Probiotics Function in Preventing Atopic Dermatitis in Children

Multiple primary malignancies and gut microbiome

BACKGROUND

Multiple primary malignancies (MPM) are two or more independent primary malignancies. Recently, the relationship between microbiome and various tumors has been gradually focused on.

OBJECTIVE

To describe the relationship between MPM patients (MPMs) and gut microbiome.

METHODS

A total of 27 MPMs, 30 colorectal cancer patients (CRCs), and 30 healthy individuals were included to obtain metagenomic sequencing data. The knowledge graphs of gut bacteria and enteroviruses were plotted based on metagenomics. Wilcoxon rank-sum test was used to screen the characteristic gut microbiome.

RESULTS

The knowledge graph of gut microbiome in MPM patients was plotted. A total of 26 different gut bacteria, including Dialister, Fecalibacterium and Mediterraneibacter, were found between MPMs and healthy individuals. Twenty gut bacteria, including Parvimonas, Dialister and Mediterraneibacter, were more abundant in MPM complicated by CRC compared with CRCs. Twenty-one different enterovirus, including Triavirus, Punavirus and Lilyvirus, were screened between MPMs and healthy individuals. Triavirus, Punavirus and Lilyvirus were less abundant in MPM than healthy individuals. The abundance of Triavirus, Punavirus and Lilyvirus in CRC patients were also lower than MPM complicated by CRC patients.

CONCLUSION

The knowledge graph of gut microbiome in MPM patients was plotted. It may provide basic data support for future research of MPM.

Clinical, laboratory, and therapeutic differences between immunoglobulin E-mediated and non-immunoglobulin E-mediated cow’s milk protein allergy in children

BACKGROUND

Although breast milk is ideal for newborns, in some cases, it is replaced with cow’s milk, which contains proteins that increase the risk of cow’s milk protein allergy (CMPA).

AIM

To evaluate CMPA prevalence in Bahrain and compare clinical characteristics of children with immunoglobulin E (IgE)- and non-IgE-mediated CMPA.

METHODS

This retrospective cohort study examined children with CMPA diagnosed at the pediatric gastroenterology outpatient clinic of the Salmaniya Medical Complex, Bahrain, between 2014 and 2022, and assessed CMPA prevalence. Clinical presentations, laboratory findings, dietary modifications, and outcomes were compared between children with IgE-mediated and non-IgE-mediated CMPA. Categorical variables were compared using Fisher’s exact test or Pearson’s χ² test, whereas continuous variables were compared using Student’s t-test or the Mann-Whitney U test.

RESULTS

Of 8332 patients, 6022 (72.3%) adhered to their appointment. Of them, 618 (10.3%) were suggested of having CMPA and 595 (96.3%) were included; CMPA prevalence was 2%. Most patients were Bahraini (93.8%) and males (55.3%). Non-IgE-mediated type accounted for 77.3% cases and IgE-mediated type, 22.7%. IgE-mediated CMPA presented more in boys (P = 0.030), and later in life (5.1 months ± 4.5 months vs 4.2 months ± 4.2 months, P = 0.016, 95%CI: 0.08-1.73), had more associated diseases (P < 0.001); and presented with more cutaneous (P = 0.024) and respiratory (P = 0.003) manifestations, severe symptoms [rash/dry skin (P = 0.031), facial swelling/angioedema (P = 0.003), failure to thrive (P = 0.013), apparent life-threatening event (P < 0.001)], and positive physical findings (P = 0.002) than non-IgE-mediated CMPA. Most patients were exclusively fed cow milk formula (50.3%). The amino acid-based formula (AAF) was most prescribed (60.5%) with no difference between the two types (P = 0.173). Although breastfeeding was recommended to 49.6%, only 8.2% were exclusively breastfed. IgE-mediated CMPA was associated with a longer follow-up duration than non-IgE-mediated CMPA (17.3 months ± 14.0 months vs 13.5 months ± 13.4 months, P = 0.005, 95%CI: 1.1-6.3).

CONCLUSION

This study revealed a high CMPA prevalence with clinical differences between both types that can influence treatment. AAF was most prescribed, while breastfeeding with dietary modification is rarely applied.

