Essential role for GABARAP autophagy proteins in interferon-inducible GTPase-mediated host defense.

Mammalian autophagy-related 8 (Atg8) homologs consist of LC3 proteins and GABARAPs, all of which are known to be involved in canonical autophagy. In contrast, the roles of Atg8 homologs in noncanonical autophagic processes are not fully understood. Here we show a unique role of GABARAPs, in particular gamma-aminobutyric acid (GABA)-A-receptor-associated protein-like 2 (Gabarapl2; also known as Gate-16), in interferon-γ (IFN-γ)-mediated antimicrobial responses. Cells that lacked GABARAPs but not LC3 proteins and mice that lacked Gate-16 alone were defective in the IFN-γ-induced clearance of vacuolar pathogens such as Toxoplasma. Gate-16 but not LC3b specifically associated with the small GTPase ADP-ribosylation factor 1 (Arf1) to mediate uniform distribution of interferon-inducible GTPases. The lack of GABARAPs reduced Arf1 activation, which led to formation of interferon-inducible GTPase-containing aggregates and hampered recruitment of interferon-inducible GTPases to vacuolar pathogens. Thus, GABARAPs are uniquely required for antimicrobial host defense through cytosolic distribution of interferon-inducible GTPases.

Age-of-onset information helps identify 76 genetic variants associated with allergic disease.

Risk factors that contribute to inter-individual differences in the age-of-onset of allergic diseases are poorly understood. The aim of this study was to identify genetic risk variants associated with the age at which symptoms of allergic disease first develop, considering information from asthma, hay fever and eczema. Self-reported age-of-onset information was available for 117,130 genotyped individuals of European ancestry from the UK Biobank study. For each individual, we identified the earliest age at which asthma, hay fever and/or eczema was first diagnosed and performed a genome-wide association study (GWAS) of this combined age-of-onset phenotype. We identified 50 variants with a significant independent association (P<3x10-8) with age-of-onset. Forty-five variants had comparable effects on the onset of the three individual diseases and 38 were also associated with allergic disease case-control status in an independent study (n = 222,484). We observed a strong negative genetic correlation between age-of-onset and case-control status of allergic disease (rg = -0.63, P = 4.5x10-61), indicating that cases with early disease onset have a greater burden of allergy risk alleles than those with late disease onset. Subsequently, a multivariate GWAS of age-of-onset and case-control status identified a further 26 associations that were missed by the univariate analyses of age-of-onset or case-control status only. Collectively, of the 76 variants identified, 18 represent novel associations for allergic disease. We identified 81 likely target genes of the 76 associated variants based on information from expression quantitative trait loci (eQTL) and non-synonymous variants, of which we highlight ADAM15, FOSL2, TRIM8, BMPR2, CD200R1, PRKCQ, NOD2, SMAD4, ABCA7 and UBE2L3. Our results support the notion that early and late onset allergic disease have partly distinct genetic architectures, potentially explaining known differences in pathophysiology between individuals.

Filaggrin loss-of-function mutations are associated with persistence of egg and milk allergy.

BACKGROUND: A genetic defect in the epidermal barrier protein filaggrin (FLG) plays a major role in the etiology of eczema and associated allergic airways diseases. However, it is still controversial to what extend loss-of-function (LOF) mutations in FLG contribute to the development and persistence of food allergies. OBJECTIVES: This study tested association of FLG LOF mutations with allergic reactions to diverse foods and investigated their potential effect on the persistence of early food allergies. METHODS: This study recruited 890 children with challenge-proven food allergy for the German Genetics of Food Allergy Study (GOFA). Longitudinal data were available for 684 children. All children were clinically characterized, including their allergic responses to specific foods, and genotyped for the 4 most common LOF mutations in FLG; R501X, 2282del4, R2447X, and S3247X. Associations between FLG mutations and food allergies were analyzed by logistic regression using the German Multicenter Allergy Study cohort as the control population. RESULTS: FLG mutations were associated with allergies to diverse foods including hen's egg (HE), cow's milk (CM), peanut, hazelnut, fish, soy, cashew, walnut, and sesame with similar risk estimates. Effects remained significant after adjusting for the eczema status. Interestingly, FLG mutations increased the risk of a persistent course of HE and CM allergy. CONCLUSIONS: Using the gold standard for food allergy diagnosis, this study demonstrates that FLG LOF mutations confer a risk of any food allergy independent of eczema. These mutations predispose to the persistence of HE and CM allergy and should be considered in the assessment of tolerance development.

