Association of TNF-alpha with severe respiratory syncytial virus infection and bronchial asthma.

Tumor necrosis factor (TNF-)alpha is a proinflammatory cytokine that is important in the innate host defence and thus in the defence of infectious agents. However, in excess it provokes the development of chronic inflammatory diseases. The aim of this study was to test association of TNF with severe RSV bronchiolitis as example of an infectious disease and asthma as representative for a chronic inflammatory condition. The following study populations were genotyped for 4 polymorphisms within TNF-beta (rs909253) and TNF-alpha (rs1799964, rs1799724, rs1800629): 322 asthmatic children, 151 children with severe respiratory syncytial virus (RSV) bronchiolitis and 270 controls. Furthermore, serum TNF-alpha levels were measured by a FlowCytomix Assay. Asthma showed association with two TNF-alpha polymorphisms as well as with TNF haplotypes (p = 0.0050). In contrast, RSV bronchiolitis was associated with TNF haplotypes (p < 0.00001) but not with any single polymorphism. In addition, TNF-alpha serum levels correlated with rs1799724 (p = 0.034). A genetically mediated up-regulation of TNF-alpha expression might provoke a pronounced inflammation of the airways and thus a more severe course of RSV infection as well as the onset of asthma. It remains to be elucidated whether severe RSV bronchiolitis starts TNF-alpha upregulation and is one first step in the direction to asthma later in life, or whether both diseases are independent from each other and supported by TNF-alpha upregulation.

Polymorphisms of toll like receptors in the genetics of severe RSV associated diseases.

Toll like receptors (TLRs) are an essential part of the innate immune response. So far, ten different TLRs were identified in humans. They recognize a wide range of microbial and viral pathogens. Infection by respiratory syncytial virus (RSV) is still a major health problem, about 2% of all children are hospitalised due to RSV bronchiolitis during their first 2 years of live. TLR4 has already been described in association with RSV associated diseases by us and others. Thus we were interested whether other TLRs are also involved in the genetics of severe RSV infection. We genotyped 19 polymorphisms in the autosomal TLRs, these are TLR1, 2, 3, 5, 6, 9 and 10. Association analyses by the Armitage's Trend test revealed weak association of one TLR9 promoter polymorphism with RSV infection (p = 0.013). In addition, association was found with TLR10 haplotypes (p = 0.024). We conclude from our data--that--although we can not rule out a minor involvement of TLR9 polymorphism and TLR10 haplotypes--TLRs other than TLR4 do not play a major role in the genetics of severe RSV associated diseases. Future studies should focus on additional genes of the innate immune response.

Polymorphisms of interferons and their receptors in the genetics of severe RSV-associated diseases.

Because of their important role in the pathophysiology of severe RSV infection, IFNs represent an ideal group of candidate genes for determining RSV disease severity. We studied 14 polymorphisms within 7 genes involved in IFNs signalling. Our study populations consisted of 156 infants with severe RSV infection and 296 healthy control children. None of the genes showed association with severe RSV infection in children. Thus, despite the involvement of different IFNs in the pathophysiology of RSV infection, genetic variants in IFNG and related genes might not alter the risk for the development of severe RSV-associated diseases.

Interleukin (IL)-18 polymorphism 133C/G is associated with severe respiratory syncytial virus infection.

BACKGROUND: Respiratory syncytial virus (RSV) is a major cause of bronchiolitis in infants. During the course of RSV infection, predominant T helper cell (TH) 2 response is associated with disease progression, whereas predominant TH1 reaction provides convalescence. Interleukin (IL)-18 plays an important role in adjusting the TH1/TH2 immune response to viral infections. Thus, we tested the hypothesis that polymorphisms in IL-18 were associated with severe RSV-associated diseases. METHODS: We chose to study the promotor polymorphisms -607A/C (rs1946518) and -137G/C (rs187238), the 2 exon polymorphisms 113T/G (rs360718) and 127C/T (rs360717), and 2 intron polymorphisms 5304A/G (rs795467) and 133G/C (rs360721) within the IL-18 gene. Genotyping was performed on 154 children with severe RSV infection as defined by strict clinical criteria and on 270 controls. Statistical analyses of single polymorphisms made use of the Armitage's trend test, haplotypes were calculated with FASTEHPLUS and FAMHAP. RESULTS: -133G/C showed association with severe RSV infection (P = 0.043). The association was further supported by haplotype analyses with all 6 polymorphisms (P < 0.00001 for association with RSV). CONCLUSIONS: This study indicates possible involvement of IL-18 in the determination of severe RSV-associated diseases. Defining the genetic basis of RSV bronchiolitis might help us in identifying new drug targets for a more specific therapy. In addition, it might enable an early identification of children at risk for RSV bronchiolitis and thus make a selective prevention feasible.