Biomarkers in Atopic Dermatitis in Children: A Comprehensive Review

Atopic dermatitis (AD) is a chronic inflammatory skin disorder with significant implications for patient quality of life and a well-documented association with the atopic march. Recent advancements in biomarker research have unveiled critical insights into AD pathogenesis, diagnosis, prognosis, and therapeutic monitoring. This comprehensive review evaluates the utility of emerging biomarkers, including cytokines, chemokines, genetic markers, and microbiome-related components, in understanding the disease mechanisms and stratifying patient care. The role of minimally invasive diagnostic techniques, such as tape stripping and RNA monitoring, is highlighted, offering innovative approaches to pediatric populations. Furthermore, this review explores the biomarkers that predict disease progression, therapeutic response, and comorbidities, including food allergies and asthma. Personalized treatment strategies based on endotype-specific biomarkers are discussed as a future direction for improving clinical outcomes. Despite promising findings, the integration of biomarkers into routine practice necessitates further validation through large-scale studies. This work underscores the transformative potential of biomarker-driven approaches in enhancing the management of AD in children and its associated conditions.

Saccharomyces boulardii (CNCM I-745) ameliorates Ovalbumin-induced atopic dermatitis by modulating the NF-κB signaling in skin and colon

Atopic dermatitis (AD) is a long-lasting allergic disorder characterized by itching, redness, swelling, dry skin, scaling, inflammation, and tissue damage. The exact cause of AD is still unknown. Steroid medications are frequently utilized in treating AD, but their prolonged use can result in complications. Multiple studies suggest probiotics may regulate the immune system, boost immune functionality, or reduce overactive immune responses. The current study investigated the anti-inflammatory, antioxidant, and immunomodulatory role of Saccharomyces boulardii in Ovalbumin (OVA)-induced AD in a murine model. Balb/c mice were sensitized and challenged with OVA to induce AD-like lesions. S. boulardii 1 × 109 CFU/ml/day/mice was orally administrated either as a pretreatment (administered 7 days before OVA induction and continued till day 28) or concurrent treatment (administered from day 1 and continued till day 28). Dexamethasone (5 mg/kg/day) was used as a standard treatment. S. boulardii alleviated the macroscopic and behavioral changes. Blood inflammatory cells were significantly reduced. Serum IgE levels were decreased. Oxidative stress and histopathological changes (epidermal/dermal thickness, inflammatory cells, collagen deposition) in skin tissue were improved. Similarly, the colon's antioxidant capacity and histological architecture were also maintained. Expression of proinflammatory cytokines like TNF-⍺ and IL-1β were significantly reduced in skin and colon tissue. The probiotic S. boulardii under study reduced inflammation by downregulating NF-κB signaling in both skin and colon tissue. This study provides a basis for a possible gut-skin axis, which can be targeted to relieve AD symptoms.

Effect of Supplementation with a Specific Probiotic (Bifidobacterium bifidum PRL2010) in Pregnancy for the Prevention of Atopic Dermatitis in Children: Preliminary Results of a Randomized Trial

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by the appearance of recurrent eczematous lesions and intense itching. The World Allergy Organization (WAO) suggested the administration of probiotics in pregnant women at high risk of allergies in their children.

OBJECTIVES

Our study aims to evaluate the role of administering the Bifidobacterium bifidum strain PRL2010 during pregnancy and breastfeeding in preventing and/or reducing the severity of AD manifestations in children.

METHODS

It is a monocentric, randomized, double-blind, placebo-controlled trial with probiotic/placebo administration since the 36th week of gestation to mothers with atopy or a family history of atopy; the effects were evaluated over the first 12 months of the children's lives.

RESULTS

No severe adverse effects due to probiotic intake were reported in our cohort. Although proportionally fewer children with AD were in the probiotic group, the statistical analysis showed no significant differences between the probiotic and placebo groups. However, infants who developed the most severe forms of AD in the probiotic group showed a better clinical course during follow-up compared to those in the placebo group.

CONCLUSIONS

In conclusion, administering the probiotic Bifidobacterium bifidum strain PRL2010 during pregnancy and breastfeeding is safe and potentially beneficial; further large-scale studies may confirm its usefulness in improving the clinical manifestation of AD in children with a family history of atopy.