Pre-diagnostic C-reactive protein concentrations, CRP genetic variation and mortality among individuals with colorectal cancer in Western European populations.

BACKGROUND: The role of elevated pre-diagnostic C-reactive protein (CRP) concentrations on mortality in individuals with colorectal cancer (CRC) remains unclear. METHODS: We investigated the association between pre-diagnostic high-sensitivity CRP concentrations and CRP genetic variation associated with circulating CRP and CRC-specific and all-cause mortality based on data from 1,235 individuals with CRC within the European Prospective Investigation into Cancer and Nutrition cohort using multivariable-adjusted Cox proportional hazards regression. RESULTS: During a median follow-up of 9.3 years, 455 CRC-specific deaths were recorded, out of 590 deaths from all causes. Pre-diagnostic CRP concentrations were not associated with CRC-specific (hazard ratio, HR highest versus lowest quintile 0.92, 95% confidence interval, CI 0.66, 1.28) or all-cause mortality (HR 0.91, 95% CI 0.68, 1.21). Genetic predisposition to higher CRP (weighted score based on alleles of four CRP SNPs associated with higher circulating CRP) was not significantly associated with CRC-specific mortality (HR per CRP-score unit 0.95, 95% CI 0.86, 1.05) or all-cause mortality (HR 0.98, 95% CI 0.90, 1.07). Among four investigated CRP genetic variants, only SNP rs1205 was significantly associated with CRC-specific (comparing the CT and CC genotypes with TT genotype, HR 0.54, 95% CI 0.35, 0.83 and HR 0.58, 95% CI 0.38, 0.88, respectively) and all-cause mortality (HR 0.58, 95% CI 0.40, 0.85 and 0.64, 95% CI 0.44, 0.92, respectively). CONCLUSIONS: The results of this prospective cohort study do not support a role of pre-diagnostic CRP concentrations on mortality in individuals with CRC. The observed associations with rs1205 deserve further scientific attention.

Protein-coding variants contribute to the risk of atopic dermatitis and skin-specific gene expression.

BACKGROUND: Fifteen percent of atopic dermatitis (AD) liability-scale heritability could be attributed to 31 susceptibility loci identified by using genome-wide association studies, with only 3 of them (IL13, IL-6 receptor [IL6R], and filaggrin [FLG]) resolved to protein-coding variants. OBJECTIVE: We examined whether a significant portion of unexplained AD heritability is further explained by low-frequency and rare variants in the gene-coding sequence. METHODS: We evaluated common, low-frequency, and rare protein-coding variants using exome chip and replication genotype data of 15,574 patients and 377,839 control subjects combined with whole-transcriptome data on lesional, nonlesional, and healthy skin samples of 27 patients and 38 control subjects. RESULTS: An additional 12.56% (SE, 0.74%) of AD heritability is explained by rare protein-coding variation. We identified docking protein 2 (DOK2) and CD200 receptor 1 (CD200R1) as novel genome-wide significant susceptibility genes. Rare coding variants associated with AD are further enriched in 5 genes (IL-4 receptor [IL4R], IL13, Janus kinase 1 [JAK1], JAK2, and tyrosine kinase 2 [TYK2]) of the IL13 pathway, all of which are targets for novel systemic AD therapeutics. Multiomics-based network and RNA sequencing analysis revealed DOK2 as a central hub interacting with, among others, CD200R1, IL6R, and signal transducer and activator of transcription 3 (STAT3). Multitissue gene expression profile analysis for 53 tissue types from the Genotype-Tissue Expression project showed that disease-associated protein-coding variants exert their greatest effect in skin tissues. CONCLUSION: Our discoveries highlight a major role of rare coding variants in AD acting independently of common variants. Further extensive functional studies are required to detect all potential causal variants and to specify the contribution of the novel susceptibility genes DOK2 and CD200R1 to overall disease susceptibility.

Eleven loci with new reproducible genetic associations with allergic disease risk.

