice). Female C57Bl6/J mice on both diets were on DR until an average body weight loss of 20%, which was achieved in 8 to 12 days depending on body weight at the start of DR. Plasma free fatty acids and blood glucose levels decreased significantly on DR. In the (restricted) low-fat diet groups, gene expression analysis using adipose-enriched cDNA microarrays revealed only two transcripts to be significant differentially expressed by DR: up-regulation of malic enzyme (Mod1) and down-regulation of major urinary protein 1 (Mup1). Real-time polymerase chain reaction analysis confirmed these findings and showed, for the high-fat diet groups, an identical expression pattern for Mup1, whereas Mod1 showed an opposed gene expression pattern for the high-fat diet groups. In conclusion, initial weight loss induces transcriptional changes only in a very small number of adipose genes, which also depends on the (restricted) diet used.

Adipose gene expression patterns of weight gain suggest counteracting steroid hormone synthesis.

OBJECTIVE: To identify early molecular changes in weight gain, using analysis of gene expression changes in adipose tissue of mice fed well-defined humanized (Western) high-fat and low-fat (control) diets during a short (3- to 5-week) time interval. RESEARCH METHODS AND PROCEDURES: An adipose-enriched cDNA microarray was constructed and used for the expression analyses of visceral adipose tissues of wildtype young adult C57BL/6J male mice on different diets. RESULTS: Mice on a high-fat diet had significantly higher body weight (at most, 9.6% greater) and adipose tissue weights compared with mice on a control diet. Gene expression analyses revealed 31 transcripts significantly differentially expressed in visceral adipose tissue between the diet groups. Most of these genes were expressed more on the high-fat diet. They mainly encode proteins involved in cellular structure (e.g., myosin, procollagen, vimentin) and lipid metabolism (e.g., leptin, lipoprotein lipase, carbonic anhydrase 3). This increase in gene expression was accompanied by a decrease in oxidative phosphorylation and carbohydrate metabolism (ATP citrate lyase). Importantly, genes belonging to steroid hormone biosynthesis (3beta-hydroxysteroid dehydrogenase-1, cholesterol side-chain cleavage cytochrome P450, and steroid-11beta-hydroxylase) were all expressed less in mice on a high-fat diet. DISCUSSION: A short time period of 3 to 5 weeks of high-fat feeding altered gene expression patterns in visceral adipose tissue in male mice. Gene expression changes indicate initiation of adipose tissue enlargement and the down-regulation of adipose steroid hormone biosynthesis. The latter suggests a mechanism by which initial progression toward weight gain is counteracted.

Combining the transmission disequilibrium test and case-control methodology using generalized logistic regression.

To study the role of genetic factors in the etiology, susceptibility, or severity of disease, several methods are available. In a transmission disequilibrium test, genotypes of cases are compared to those of their parents to explore whether a specific allele, or marker, at a locus of interest appears to be transmitted in excess of what is expected on the basis of Mendelian inheritance. Such apparent excess transmission indicates that cases are being selected for that allele, thereby providing evidence that this allele is a risk factor for disease. In case-control studies, genotypes of cases are compared to those of controls from the same population to identify whether a specific allele is associated with disease. If so, either the allele at this locus or one in linkage disequilibrium with it may be causally related to the etiology of the disease. Here, we discuss the problem of combining a transmission disequilibrium test and a case-control comparison, in order to integrate all available information, and thereby increase statistical power. As the same cases are used in both approaches, the two results are not independent. However, parents of cases can be independently compared to controls. Both the issue of testing for a genetic effect and the estimation of relative risks under the multiplicative model using generalized logistic regression are discussed.

Leptin responsiveness to energy restriction: genetic variation in the leptin receptor gene.

Serum leptin concentrations are an important afferent signal in energy balance homeostasis. It has been speculated that the leptin responsiveness to energy restriction is affected by the functionality of the leptin receptor. The purpose of this analysis was to explore the effect of polymorphisms in the LEPR gene on the acute decline in leptin after 4 days of 65% energy restriction. Leptin concentrations of the study group (n = 44; all men) declined by 2.3 +/- 1.5 micro g/L [-39.4% (95% confidence interval: -43.6 to -34.9)]. Leptin responses did not statistically differ between noncarriers and carriers of three mutant variants of the polymorphisms: Lys109/Lys109 (-41.4%) vs. Arg109/+ (-37.0%) (p = 0.33); Gln223/Gln223 (-41.5%) vs. Arg223/+ (-37.8%) (p = 0.40); Lys656/Lys656 (-39.5%) vs. Asn656/+ (-39.3%) (p = 0.96). No effect of the assessed polymorphisms in the LEPR gene on the acute decline in leptin after energy restriction was observed. Power calculations are provided for future studies on the leptin responsiveness to energy restriction.