Gut Dysbiosis and Adult Atopic Dermatitis: A Systematic Review

Background/Objectives: Research on the relationship between gut microbiota (GM) and atopic dermatitis (AD) has seen a growing interest in recent years. The aim of this systematic review was to determine whether differences exist between the GM of adults with AD and that of healthy adults (gut dysbiosis). Methods: We conducted a systematic review based on the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). The search was performed using PubMed, EMBASE, and Web of Science. Observational and interventional studies were analyzed. Results: Although the studies showed heterogeneous results, some distinguishing characteristics were found in the intestinal microbial composition of adults with dermatitis. Even though no significant differences in diversity were found between healthy and affected adults, certain microorganisms, such as Bacteroidales, Enterobacteriaceae, and Clostridium (perfringens), were more characteristic of the fecal microbiota in adults with AD. Healthy individuals exhibited lower abundances of aerobic bacteria and higher abundances of short-chain fatty acid-producing species and polyamines. Clinical trials showed that the consumption of probiotics (Bifidobacterium and/or Lactobacillus), fecal microbiota transplants, and balneotherapy modified the fecal microbiota composition of participants and were associated with significant improvements in disease management. Conclusions: In anticipation of forthcoming clinical trials, it is essential to conduct meta-analyses that comprehensively evaluate the effectiveness and safety of interventions designed to modify intestinal flora in the context of AD. Preliminary evidence suggests that certain interventions may enhance adult AD management.

Atopic dermatitis: new insights into a common condition

Atopic dermatitis is one of the most common conditions managed in the community world-wide. Atopic dermatitis is under intense scrutiny by academic researchers, not to mention drug companies, enabling regular research in the area. Dermatologists have a growing appreciation of the complex causes of this common condition.

Role of inflammatory cytokines and the gut microbiome in vascular dementia: insights from Mendelian randomization analysis

Background

Both inflammatory cytokines and the gut microbiome are susceptibility factors for vascular dementia (VaD). The trends in the overall changes in the dynamics of inflammatory cytokines and in the composition of the gut microbiome are influenced by a variety of factors, making it difficult to fully explain the different effects of both on the different subtypes of VaD. Therefore, this Mendelian randomization (MR) study identified the inflammatory cytokines and gut microbiome members that influence the risk of developing VaD and their causal effects, and investigated whether inflammatory cytokines are gut microbiome mediators affecting VaD.

Methods

We obtained pooled genome-wide association study (GWAS) data for 196 gut microbiota and 41 inflammatory cytokines and used GWAS data for six VaD subtypes, namely, VaD (mixed), VaD (multiple infarctions), VaD (other), VaD (subcortical), VaD (sudden onset), and VaD (undefined). We used the inverse-variance weighted (IVW) method as the primary MR analysis method. We conducted sensitivity analyses and reverse MR analyses to examine reverse causal associations, enhancing the reliability and stability of the conclusions. Finally, we used multivariable MR (MVMR) analysis to assess the direct causal effects of inflammatory cytokines and the gut microbiome on the risk of VaD, and performed mediation MR analysis to explore whether inflammatory factors were potential mediators.

Results

Our two-sample MR study revealed relationships between the risk of six VaD subtypes and inflammatory cytokines and the gut microbiota: 7 inflammatory cytokines and 14 gut microbiota constituents were positively correlated with increased VaD subtype risk, while 2 inflammatory cytokines and 11 gut microbiota constituents were negatively correlated with decreased VaD subtype risk. After Bonferroni correction, interleukin-18 was correlated with an increased risk of VaD (multiple infarctions); macrophage migration inhibitory factor was correlated with an increased risk of VaD (sudden onset); interleukin-4 was correlated with a decreased risk of VaD (other); Ruminiclostridium 6 and Bacillales were positively and negatively correlated with the risk of VaD (undefined), respectively; Negativicutes and Selenomonadales were correlated with a decreased risk of VaD (mixed); and Melainabacteria was correlated with an increased risk of VaD (multiple infarctions). Sensitivity analyses revealed no multilevel effects or heterogeneity and no inverse causality between VaD and inflammatory cytokines or the gut microbiota. The MVMR results further confirmed that the causal effects of Negativicutes, Selenomonadales, and Melainabacteria on VaD remain significant. Mediation MR analysis showed that inflammatory cytokines were not potential mediators.