BACKGROUND: A recent genome-wide association study (GWAS) identified 99 loci that contain genetic risk variants shared between asthma, hay fever, and eczema. Many more risk loci shared between these common allergic diseases remain to be discovered, which could point to new therapeutic opportunities. OBJECTIVE: We sought to identify novel risk loci shared between asthma, hay fever, and eczema by applying a gene-based test of association to results from a published GWAS that included data from 360,838 subjects. METHODS: We used approximate conditional analysis to adjust the results from the published GWAS for the effects of the top risk variants identified in that study. We then analyzed the adjusted GWAS results with the EUGENE gene-based approach, which combines evidence for association with disease risk across regulatory variants identified in different tissues. Novel gene-based associations were followed up in an independent sample of 233,898 subjects from the UK Biobank study. RESULTS: Of the 19,432 genes tested, 30 had a significant gene-based association at a Bonferroni-corrected P value of 2.5 × 10-6. Of these, 20 were also significantly associated (P < .05/30 = .0016) with disease risk in the replication sample, including 19 that were located in 11 loci not reported to contain allergy risk variants in previous GWASs. Among these were 9 genes with a known function that is directly relevant to allergic disease: FOSL2, VPRBP, IPCEF1, PRR5L, NCF4, APOBR, IL27, ATXN2L, and LAT. For 4 genes (eg, ATXN2L), a genetically determined decrease in gene expression was associated with decreased allergy risk, and therefore drugs that inhibit gene expression or function are predicted to ameliorate disease symptoms. The opposite directional effect was observed for 14 genes, including IL27, a cytokine known to suppress TH2 responses. CONCLUSION: Using a gene-based approach, we identified 11 risk loci for allergic disease that were not reported in previous GWASs. Functional studies that investigate the contribution of the 19 associated genes to the pathophysiology of allergic disease and assess their therapeutic potential are warranted.

Sequence selective photoinduced electron transfer of a pyrene-porphyrin dyad to DNA.

The binding modes of a pyrene-porphyrin dyad, (1-pyrenyl)-tris(N-methyl-p-pyridino)porphyrin (PyTMpyP), to various DNAs (calf thymus DNA (Ct-DNA), poly[d(G-C)2], and poly[d(A-T)2]) have been investigated using circular dichroism and linear dichroism measurements. Based on the polarization spectroscopic results, it can be shown that the pyrenyl and porphryin planes are skewed to a large extent for PyTMPyP in an aqueous environment and in the binding site of poly[d(G-C)2]. In this complex, a photoinduced electron transfer (PET) process between the pyrenyl and porphyrin moieties occurs. On the other hand, PET was not observed in the PyTMPyP-poly[d(A-T)2] complex, whereas the fluorescence intensity of TMPyP was enhanced. The molecular planes of the pyrene and porphyrin moieties are almost parallel in the poly[d(A-T)2] and Ct-DNA adducts. Moreover, the generation of 1O2 species occurs only for the PyTMPyP-Ct-DNA and PyTMPyP-poly[d(A-T)2] complexes. We discuss the photophysical properties of PyTMPyP which are attributed to the binding patterns and the sequence of DNA bases.

RabGDIα is a negative regulator of interferon-γ-inducible GTPase-dependent cell-autonomous immunity to Toxoplasma gondii.

IFN-γ orchestrates cell-autonomous host defense against various intracellular vacuolar pathogens. IFN-γ-inducible GTPases, such as p47 immunity-related GTPases (IRGs) and p65 guanylate-binding proteins (GBPs), are recruited to pathogen-containing vacuoles, which is important for disruption of the vacuoles, culminating in the cell-autonomous clearance. Although the positive regulation for the proper recruitment of IRGs and GBPs to the vacuoles has been elucidated, the suppressive mechanism is unclear. Here, we show that Rab GDP dissociation inhibitor α (RabGDIα), originally identified as a Rab small GTPase inhibitor, is a negative regulator of IFN-γ-inducible GTPases in cell-autonomous immunity to the intracellular pathogen Toxoplasma gondii. Overexpression of RabGDIα, but not of RabGDIß, impaired IFN-γ-dependent reduction of T. gondii numbers. Conversely, RabGDIα deletion in macrophages and fibroblasts enhanced the IFN-γ-induced clearance of T. gondii. Furthermore, upon a high dose of infection by T. gondii, RabGDIα-deficient mice exhibited a decreased parasite burden in the brain and increased resistance in the chronic phase than did control mice. Among members of IRGs and GBPs important for the parasite clearance, Irga6 and Gbp2 alone were more frequently recruited to T. gondii-forming parasitophorous vacuoles in RabGDIα-deficient cells. Notably, Gbp2 positively controlled Irga6 recruitment that was inhibited by direct and specific interactions of RabGDIα with Gbp2 through the lipid-binding pocket. Taken together, our results suggest that RabGDIα inhibits host defense against T. gondii by negatively regulating the Gbp2-Irga6 axis of IFN-γ-dependent cell-autonomous immunity.

