Risk of Inflammatory Bowel Disease in Patients With Atopic Dermatitis

An atlas of the shared genetic architecture between atopic and gastrointestinal diseases

Comorbidity among atopic diseases (ADs) and gastrointestinal diseases (GIDs) has been repeatedly demonstrated by epidemiological studies, whereas the shared genetic liability remains largely unknown. Here we establish an atlas of the shared genetic architecture between 10 ADs or related traits and 11 GIDs, comprehensively investigating the comorbidity-associated genomic regions, cell types, genes and genetically predicted causality. Although distinct genetic correlations between AD-GID are observed, including 14 genome-wide and 28 regional correlations, genetic factors of Crohn's disease (CD), ulcerative colitis (UC), celiac disease and asthma subtypes are converged on CD4+ T cells consistently across relevant tissues. Fourteen genes are associated with comorbidities, with three genes are known treatment targets, showing probabilities for drug repurposing. Lower expressions of WDR18 and GPX4 in PBMC CD4+ T cells predict decreased risk of CD and asthma, which could be novel drug targets. MR unveils certain ADs led to higher risk of GIDs or vice versa. Taken together, here we show distinct genetic correlations between AD-GID pairs, but the correlated genomic loci converge on the dysregulation of CD4+ T cells. Inhibiting WDR18 and GPX4 expressions might be candidate therapeutic strategies for CD and asthma. Estimated causality indicates potential guidance for preventing comorbidity.

Exploring Protein Functions of Gut Bacteriome and Mycobiome in Thai Infants Associated with Atopic Dermatitis Through Metaproteomic and Host Interaction Analysis

Atopic dermatitis (AD), a prevalent allergic skin condition in children, has been closely associated with imbalances in the gut microbiome. To investigate these microbial alterations and their functional implications, we investigated protein expression, functions and interactions of the gut bacteriome and mycobiome as well as the human proteome in Thai infants with AD using integrative metaproteomic and host interaction analysis. As we observed, probiotic species, such as Lactobacillus acidophilus and Bacteroides salyersiae, were reduced in abundance in the AD group while key pathogenic bacteria and fungi, such as Streptococcus constellatus and Penicillium chrysogenum, increased in abundance. Additionally, the functional analysis of expressed proteins was enriched in response to stress and DNA repair in the bacteriome and ribosome biogenesis-related processes in the mycobiome of the AD group, potentially associated to increased reactive oxygen species (ROS), intestinal inflammation, fungal growth and microbial dysbiosis. Further, a protein-protein interactions (PPIs) network analysis incorporating the human proteome revealed 10 signature proteins related to stress and immune system processes associated with AD. Our findings propose the interactions of the key species and signature protein functions between the gut microbes and the human host in response to AD in Thai infants. To our knowledge, this study serves as the first framework for monitoring bacteriome-mycobiome-human gut studies associated with AD and other allergic diseases in infants.

Clinical correlates of lifetime and current comorbidity patterns in autoimmune and inflammatory diseases

BACKGROUND

Autoimmune and inflammatory diseases (AIDs) are a heterogeneous group of disorders with diverse etiopathogenic mechanisms. This study explores the potential utility of family history, together with present and past comorbidities, in identifying distinct etiopathogenic subgroups. This approach may facilitate more accurate diagnosis, prognosis and personalized therapy.

METHODS

We performed a multiple correspondence analysis on patients' comorbidities, followed by hierarchical principal component clustering of clinical data from 48 healthy volunteers and 327 patients with at least one of 19 selected AIDs included in the TRANSIMMUNOM cross-sectional study.

RESULTS

We identified three distinct clusters characterized by: 1) the absence of comorbidities, 2) polyautoimmunity, and 3) polyinflammation. These clusters were further distinguished by specific comorbidities and biological parameters. Autoantibodies, allergies, and viral infections characterized the polyautoimmunity cluster, while older age, BMI, depression, cancer, hypertension, periodontal disease, and dyslipidemia characterized the polyinflammation cluster. Rheumatoid arthritis patients were distributed across all three clusters. They had higher DAS28 and prevalence of extra-articular manifestations when belonging to the polyinflammation and polyautoimmunity clusters, and also lower ACPA and RF seropositivity and higher pain scores within the polyinflammation cluster. We developed a model allowing to classify AID patients into comorbidity clusters.

CONCLUSIONS

In this study, we have uncovered three distinct comorbidity profiles among AID patients. These profiles suggest the presence of distinct etiopathogenic mechanisms underlying these subgroups. Validation, longitudinal stability assessment, and exploration of their impact on therapy efficacy are needed for a comprehensive understanding of their potential role in personalized medicine.

Cohort studies on 71 outcomes among people with atopic eczema in UK primary care data

Atopic eczema may be related to multiple subsequent adverse health outcomes. Here, we provide evidence to judge and compare associations between eczema and a comprehensive set of outcomes. We conducted 71 cohort studies (age, sex, general practice-matched) using Clinical Practice Research Datalink Aurum primary care records (1997-2023), comparing up to 3.6 million people with eczema to 16.8 million without. Eczema was associated with subsequent diagnosis of outcomes with adjusted hazard ratios (99% confidence intervals) from Cox regression of up to 4.02(3.95-4.10) for food allergy (rate difference [RD] per 1,000 person-years of 1.5). Besides strong associations with atopic and allergic conditions (e.g., asthma 1.87[1.39-1.82], RD5.4) and skin infections (e.g., molluscum contagiosum 1.81[1.64-1.96], RD1.8), the strongest associations were with Hodgkin's lymphoma (1.85[1.66-2.06], RD0.02), Alopecia Areata (1.77[1.71-1.83], RD0.2), Crohn's disease (1.62[1.54-1.69], RD0.1), Urticaria (1.58[1.57-1.60], RD1.9), Coeliac disease (1.42[1.37-1.47], RD0.1), Ulcerative colitis (1.40[1.34-1.46], RD0.1), Autoimmune liver disease (1.32[1.21-1.43], RD0.01), and Irritable bowel syndrome (1.31[1.29-1.32], RD0.7). Sensitivity analyses revealed the impact of consultation bias or choice of cohort age cut-off on findings. Comparatively large HRs in severe eczema were seen for some liver, gastrointestinal and cardiovascular conditions, osteoporosis, and fractures. Most cancers and neurological conditions were not associated with eczema.