Conclusion

This study helps us to better understand the pathological mechanisms of VaD and suggests the potential value of targeting increases or decreases in inflammatory cytokines and gut microbiome members for VaD prevention and intervention.

Delphi Consensus Statement on the Role of Probiotics in the Treatment of Atopic Dermatitis

Background Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by intense itching and recurrent eczematous lesions. Important factors in the etiopathogenesis of AD include genetic predisposition, epidermal barrier dysfunction, immune dysregulation, and gut and skin dysbiosis. Probiotics could be a potential preventive strategy for allergies including AD through immune system modulation as well as enhancement of the epithelial barrier integrity. To further understand the role of probiotics in the management of AD, a Knowledge, Attitude, and Practices (KAP) survey was conducted. Materials and methods A steering committee comprising nine experts formulated consensus recommendations on the role of probiotics in the management of AD and associated flare-ups through the use of the Knowledge, Attitude, and Practices questionnaire while analyzing literature reviews and responses from a national panel consisting of 175 members. The evidence strength and quality were evaluated based on the Agency for Healthcare Research and Quality (AHRQ) criteria. The acceptance of expert opinions as recommendations was considered upon receiving an endorsement from ≥70% of the panelists, as indicated by a Likert scale. Results The national panel emphasized that the improvement in nutritional status, immunomodulatory properties, and beneficial effects on the gastrointestinal (GI) tract and skin support the use of probiotics in AD. The panel agreed that probiotics should be a part of the complementary therapy in the management of AD and associated flare-ups. Mostly, a probiotics supplementation duration of eight to 12 weeks is preferred by dermatologists. Probiotics, when used as an adjuvant therapy, may serve as a strategy to reduce steroid usage or maintenance therapy in high-risk cases with flares. Conclusion A Delphi-mediated KAP response provides a real-life approach to the use of probiotics in the management of AD. It suggests that probiotics could be useful as an adjuvant therapy in the management of AD and associated flare-ups when used along with traditional treatment.

Dietary Intervention during Weaning and Development of Food Allergy: What Is the State of the Art?

Food allergy (FA) affects approximately 6-8% of children worldwide causing a significant impact on the quality of life of children and their families. In past years, the possible role of weaning in the development of FA has been studied. According to recent studies, this is still controversial and influenced by several factors, such as the type of food, the age at food introduction and family history. In this narrative review, we aimed to collect the most recent evidence about weaning and its role in FA development, organizing the gathered data based on both the type of study and the food. As shown in most of the studies included in this review, early food introduction did not show a potential protective role against FA development, and we conclude that further evidence is needed from future clinical trials.

The influence of modern living conditions on the human microbiome and potential therapeutic opportunities for allergy prevention

Modern living conditions and the recent surge in global urbanization have transformed the human microbiome. This transformation is believed to be a significant factor in the recent spike of common chronic inflammatory diseases like asthma and allergies worldwide, evident in both developed and developing nations. Immigrants from less developed regions who settle in highly urbanized and affluent areas present an ideal demographic for research. Investigating immigrant populations can yield valuable insights, particularly when studying microbiome changes that occur as individuals transition from areas with low asthma prevalence to regions with a high prevalence of the condition. The application of prebiotics and probiotics as potential treatments for asthma and allergies faces challenges. This is due to the complex interplay of numerous factors that contribute to their aetiology. Exploring the interaction between the human microbiome and potential epigenetic changes in specific populations, such as immigrants adapting to new, urbanized environments, may offer crucial insights. Such research could underscore the role of prebiotics and probiotics in preventing allergic conditions. Recognizing the changes in the human microbiome in the context of a Western/modern environment might be essential in addressing the increasing prevalence of allergic diseases. Persistent research in this domain is pivotal for devising effective interventions such as dietary supplementation with prebiotics and probiotics.