Maternal filaggrin mutations increase the risk of atopic dermatitis in children: an effect independent of mutation inheritance.

Epidemiological studies suggest that allergy risk is preferentially transmitted through mothers. This can be due to genomic imprinting, where the phenotype effect of an allele depends on its parental origin, or due to maternal effects reflecting the maternal genome's influence on the child during prenatal development. Loss-of-function mutations in the filaggrin gene (FLG) cause skin barrier deficiency and strongly predispose to atopic dermatitis (AD). We investigated the 4 most prevalent European FLG mutations (c.2282del4, p.R501X, p.R2447X, and p.S3247X) in two samples including 759 and 450 AD families. We used the multinomial and maximum-likelihood approach implemented in the PREMIM/EMIM tool to model parent-of-origin effects. Beyond the known role of FLG inheritance in AD (R1meta-analysis = 2.4, P = 1.0 x 10-36), we observed a strong maternal FLG genotype effect that was consistent in both independent family sets and for all 4 mutations analysed. Overall, children of FLG-carrier mothers had a 1.5-fold increased AD risk (S1 = 1.50, Pmeta-analysis = 8.4 x 10-8). Our data point to two independent and additive effects of FLG mutations: i) carrying a mutation and ii) having a mutation carrier mother. The maternal genotype effect was independent of mutation inheritance and can be seen as a non-genetic transmission of a genetic effect. The FLG maternal effect was observed only when mothers had allergic sensitization (elevated allergen-specific IgE antibody plasma levels), suggesting that FLG mutation-induced systemic immune responses in the mother may influence AD risk in the child. Notably, the maternal effect reported here was stronger than most common genetic risk factors for AD recently identified through genome-wide association studies (GWAS). Our study highlights the power of family-based studies in the identification of new etiological mechanisms and reveals, for the first time, a direct influence of the maternal genotype on the offspring's susceptibility to a common human disease.

Genetic variation in the ADIPOQ gene, adiponectin concentrations and risk of colorectal cancer: a Mendelian Randomization analysis using data from three large cohort studies.

Higher levels of circulating adiponectin have been related to lower risk of colorectal cancer in several prospective cohort studies, but it remains unclear whether this association may be causal. We aimed to improve causal inference in a Mendelian Randomization meta-analysis using nested case-control studies of the European Prospective Investigation into Cancer and Nutrition (EPIC, 623 cases, 623 matched controls), the Health Professionals Follow-up Study (HPFS, 231 cases, 230 controls) and the Nurses' Health Study (NHS, 399 cases, 774 controls) with available data on pre-diagnostic adiponectin concentrations and selected single nucleotide polymorphisms in the ADIPOQ gene. We created an ADIPOQ allele score that explained approximately 3% of the interindividual variation in adiponectin concentrations. The ADIPOQ allele score was not associated with risk of colorectal cancer in logistic regression analyses (pooled OR per score-unit unit 0.97, 95% CI 0.91, 1.04). Genetically determined twofold higher adiponectin was not significantly associated with risk of colorectal cancer using the ADIPOQ allele score as instrumental variable (pooled OR 0.73, 95% CI 0.40, 1.34). In a summary instrumental variable analysis (based on previously published data) with higher statistical power, no association between genetically determined twofold higher adiponectin and risk of colorectal cancer was observed (0.99, 95% CI 0.93, 1.06 in women and 0.94, 95% CI 0.88, 1.01 in men). Thus, our study does not support a causal effect of circulating adiponectin on colorectal cancer risk. Due to the limited genetic determination of adiponectin, larger Mendelian Randomization studies are necessary to clarify whether adiponectin is causally related to lower risk of colorectal cancer.

DNA methylation within melatonin receptor 1A (MTNR1A) mediates paternally transmitted genetic variant effect on asthma plus rhinitis.