Influence of promoter variants of interleukin-10, interleukin-9, and tumor necrosis factor-alpha genes on respiratory syncytial virus bronchiolitis.

Previously, we reported genetic associations between severe respiratory syncytial virus (RSV) bronchiolitis in infants and polymorphisms in the interleukin (IL)-4 and IL-4 receptor alpha (IL-4Ralpha) genes, providing evidence for involvement of T helper type 2 cytokines in the pathogenesis of RSV bronchiolitis. We expanded our studies to polymorphisms in genes encoding IL-9, IL-10, and tumor necrosis factor (TNF)-alpha, using both a transmission/disequilibrium test and a case-control approach. Children homozygous for the IL-10 -592C or -592A allele had a higher risk of hospitalization for RSV bronchiolitis than did heterozygous carriers (odds ratio [OR], 1.73 vs. 2.55; 95% confidence interval [CI], 1.13-2.66 vs. 1.21-5.39). In children hospitalized at < or =6 months of age, a significant association between RSV bronchiolitis and the IL-10 -592C allele was found (OR, 1.61; 95% CI, 1.10-2.35). No significant associations of TNF-alpha and IL-9 polymorphisms with RSV bronchiolitis were observed. We also explored the interactions between different polymorphisms and found an interaction between the IL-4Ralpha Q551R and IL-10 C-592A polymorphisms.

Genetic variation in the leptin receptor gene, leptin, and weight gain in young Dutch adults.

OBJECTIVE: To investigate the association between leptin levels, polymorphisms in the leptin receptor (LEPR) gene, and weight gain. RESEARCH METHODS AND PROCEDURES: From two large prospective cohorts in The Netherlands (n = 17,500), we compared the baseline leptin of 259 subjects who had gained an average of 12.6 kg (range 5.5 to 33 kg) with 277 subjects who kept stable weight (range -2.6 to 3.1 kg) after a mean follow-up of 6.8 years. Three polymorphisms in the LEPR gene (Lys109Arg, Gln223Arg, and Lys656Asn) were determined. RESULTS: Weight gainers had significantly higher baseline leptin levels than those who kept stable weight (odds ratio = 1.27, 95% confidence interval 1.1 to 1.5, per SD increase in log(e)-transformed leptin). Weight gainers with the Arg109 or the Arg223 alleles had higher leptin levels compared with the noncarriers of these alleles. Only among men, the association between leptin and weight gain tended to be stronger among those with an Arg223 allele compared with those without this mutation. DISCUSSION: Relatively high leptin levels predict weight gain, suggesting that leptin resistance plays a role in the development of obesity in the general population. Higher leptin levels for those with a Lys109Arg or Gln223Arg mutation (or a linked other marker) may imply that these subjects have a modified functional leptin receptor. However, the role of these mutations on weight gain is limited.

Association of severe respiratory syncytial virus bronchiolitis with interleukin-4 and interleukin-4 receptor alpha polymorphisms.

The association of variants of genes encoding interleukin (IL)-4 and the IL-4 receptor alpha chain (IL-4Ralpha) with respiratory syncytial virus (RSV) bronchiolitis was examined in hospitalized infants. Polymorphisms in IL-4 (C-590T) and IL-4Ralpha (I50V and Q551R) were genotyped by restriction fragment-length polymorphism analysis. Control subjects included parents of the hospitalized children (for the transmission/disequilibrium test), and a random population sample (for the case-control study). Results were also analyzed in a combination of these 2 tests, using Fisher's method. The IL-4 590T allele was found more frequently among children hospitalized with RSV than expected in the case-control (odds ratio [OR], 1.43; P=.04) and combination (OR, 1.41; P=.02) tests. Among children who were >6 months old when they were hospitalized, compared with the control group or with the <6 months old who were hospitalized for RSV infection, higher frequencies of both the IL-4 590T allele and the IL-4Ralpha R551 allele were found. These results indicate that gain-of-function variants of T helper type 2 cytokine genes may play a role in increasing the severity of RSV disease, which appears more pronounced after the first half-year of life.