Current insights on gut microbiome and chronic urticaria: progress in the pathogenesis and opportunities for novel therapeutic approaches

Chronic urticaria (CU) is a prevalent skin disorder greatly impacting the patients' life quality, in which immune dysregulation mediated by gut microbiome plays a significant role. Several studies have found the gut dysbiosis exists in patients with CU. In addition, infection may also be one of the causes of CU. The primary treatment currently used for CU is the second-generation non-sedating H1-antihistamines (nsAH). However, there are some limitations in current therapies. Based on the latest evidence, this review provides an updated overview of how the gut dysbiosis influences CU development, explores potential therapeutic approaches based on the gut microbiota and summarizes the interaction between gut microbiota and current treatment.

Molecular Mechanism and Clinical Effects of Probiotics in the Management of Cow's Milk Protein Allergy

Cow's milk protein allergy (CMPA) is the most common food allergy (FA) in infancy, affecting approximately 2% of children under 4 years of age. According to recent studies, the increasing prevalence of FAs can be associated with changes in composition and function of gut microbiota or "dysbiosis". Gut microbiota regulation, mediated by probiotics, may modulate the systemic inflammatory and immune responses, influencing the development of allergies, with possible clinical benefits. This narrative review collects the actual evidence of probiotics' efficacy in the management of pediatric CMPA, with a specific focus on the molecular mechanisms of action. Most studies included in this review have shown a beneficial effect of probiotics in CMPA patients, especially in terms of achieving tolerance and improving symptoms.

Single-Strain Probiotic Lactobacilli for the Treatment of Atopic Dermatitis in Children: A Systematic Review and Meta-Analysis

Probiotics are known for their positive effects on the gut microbiota. There is growing evidence that the infant gut and skin colonization have a role in the development of the immune system, which may be helpful in the prevention and treatment of atopic dermatitis. This systematic review focused on evaluating the effect of single-strain probiotic lactobacilli consumption on treating children's atopic dermatitis. Seventeen randomized placebo-controlled trials with the primary outcome of the Scoring Atopic Dermatitis (SCORAD) index were included in the systematic review. Clinical trials using single-strain lactobacilli were included. The search was conducted until October 2022 using PubMed, ScienceDirect, Web of Science, Cochrane library and manual searches. The Joanna Briggs Institute appraisal tool was used to assess the quality of the included studies. Meta-analyses and sub meta-analyses were performed using Cochrane Collaboration methodology. Due to different methods of reporting the SCORAD index, only 14 clinical trials with 1124 children were included in the meta-analysis (574 in the single-strain probiotic lactobacilli group and 550 in the placebo group) and showed that single-strain probiotic lactobacilli statistically significantly reduced the SCORAD index compared to the placebo in children with atopic dermatitis (mean difference [MD]: -4.50; 95% confidence interval [CI]: -7.50 to -1.49; Z = 2.93; p = 0.003; heterogeneity I² = 90%). The subgroup meta-analysis showed that strains of Limosilactobacillus fermentum were significantly more effective than strains of Lactiplantibacillus plantarum, Lacticaseibacillus paracasei or Lacticaseibacillus rhamnosus. A longer treatment time and younger treatment age statistically significantly reduced symptoms of atopic dermatitis. The result of this systematic review and meta-analysis shows that certain single-strain probiotic lactobacilli are more successful than others in reducing atopic dermatitis severity in children. Therefore, careful consideration to strain selection, treatment time and the age of the treated patients are important factors in enhancing the effectiveness of reducing atopic dermatitis in children when choosing probiotic single-strain lactobacilli.

Pathogenesis and therapy of radiation enteritis with gut microbiota

Radiotherapy is widely used in clinic due to its good effect for cancer treatment. But radiotherapy of malignant tumors in the abdomen and pelvis is easy to cause radiation enteritis complications. Gastrointestinal tract contains numerous microbes, most of which are mutualistic relationship with the host. Abdominal radiation results in gut microbiota dysbiosis. Microbial therapy can directly target gut microbiota to reverse microbiota dysbiosis, hence relieving intestinal inflammation. In this review, we mainly summarized pathogenesis and novel therapy of the radiation-induced intestinal injury with gut microbiota dysbiosis and envision the opportunities and challenges of radiation enteritis therapy.