BACKGROUND: Asthma and allergic rhinitis (AR) are common allergic comorbidities with a strong genetic component in which epigenetic mechanisms might be involved. OBJECTIVE: We aimed to identify novel risk loci for asthma and AR while accounting for parent-of-origin effect. METHODS: We performed a series of genetic analyses, taking into account the parent-of-origin effect in families ascertained through asthma: (1) genome-wide linkage scan of asthma and AR in 615 European families, (2) association analysis with 1233 single nucleotide polymorphisms (SNPs) covering the significant linkage region in 162 French Epidemiological Study on the Genetics and Environment of Asthma families with replication in 154 Canadian Saguenay-Lac-Saint-Jean asthma study families, and (3) association analysis of disease and significant SNPs with DNA methylation (DNAm) at CpG sites in 40 Saguenay-Lac-Saint-Jean asthma study families. RESULTS: We detected a significant paternal linkage of the 4q35 region to asthma and allergic rhinitis comorbidity (AAR; P = 7.2 × 10(-5)). Association analysis in this region showed strong evidence for the effect of the paternally inherited G allele of rs10009104 on AAR (P = 1.1 × 10(-5), reaching the multiple-testing corrected threshold). This paternally inherited allele was also significantly associated with DNAm levels at the cg02303933 site (P = 1.7 × 10(-4)). Differential DNAm at this site was found to mediate the identified SNP-AAR association. CONCLUSION: By integrating genetic and epigenetic data, we identified that a differentially methylated CpG site within the melatonin receptor 1A (MTNR1A) gene mediates the effect of a paternally transmitted genetic variant on the comorbidity of asthma and AR. This study provides a novel insight into the role of epigenetic mechanisms in patients with allergic respiratory diseases.

Role of mouse and human autophagy proteins in IFN-γ-induced cell-autonomous responses against Toxoplasma gondii.

IFN-γ mediates cellular innate immunity against an intracellular parasite, Toxoplasma gondii, by inducing immunity-related GTPases such as p47 IFN-γ-regulated GTPases (IRGs) and p65 guanylate-binding proteins (GBPs), which also participate in antibacterial responses via autophagy. An essential autophagy protein, Atg5, was previously shown to play a critical role in anti-T. gondii cell-autonomous immunity. However, the involvement of other autophagy proteins remains unknown. In this study, we show that essential autophagy proteins differentially participate in anti-T. gondii cellular immunity by recruiting IFN-γ-inducible GTPases. IFN-γ-induced suppression of T. gondii proliferation and recruitment of an IRG Irgb6 and GBPs are profoundly impaired in Atg7- or Atg16L1-deficient cells. In contrast, cells lacking other essential autophagy proteins, Atg9a and Atg14, are capable of mediating the anti-T. gondii response and recruiting Irgb6 and GBPs to the parasites. Although IFN-γ also stimulates anti-T. gondii cellular immunity in humans, whether this response requires GBPs and human autophagy proteins remains to be seen. To analyze the role of human ATG16L1 and GBPs in IFN-γ-mediated anti-T. gondii responses, human cells lacking ATG16L1 or GBPs were generated by the Cas9/CRISPR genome-editing technique. Although both ATG16L1 and GBPs are dispensable for IFN-γ-induced inhibition of T. gondii proliferation in the human cells, human ATG16L1 is also required for the recruitment of GBPs. Taken together, human ATG16L1 and mouse autophagy components Atg7 and Atg16L1, but not Atg9a and Atg14, participate in the IFN-γ-induced recruitment of the immunity-related GTPases to the intracellular pathogen.

A trans-acting locus regulates an anti-viral expression network and type 1 diabetes risk.

Combined analyses of gene networks and DNA sequence variation can provide new insights into the aetiology of common diseases that may not be apparent from genome-wide association studies alone. Recent advances in rat genomics are facilitating systems-genetics approaches. Here we report the use of integrated genome-wide approaches across seven rat tissues to identify gene networks and the loci underlying their regulation. We defined an interferon regulatory factor 7 (IRF7)-driven inflammatory network (IDIN) enriched for viral response genes, which represents a molecular biomarker for macrophages and which was regulated in multiple tissues by a locus on rat chromosome 15q25. We show that Epstein-Barr virus induced gene 2 (Ebi2, also known as Gpr183), which lies at this locus and controls B lymphocyte migration, is expressed in macrophages and regulates the IDIN. The human orthologous locus on chromosome 13q32 controlled the human equivalent of the IDIN, which was conserved in monocytes. IDIN genes were more likely to associate with susceptibility to type 1 diabetes (T1D)-a macrophage-associated autoimmune disease-than randomly selected immune response genes (P = 8.85 × 10(-6)). The human locus controlling the IDIN was associated with the risk of T1D at single nucleotide polymorphism rs9585056 (P = 7.0 × 10(-10); odds ratio, 1.15), which was one of five single nucleotide polymorphisms in this region associated with EBI2 (GPR183) expression. These data implicate IRF7 network genes and their regulatory locus in the pathogenesis of T1D.