Surfactant protein B polymorphisms are associated with severe respiratory syncytial virus infection, but not with asthma.

BACKGROUND: Surfactant proteins (SP) are important for the innate host defence and essential for a physiological lung function. Several linkage and association studies have investigated the genes coding for different surfactant proteins in the context of pulmonary diseases such as chronic obstructive pulmonary disease or respiratory distress syndrome of preterm infants. In this study we tested whether SP-B was in association with two further pulmonary diseases in children, i. e. severe infections caused by respiratory syncytial virus and bronchial asthma. METHODS: We chose to study five polymorphisms in SP-B: rs2077079 in the promoter region; rs1130866 leading to the amino acid exchange T131I; rs2040349 in intron 8; rs3024801 leading to L176F and rs3024809 resulting in R272H. Statistical analyses made use of the Armitage's trend test for single polymorphisms and FAMHAP and FASTEHPLUS for haplotype analyses. RESULTS: The polymorphisms rs3024801 and rs3024809 were not present in our study populations. The three other polymorphisms were common and in tight linkage disequilibrium with each other. They did not show association with bronchial asthma or severe RSV infection in the analyses of single polymorphisms. However, haplotypes analyses revealed association of SP-B with severe RSV infection (p = 0.034). CONCLUSION: Thus our results indicate a possible involvement of SP-B in the genetic predisposition to severe RSV infections in the German population. In order to determine which of the three polymorphisms constituting the haplotypes is responsible for the association, further case control studies on large populations are necessary. Furthermore, functional analysis need to be conducted.

Impact of IL8 and IL8-receptor alpha polymorphisms on the genetics of bronchial asthma and severe RSV infections.

BACKGROUND: Interleukin 8 (IL8) belongs to the family of chemokines. It mediates the activation and migration of neutrophils from peripheral blood into tissue and hereby plays a pivotal role in the initiation of inflammation. Thus it is important in inflammatory lung diseases like bronchial asthma or severe infections by Respiratory Syncytial Virus (RSV). IL8 acts through binding to the IL8-Receptor alpha (IL8RA). For both genes association with asthma has been described. In addition, IL8 has been found in association with RSV bronchiolitis. The aim of our study was to test both genes for association with asthma and severe RSV infections. In addition we were interested in whether a common genetic background of both diseases exists in regards to these genes. METHODS: We genotyped the two IL8 promotor polymorphisms -251A/T and -781C/T and the three amino acid variants M31R, S276T and R335C in IL8RA on 322 children with asthma, 131 infants with severe RSV associated diseases and 270 controls. Statistical analyses made use of the Armitage's trend test for single polymorphisms and FAMHAP for calculations of haplotypes. RESULTS: We found association of the IL8 polymorphism -781C/T as well as IL8 haplotypes with asthma (p = 0.011 and p = 0.036, respectively). In addition, direct comparison of the asthmatic population with the RSV population revealed significant differences, both for -781C/T alone (p = 0.034) and IL8 haplotypes (p = 0.005). The amino acid variants in IL8RA were evenly distributed in between all three populations. CONCLUSION: We conclude from our data that IL8 might play a role in the genetic predisposition to asthma and that these effects are different or even opposite to the effects on severe RSV diseases. Furthermore, IL8RA is unlikely to play a major role in the genetics of either disease.

[Metatropic dysplasia in a girl with c.1811_1812delinsAT mutation in exon 11 of the TRPV4 gene not previously reported]. / Displasia metatrópica en una niña con mutación c.1811_1812delinsAT en el exón 11 del gen TRPV4 no informada previamente.

Metatropic dysplasia is a skeletal disorder with clinical heterogeneity, characterized by craniofacial dysmorphy including frontal bossing and midface hypoplasia, short trunk,progressive kyphoscoliosis and shortened limbs. The TRPV4 gene is located on 12q24.11, coding a cation channel with nonselective permeability to calcium; it is expressed and involved in many physiological processes through responses to different stimuli. Over 50 mutations in TRPV4 have been described. We present a seven months old girl with heterozygous mutation c.1811_1812delinsAT; p.I604N in intron 11 not previously reported in the TRPV4 gene and with clinical findings compatible with metatropic dysplasia.