Fecal microbiota transplantation affects the recovery of AD-skin lesions and enhances gut microbiota homeostasis

BACKGROUND

Accumulating evidence has shown that gut microbiota plays a key role in the progression of atopic dermatitis (AD). Fecal microbiota transplantation (FMT), as an effective method to restore gut microbiota homeostasis, has been successfully applied for treating many inflammatory diseases. However, the therapeutic effect of FMT on AD remains unclear. The following study examined the effect and mechanism of FMT on AD-skin lesions in an AD mouse model.

METHODS

In this study, we exposed the shaved back skin of BALB/c mice to calcipotriol (MC903) to induce AD model. Mice were then treated with FMT, which was performed with gut microbiota from healthy mice. The gut microbiota of treated mice was tracked by 16S rRNA gene sequencing. Mice skin tissues were examined by histopathology and inflammatory cytokines change in serum by ELISA.

RESULTS

FMT had a faster trend on the reversion of the increases in skin epidermal layer thicknesses and suppressed some of the representative inflammatory cytokines. The gut microbial community in the natural recovery process varied significantly in the FMT group at day 7 (ANOSIM P = 0.0229, r = 0.2593). Notably, FMT had a long-lasting and beneficial impact on the gut microbial compositions of AD mice by increasing the ratio of Firmicutes to Bacteroidetes and the amount of butyric-producing bacteria (BPB), including Erysipelotrichaceae, Lactobacillaceae, and Eubacteriacea. Furthermore, the relative abundances of gut microbiota-mediated functional pathways involved in the cell growth and death, amino acid, energy, lipid, and carbohydrate metabolisms, and immune system increased after FMT treatment.

CONCLUSION

FMT modulated the gut microbiota homeostasis and affected the recovery from AD-related inflammations, suggesting that it could be used as a treatment strategy for AD patients in the clinic.

Probiotics and Prebiotics: Any Role in Menopause-Related Diseases?

PURPOSE OF REVIEW

The aim of this review is to provide an overview of the menopause-related changes in microbiota and their role in the pathogenesis of menopause-related diseases. In addition, evidence on probiotic supplementation as a therapeutic strategy is discussed.

RECENT FINDINGS

The human microbiota is a complex community that lives in a mutualism relationship with the host. Menopause is associated with dysbiosis, and these changes in the composition of microbiota in different sites (gut, vaginal, and oral microbiota) might play a role in the pathogenesis of menopause-related diseases (i.e., osteoporosis, breast cancer, endometrial hyperplasia, periodontitis, and cardiometabolic diseases). The present review highlights the pivotal role of microbiota in postmenopausal women health, in particular it (a) may increase intestinal calcium absorption thus preventing osteoporosis, (b) is associated with reduced risk of breast cancer and type 1 endometrial hyperplasia, (c) reduces gingival inflammation and menopausal periodontitis, and (d) beneficially affects multiple cardiometabolic risk factors (i.e., obesity, inflammation, and blood glucose and lipid metabolism). However, whether oral probiotic supplementation might be used for the treatment of menopause-related dysbiosis requires further clarification.

How an Immune-Factor-Based Formulation of Micro-Immunotherapy Could Interfere with the Physiological Processes Involved in the Atopic March

Allergic diseases consist of improper inflammatory reactions to antigens and are currently an important healthcare concern, especially considering their increasing worldwide development in recent decades. The "atopic march" defines the paradigm of allergic diseases occurring in chronological order and displaying specific spatial manifestations, as they usually start as atopic dermatitis (AD) and food allergies during infancy and progressively evolve into allergic asthma (AA) and allergic rhinitis (AR) or rhino-conjunctivitis in childhood. Many immune cell subtypes and inflammatory factors are involved in these hypersensitivity reactions. In particular, the T helpers 2 (Th2) subset, through its cytokine signatures made of interleukins (ILs), such as IL-4, IL-5, IL-10, and IL-13, as well as mast cells and their related histamine pathways, contribute greatly to the perpetuation and evolution of the atopic march. By providing low doses (LD) and ultra-low doses (ULD) of ILs and immune factors to the body, micro-immunotherapy (MI) constitutes an interesting therapeutic strategy for the management of the atopic march and its symptoms. One of the aims of this review is to shed light on the current concept of the atopic march and the underlying immune reactions occurring during the IgE-mediated responses. Moreover, the different classes of traditional and innovative treatments employed in allergic diseases will also be discussed, with a special emphasis on the potential benefits of the MI medicine 2LALERG^® formulation in this context.