Prediction and prevention of allergic rhinitis: A birth cohort study of 20 years.

BACKGROUND: Allergic rhinitis (AR) is one of the most common chronic diseases, usually starting in the first 2 decades of life. Information on predictors, risk, and protective factors is missing because of a lack of long-term prospective studies. OBJECTIVE: Our aim was to examine early-life environmental and lifestyle determinants for AR up to age 20 years. METHODS: In 1990, the Multicenter Allergy Study included 1314 newborns in 5 German cities. Children were evaluated at 19 time points. A Cox regression model examined the associations between 41 independent early-life factors and onset of AR (as the primary outcome), including sensitization against aeroallergens and the secondary outcomes of nonallergic rhinitis and AR plus asthma. RESULTS: Two hundred ninety subjects had AR within 13,179 person years observed. The risk of AR was higher with a parental history of AR (adjusted hazard ratio [aHR], 2.49; 95% CI, 1.93-3.21), urticaria (aHR, 1.32; 95% CI, 1.00-1.74), or asthma (aHR, 1.29; 95% CI, 0.95-1.75). Early allergic sensitization (aHR, 4.53; 95% CI, 3.25-6.32), eczema within the first 3 years of life (aHR, 1.83; 95% CI, 1.38-2.42), male sex (aHR, 1.28; 95% CI, 1.02-1.61), and birthday in summer or autumn (aHR, 1.26; 95% CI, 1.00-1.58) were independent predictors of AR up to age 20 years. None of the other socioeconomic, environmental, lifestyle, pregnancy, and birth-related factors were associated with AR. CONCLUSION: Only nonmodifiable factors, particularly early allergic sensitization or eczema and parental AR, predicted AR up to age 20 years. No modifiable aspects of early-life environment or lifestyle were identified as targets for primary prevention.

Mutations in the gene encoding the 3'-5' DNA exonuclease TREX1 are associated with systemic lupus erythematosus.

TREX1 acts in concert with the SET complex in granzyme A-mediated apoptosis, and mutations in TREX1 cause Aicardi-Goutières syndrome and familial chilblain lupus. Here, we report monoallelic frameshift or missense mutations and one 3' UTR variant of TREX1 present in 9/417 individuals with systemic lupus erythematosus but absent in 1,712 controls (P = 4.1 x 10(-7)). We demonstrate that two mutant TREX1 alleles alter subcellular targeting. Our findings implicate TREX1 in the pathogenesis of SLE.

Association of CRP genetic variants with blood concentrations of C-reactive protein and colorectal cancer risk.

High blood concentrations of C-reactive protein (CRP) have been associated with elevated risk of colorectal cancer in several prospective studies including the European Prospective Investigation into Cancer and Nutrition (EPIC), but it is unknown whether these observations reflect a causal relationship. We aimed to investigate whether CRP genetic variants associated with lifelong higher CRP concentrations translate into higher colorectal cancer risk. We conducted a prospective nested case-control study within EPIC including 727 cases diagnosed between 1992 and 2003 and 727 matched controls selected according to an incidence-density sampling protocol. Baseline CRP concentrations were measured in plasma samples by a high sensitivity assay. Tagging single nucleotide polymorphisms (SNPs) in the CRP gene (rs1205, rs1800947, rs1130864, rs2808630, rs3093077) were identified via HapMap. The causal effect of CRP on colorectal cancer risk was examined in a Mendelian Randomization approach utilizing multiple CRP genetic variants as instrumental variables. The SNPs rs1205, rs1800947, rs1130864 and rs3093077 were significantly associated with CRP concentrations and were incorporated in a CRP allele score which was associated with 13% higher CRP concentrations per allele count (95% confidence interval 8-19%). Using the CRP-score as instrumental variable, genetically twofold higher CRP concentrations were associated with higher risk of colorectal cancer (odds ratio 1.74, 95% confidence interval 1.06-2.85). Similar observations were made using alternative definitions of instrumental variables. Our findings give support to the hypothesis that elevated circulating CRP may play a direct role in the etiology of colorectal cancer.