Atopic disease and inflammatory bowel disease: A bidirectional Mendelian randomization study

Observational studies have reported associations between atopic diseases, including allergic rhinitis (AR), asthma, atopic dermatitis (AD), and inflammatory bowel disease (IBD), but the causal relationship remains unknown. We utilized pooled data from genome-wide association studies, qualified instrumental variables were screened according to the 3 hypotheses of MR, and bidirectional causality between atopic diseases and IBD was assessed using 2-sample Mendelian randomization analysis (2SMR). The results of our study suggest that AR increased the risk of Crohn disease (CD) (IVW OR = 1.19, 95% CI = 1.02-1.39, P = .026), ulcerative colitis (UC) (IVW OR = 1.14, 95% CI = 1.01-1.29, P = .031) and overall IBD (IVW OR = 1.15, 95% CI = 1.03-1.28, P = .015); Asthma increased the risk of CD (IVW OR = 7.66, 95% CI = 1.58-37.20, P = .012), UC (IVW OR = 3.81, 95% CI = 1.09-13.32, P = .036) and overall IBD (IVW OR = 5.13, 95% CI = 1.48-17.70, P = .010); AD increased the risk of CD (IVW OR = 1.19, 95% CI = 1.02-1.39, P = .023) and overall IBD (IVW OR = 1.14, 95% CI = 1.03-1.28, P = .015) risk. In reverse causality, only CD increased the risk of AR (IVW OR = 1.02, 95% CI = 1.00-1.05, P = .031). This study shows that atopic diseases of AR and asthma are causally related to IBD and its subtypes, and AD is causally related to IBD (which may be attributed to CD). Of the reverse causality, only CD was causally related to AR.

Atopic Dermatitis in Early Childhood and Risk of Inflammatory Bowel Disease: A Scandinavian Birth Cohort Study

OBJECTIVE

To examine the association between early-life atopic manifestations and later risk of inflammatory bowel disease (IBD), for which prospective data are scarce.

STUDY DESIGN

The population-based All Babies in Southeast Sweden (ABIS) and Norwegian Mother, Father, and Child (MoBa) cohorts follow children from birth (ABIS 1997-1999; MoBa 2000-2009) to the end of 2021. Based on validated questionnaires, parents prospectively reported information on asthma, food-related allergic symptoms, atopic dermatitis, and allergic rhinitis by age 3. IBD was defined by ≥ 2 diagnostic records in the national health registries. Cox regression estimated hazard ratios adjusted (aHRs) for parental IBD, atopy, education level, smoking habits, and national origin. Cohort-specific estimates were pooled using a random-effects model.

RESULTS

We compiled data on 83 311 children (ABIS, n = 9041; MoBa, n = 74 270). In over 1 174 756 person-years of follow-up, 301 participants were diagnosed with IBD. Children with atopic dermatitis at age 3 had an increased risk of IBD (pooled aHR = 1.46 [95% CI = 1.13-1.88]), Crohn's disease (pooled aHR = 1.53 [95%CI = 1.04-2.26]), and ulcerative colitis (pooled aHR = 1.78 [95%CI = 1.15-2.75]). Conversely, any atopic manifestation by age 3 was not associated with IBD (pooled aHR = 1.20 [95%CI = 0.95-1.52]), nor were analyses specifically focused on early-life food-related allergic symptoms, asthma, and allergic rhinitis.

CONCLUSION

While atopic manifestations in early childhood were overall not associated with IBD, children with atopic dermatitis specifically were at increased risk of developing IBD, suggesting shared etiologic traits; these findings might be useful in identifying at-risk individuals for IBD.

Single-Cell Transcriptomic and Targeted Genomic Profiling Adjusted for Inflammation and Therapy Bias Reveal CRTAM and PLCB1 as Novel Hub Genes for Anti-Tumor Necrosis Factor Alpha Therapy Response in Crohn's Disease

BACKGROUND

The lack of reliable biomarkers in response to anti-TNFα biologicals hinders personalized therapy for Crohn's disease (CD) patients. The motivation behind our study is to shift the paradigm of anti-TNFα biomarker discovery toward specific immune cell sub-populations using single-cell RNA sequencing and an innovative approach designed to uncover PBMCs gene expression signals, which may be masked due to the treatment or ongoing inflammation; Methods: The single-cell RNA sequencing was performed on PBMC samples from CD patients either naïve to biological therapy, in remission while on adalimumab, or while on ustekinumab but previously non-responsive to adalimumab. Sieves for stringent downstream gene selection consisted of gene ontology and independent cohort genomic profiling. Replication and meta-analyses were performed using publicly available raw RNA sequencing files of sorted immune cells and an association analysis summary. Machine learning, Mendelian randomization, and oligogenic risk score methods were deployed to validate DEGs highly relevant to anti-TNFα therapy response; Results: This study found PLCB1 in CD4+ T cells and CRTAM in double-negative T cells, which met the stringent statistical thresholds throughout the analyses. An additional assessment proved causal inference of both genes in response to anti-TNFα therapy; Conclusions: This study, jointly with an innovative design, uncovered novel candidate genes in the anti-TNFα response landscape of CD, potentially obscured by therapy or inflammation.