Genetic and epidemiological risk factors in the development of bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is the chronic lung disease of preterm infants and still represents a major burden of prematurity. Several clinical risk factors for the onset of the disease are already known. In addition, some candidate genes have recently been identified. We set out to determine clinical as well as genetic risk factors for the development of BPD in the German population. 155 infants born with a gestational age < or = 28 at the tertiary neonatal Centre, Freiburg, were recruited. Clinical data were recorded from hospital charts. 47 children developed moderate or severe BPD. For genetic analyses, 37 polymorphisms within sixteen genes were genotyped on all children. The strongest epidemiological risk factor for BPD was birth weight, followed by low gestational age. Genetic association was detected with single polymorphisms within Tumour necrosis factor alpha, Toll like receptor 10 and vascular endothelial growth factor. The former two genes showed also association with BPD in haplotype analyses. In conclusion, association of BPD was far more convincingly found with a few clinical factors than with genetic polymorphisms. This underscores the genetic complexity of the disease. Furthermore, the identification of predisposing genetic polymorphisms might be hampered by the complex interaction between clinical and genetic factors.

Displasia metatrópica en una niña con mutación c. 1811_1812delinsAT en el exón 11 del gen TRPV4 no informada previamente / Metatropic dysplasia in a girl with c. 1811_1812delinsAT mutation in exon 11 of the TRPV4 gene not previously reported

La displasia metatrópica es una alteración esquelética con heterogeneidad clínica, caracterizada por dismorfias craneofaciales, que incluyen prominencia frontal e hipoplasia medio facial, tronco corto con cifoescoliosis progresiva y acortamiento de las extremidades. El gen TRPV4 se localiza en 12q24.11; codifica a un canal de catión con permeabilidad no selectiva al calcio, el cual se expresa y participa en muchos procesos fisiológicos en respuesta a diversos estímulos. Más de 50 mutaciones en TRPV4 han sido descritas. Se presenta el caso de una niña de 7 meses de edad con mutación heterocigota c.1811_1812delinsAT; p.I604N en el intrón 11 no informada previamente en el gen TRPV4 y con hallazgos clínicos compatibles con displasia metatrópica.

Metatropic dysplasia is a skeletal disorder with clinical heterogeneity, characterized by craniofacial dysmorphy including frontal bossing and midface hypoplasia, short trunk, progressive kyphoscoliosis and shortened limbs. The TRPV4 gene is located on 12q24.11, coding a cation channel with non-selective permeability to calcium; it is expressed and involved in many physiological processes through responses to different stimuli. Over 50 mutations in TRPV4 have been described. We present a seven months old girl with heterozygous mutation c.1811_1812delinsAT; p.I604N in intron 11 not previously reported in the TRPV4 gene and with clinical findings compatible with metatropic dysplasia

Displasia metatrópica en una niña con mutación c.1811_1812delinsAT en el exón 11 del gen TRPV4 no informada previamente / Metatropic dysplasia in a girl with c.1811_1812delinsAT mutation in exon 11 of the TRPV4 gene not previously reported

La displasia metatrópica es una alteración esquelética con heterogeneidad clínica, caracterizada por dismorfias craneofaciales, que incluyen prominencia frontal e hipoplasia medio facial, tronco corto con cifoescoliosis progresiva y acortamiento de las extremidades. El gen TRPV4 se localiza en 12q24.11; codifica a un canal de catión con permeabilidad no selectiva al calcio, el cual se expresa y participa en muchos procesos fisiológicos en respuesta a diversos estímulos. Más de 50 mutaciones en TRPV4 han sido descritas. Se presenta el caso de una niña de 7 meses de edad con mutación heterocigota c.1811_1812delinsAT; p.I604N en el intrón 11 no informada previamente en el gen TRPV4 y con hallazgos clínicos compatibles con displasia metatrópica.(AU)

Displasia metatrópica en una niña con mutación c.1811_1812delinsAT en el exón 11 del gen TRPV4 no informada previamente / Metatropic dysplasia in a girl with c.1811_1812delinsAT mutation in exon 11 of the TRPV4 gene not previously reported