Plasma fetuin-A concentration, genetic variation in the AHSG gene and risk of colorectal cancer.

Fetuin-A, also referred to as α2-Heremans-Schmid glycoprotein (AHSG), is a liver protein known to inhibit insulin actions. Hyperinsulinemia is a possible risk factor for colorectal cancer; however, the role of fetuin-A in the development of colorectal cancer is unclear. We investigated the association between circulating fetuin-A and colorectal cancer risk in a nested case-control study within the European Prospective Investigation into Cancer and Nutrition. Fetuin-A concentrations were measured in prediagnostic plasma samples from 1,367 colorectal cancer cases and 1,367 matched controls. In conditional logistic regression models adjusted for potential confounders, the estimated relative risk (95% confidence interval) of colorectal cancer per 40 µg/mL higher fetuin-A concentrations (approximately one standard deviation) was 1.13 (1.02-1.24) overall, 1.21 (1.05-1.39) in men, 1.06 (0.93-1.22) in women, 1.13 (1.00-1.27) for colon cancer and 1.12 (0.94-1.32) for rectal cancer. To improve causal inference in a Mendelian Randomization approach, five tagging single nucleotide polymorphisms of the AHSG gene were genotyped in a subset of 456 case-control pairs. The AHSG allele-score explained 21% of the interindividual variation in plasma fetuin-A concentrations. In instrumental variable analysis, genetically raised fetuin-A was not associated with colorectal cancer risk (relative risk per 40 µg/mL genetically determined higher fetuin-A was 0.98, 95% confidence interval: 0.73-1.33). The findings of our study indicate a modest linear association between fetuin-A concentrations and risk of colorectal cancer but suggest that fetuin-A may not be causally related to colorectal cancer development.

Allergic multimorbidity of asthma, rhinitis and eczema over 20 years in the German birth cohort MAS.

BACKGROUND: The occurrence of allergic multimorbidity (coexistence of asthma, allergic rhinitis and eczema) has not been evaluated longitudinally from early childhood up to adulthood in a population-based study sample. We aimed to determine the prevalence of allergic multimorbidity up to age 20 stratified by parental allergies and sex/gender using extensive prospective follow-up data from two decades of a birth cohort study. METHODS: In 1990, we recruited 1314 healthy newborns from 6 maternity wards across Germany for the population-based MAS birth cohort study. The sample was purposely risk-enriched by increasing the proportion of children at high allergy risk (i.e. at least 2 allergic family members among parents and siblings) from 19% in the source population to 38% in the final sample. The remaining 62% of all MAS children had a low or no allergy risk. Symptoms, medication and doctor's diagnoses of allergic diseases have been assessed using standardized questionnaires including validated ISAAC questions in 19 follow-up assessments up to age 20. Allergic multimorbidity at each time point was defined as the coexistence of at least 2 of the following diseases in one participant: asthma, allergic rhinitis and eczema. RESULTS: Response at age 20 was 72% (n = 942) of all recruited participants. At age 20, 18.5% (95% CI, 15.0-22.5%) of all participants with allergic parents had 2 or 3 concurrent allergies as compared to only 6.3% (95% CI, 4.3-9.0%) of those with non-allergic parents. At this age, allergic multimorbidity was similar in women and men (12.7% (95% CI, 9.7-16.2%) vs. 11.6% (95% CI, 8.9-14.8%)), whereas single allergic diseases were slightly more common in women than men (24.2% (95% CI, 20.2-28.5%) vs. 20.1% (95% CI, 16.6-24.0%)). Asthma occurred more frequently with coexisting allergic rhinitis and/or eczema than as a single entity from pre-puberty to adulthood. CONCLUSION: Having parents with allergies is not only a strong predictor to develop any allergy, but it strongly increases the risk of developing allergic multimorbidity. In males and females alike, coexisting allergies were increasingly common throughout adolescence up to adulthood. Particularly asthma occurred in both sexes more frequently with coexisting allergies than as a single entity.