The causality between intestinal flora and allergic diseases: Insights from a bi-directional two-sample Mendelian randomization analysis

Background

Growing evidence shows a significant association between intestinal flora and allergic diseases, specifically atopic dermatitis (AD), allergic rhinitis (AR), and allergic asthma (AA). However, the causality has not yet been clarified.

Objective

We conducted a bidirectional two-sample Mendelian randomization (TSMR) analysis to study the causal relationships between intestinal flora classification and AD, AR, or AA.

Materials and methods

We obtained summary data of intestinal flora, AD, AR, and AA from a genome-wide association research. The inverse-variance weighted method is the primary method for analyzing causality in the TSMR analysis. Several sensitivity analyses were conducted to examine the stability of TSMR results. Reverse TSMR analysis was also performed to assess whether there was a reverse causality.

Results

A total of 7 bacterial taxa associated with AD, AR, and AA were identified by the current TSMR analysis. Specifically, the genus Dialister(P=0.034)and genus Prevotella(P=0.047)were associated with a higher risk of AD, whereas class Coriobacteriia (P=0.034) and its child taxon, order Coriobacteriales (P=0.034) and family Coriobacteriaceae (P=0.034), all had a protective effect on AR. In addition, the family Victivallaceae (P=0.019) was identified as a risk factor for AR. We also noticed a positive association between the genus Holdemanella (P=0.046) and AA. The reverse TSMR analysis didn't suggest any evidence of reverse causality from allergic diseases to the intestinal flora.

Conclusion

We confirmed the causal relationship between intestinal flora and allergic diseases and provided an innovative perspective for research on allergic diseases: targeted regulation of dysregulation of specific bacterial taxa to prevent and treat AD, AR, and AA.

High baseline prevalence of atopic comorbidities and medication use in children treated with allergy immunotherapy in the REAl-world effeCtiveness in allergy immunoTherapy (REACT) study

Background

Respiratory allergy, commonly manifesting as allergic rhinitis (AR) and asthma, is a chronic progressive disease that frequently starts in childhood. Allergy immunotherapy (AIT) is the only causal treatment for respiratory allergy with the potential to modify the underlying cause of allergy and, ultimately, prevent disease progression. This analysis aimed to determine if AIT is received sufficiently early to halt the progression of allergic disease, by characterizing the burden and progression of disease in children prior to AIT initiation in real-life clinical practice.

Methods

The REAl-world effeCtiveness in allergy immunoTherapy (REACT) study was a large retrospective cohort study using German claims data between 2007 and 2017. Characteristics of two pre-defined AIT age cohorts from the REACT study - children (aged <18 years) and adults (aged ≥18 years) - were evaluated during the 1-year period before the first AIT prescription. For comparison, a control group of all subjects with a confirmed diagnosis of AR and without prescriptions for AIT was included. Burden of disease was assessed using diagnostic codes for atopic comorbidities [e.g., atopic dermatitis (AD), asthma, and acute allergic conjunctivitis] and non-atopic comorbidities (e.g., migraine, headache); medication use, recorded as prescriptions for symptom-relieving AR medication and reliever/controller medication for asthma, was also assessed. Data were analyzed descriptively, using summary statistics.

Results

Both children (n = 11,036) and adults (n = 30,037) showed a higher prevalence of atopic comorbidities and a greater drug burden prior to AIT initiation compared to AR patients not treated with AIT (n = 1,003,332). In the two age-specific AIT cohorts, children consistently showed the highest prevalence of atopic comorbidities compared to adults (AIT children, AIT adults - asthma: 41.4%, 34.5%; AD: 19.9%, 10.2%; acute allergic conjunctivitis: 13.6%, 10.2%). Generally, prescriptions per year for symptom-relieving AR and asthma treatments were also higher for children initiating AIT vs. adults (AIT children, AIT adults - AR prescriptions per subject: 1.72, 0.73; asthma prescriptions per subject: 1.42, 0.79).

Conclusions

Children with AR who are offered AIT in real-life show considerable disease burden prior to initiation. As AIT may alleviate the burden and halt the progression of allergic disease, considering AIT earlier in the disease course may be warranted.