La displasia metatrópica es una alteración esquelética con heterogeneidad clínica, caracterizada por dismorfias craneofaciales, que incluyen prominencia frontal e hipoplasia medio facial, tronco corto con cifoescoliosis progresiva y acortamiento de las extremidades. El gen TRPV4 se localiza en 12q24.11; codifica a un canal de catión con permeabilidad no selectiva al calcio, el cual se expresa y participa en muchos procesos fisiológicos en respuesta a diversos estímulos. Más de 50 mutaciones en TRPV4 han sido descritas. Se presenta el caso de una niña de 7 meses de edad con mutación heterocigota c.1811_1812delinsAT; p.I604N en el intrón 11 no informada previamente en el gen TRPV4 y con hallazgos clínicos compatibles con displasia metatrópica.(AU)

Haplotypes of surfactant protein C are associated with common paediatric lung diseases.

Surfactant protein C is part of the surfactant complex lining up the alveoles and thereby inhibiting collapse of the airways. In addition it is involved in innate immune responses. Rare polymorphisms within surfactant protein C have been linked to sporadic paediatric lung diseases, like proteinosis or interstitial lung diseases. One study in the Finnish population described association of common polymorphisms with neonatal respiratory syndrome. Other common lung diseases have not yet been investigated for association with this gene. The aim of this study was to test surfactant protein C for association with bronchial asthma and with severe respiratory syncytial virus associated diseases in infancy. The two common amino acid variants Asn138Thr and Asn186Ser were genotyped on 322 children with asthma, 131 children with severe respiratory syncytial virus associated diseases and 270 controls. Statistical analyses of single polymorphisms made use of the Armitage's trend test; haplotypes were calculated with FAMHAP and FASTEHPLUS. Polymorphisms were in Hardy-Weinberg equilibrium and in tight linkage equilibrium in all populations. Single polymorphisms showed no association with the diseases, however, surfactant protein C haplotypes were associated with severe respiratory syncytial virus associated diseases (p = 0.013). Furthermore, an inverse haplotype distribution was found between children with asthma and respiratory syncytial virus infection (p = 0.00025). The results of our study might suggest opposing roles of surfactant Protein C in the genetic predisposition for respiratory syncytial virus associated diseases vs. asthma. The causal mechanism for this observation has still to be shown.

Amino acid variants in Surfactant protein D are not associated with bronchial asthma.

Surfactant protein D (SFTPD) belongs to the family of collectins and is part of the innate immune system. Thereby it plays an important role in the defense of various pathogens. Besides it is involved in the development of acute and chronic inflammation of the lung. Levels of SFTPD are elevated in serum and alveolar lavage of asthmatic patients. As SFTPD binds and neutralizes common allergens like house dust mites it is especially important in allergic asthma. Three common amino acid variants have been identified in SFTPD and association of the first variant has been described to severe infection with respiratory syncytial virus. Furthermore the functional impact of all three amino acid variants has been demonstrated. Due to its function SFTPD represents an ideal candidate gene for bronchial asthma and we were interested whether the polymorphisms were in association with asthma in children. The three polymorphisms leading to amino acid exchanges (Met11Thr, Ala160Thr, and Ser270 Thr) were typed by restriction fragment length polymorphisms in 322 asthmatic children and 270 controls. Association analyses were performed by Armitage's trend test. In addition haplotypes were calculated by FASTEHPLUS and FAMHAP. None of the polymorphisms was in association with bronchial asthma. Haplotype analyses revealed four major haplotypes all of which were evenly distributed between the populations. We conclude from our data that functional amino acid variants in SFTPD do not play a major role in the genetic pre-disposition to bronchial asthma in children.

Displasia metatrópica en una niña con mutación c.1811_1812delinsAT en el exón 11 del gen TRPV4 no informada previamente. / [Metatropic dysplasia in a girl with c.1811_1812delinsAT mutation in exon 11 of the TRPV4 gene not previously reported].

Metatropic dysplasia is a skeletal disorder with clinical heterogeneity, characterized by craniofacial dysmorphy including frontal bossing and midface hypoplasia, short trunk,progressive kyphoscoliosis and shortened limbs. The TRPV4 gene is located on 12q24.11, coding a cation channel with nonselective permeability to calcium; it is expressed and involved in many physiological processes through responses to different stimuli. Over 50 mutations in TRPV4 have been described. We present a seven months old girl with heterozygous mutation c.1811_1812delinsAT; p.I604N in intron 11 not previously reported in the TRPV4 gene and with clinical findings compatible with metatropic dysplasia.