Intestinal defensin secretion in infancy is associated with the emergence of sensitization and atopic dermatitis

Host-microbiota interactions in the infant gut revealed by daily faecal sample time series

Aim: This study aims to explore the interplay between host immune factors and gut microbiota in human infants in vivo using time-series daily stool samples and identify biomarkers of host-microbe interactions. Methods: 216 faecal samples collected from infants aged 5-6 or 11-12 months were analysed for gut microbiota composition, total bacterial load, and biomarkers of immune function. Results: We identified indications of microbial stimulation of eosinophil cationic protein (ECP), IgA, calprotectin (Cal), intestinal alkaline phosphatase (IAP), and Bactericidal/permeability-increasing protein (BPI) at 6 and 12 months, as well as stimulation of lipocalin 2 (LCN2), lactoferrin (LTF), and alpha-defensin-5 only at 6 months. The associations between biomarker concentrations and bacterial population growth were primarily positive at 6 months and mostly negative at 12 months, suggesting increasing host regulation of the microbiota with age. The exceptions were IAP, which was predictive of declining bacterial populations at both time points, and Cal, whose associations changed from negative at 6 months to positive at 12 months. Conclusion: There is an age-associated development in the correlation pattern between bacterial population growth and the biomarker concentrations, suggesting that host-microbe interactions change during early development. Albumin appeared as a potential marker of gut permeability, while LCN2 seemed to correlate with gut transit time. Mucin degradation appeared to decrease with age. Mucin2 and IAP emerged as potentially important regulators of the bacterial populations in the infant gut. The study demonstrates the utility of biomarker and bacteria profiling from daily stool samples for analysing in vivo associations between the immune system and the gut microbiota and provides evidence of host regulation of the microbiota in infants.

Gut Inflammation Markers, Diet, and Risk of Islet Autoimmunity in Finnish Children - A Nested Case-Control Study

BACKGROUND

Gut dysbiosis and increased intestinal permeability have been reported to precede type 1 diabetes-related autoimmunity. The role of gut inflammation in autoimmunity is not understood.

OBJECTIVES

This study aimed to assess whether gut inflammation markers are associated with risk of islet autoimmunity and whether diet is associated with gut inflammation markers.

METHODS

A nested case-control sample of 75 case children with islet autoimmunity and 88 control children was acquired from the Finnish Type 1 Diabetes Prediction and Prevention cohort. Diet was assessed with 3-d food records, and calprotectin and human β-defensin-2 (HBD-2) were analyzed from stool samples at 6 and 12 mo of age. Conditional logistic regression analysis was used in a matched case-control setting to assess risk of autoimmunity. Analysis of variance, independent samples t test, and a general linear model were used in secondary analyses to test associations of background characteristics and dietary factors with inflammation markers.

RESULTS

In unadjusted analyses, calprotectin was not associated with risk of islet autoimmunity, whereas HBD-2 in the middle (odds ratio [OR]: 3.23; 95% confidence interval [CI]: 1.03, 10.08) or highest tertile (OR: 3.02; 95% CI: 1.05, 8.69) in comparison to the lowest at 12 mo of age showed borderline association (P-trend = 0.063) with higher risk of islet autoimmunity. Excluding children with cow milk allergy in sensitivity analyses strengthened the association of HBD-2 with islet autoimmunity, whereas adjusting for dietary factors and maternal education weakened it. At age 12 mo, higher fat intake was associated with higher HBD-2 (β: 0.219; 95% CI: 0.110, 0.328) and higher intake of dietary fiber (β: -0.294; 95% CI: -0.510, -0.078), magnesium (β: -0.036; 95% CI: -0.059, -0.014), and potassium (β: -0.003; 95% CI: -0.005, -0.001) with lower HBD-2.

CONCLUSIONS

Higher HBD-2 in infancy may be associated with higher risk of islet autoimmunity. Dietary factors play a role in gut inflammatory status.

Increased Intestinal Permeability and Stool Zonulin, Calprotectin and Beta-Defensin-2 Concentrations in Allogenic Hematopoietic Cell Transplantation Recipients

Significant progress has been made in understanding the connection between intestinal barrier function and allogenic hematopoietic cell transplantation (allo-HCT) recipients' outcomes. The purpose of this study was to further evaluate gut barrier permeability and other potential intestinal barrier disruption markers in the allo-HCT setting. Fifty-one patients were enrolled in the study. Intestinal permeability was assessed with the sugar absorption test and faecal concentrations of the zonulin, calprotectin and beta-defensin-2 levels in the peri-transplantation period. Most patients undergoing allo-HCT in our department had a disrupted intestinal barrier at the baseline, which was associated with older age and higher Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI). Regardless of this, we observed a further increase in gut barrier permeability after allo-HCT in most patients. However, there was no association between permeability assay and other markers (zonulin, calprotectin and beta-defensin-2). Patients with acute GVHD had significantly higher median calprotectin concentrations after allo-HCT compared with the patients without this complication. Our findings indicate that gut barrier damage develops prior to allo-HCT with progression after the procedure and precedes further complications, but did not prove other markers to be useful surrogates of intestinal permeability.

Symbiotic microorganisms: prospects for treating atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is a common chronic recurrent inflammatory skin disease. The pathogenesis is unclear but may be related to genetic, immune, and environmental factors and abnormal skin barrier function. Symbiotic microorganisms in the gut and on the skin are associated with AD occurrence.

AREAS COVERED

We discuss the metabolism and distribution of intestinal and skin flora and review their relationship with AD, summarizing the recent applications of intestinal and skin flora in AD treatment, and discussing the prospect of research on these two human microbiota systems and their influence on AD treatment. The PubMed database was searched to identify relevant publications from 1949 to 2020 for the bibliometric analysis of atopic dermatitis and symbiotic microorganisms.

EXPERT OPINION

Many studies have suggested a potential contribution of microbes in the intestine and on the skin to AD. Bacteria living on the skin can aggravate AD by secreting numerous virulence factors. Moreover, the metabolism of intestinal flora can influence AD occurrence and development via the circulatory system. Current evidence suggests that by regulating intestinal and skin flora, AD can be treated and prevented.

Increased fecal human beta-defensin-2 expression in preterm infants is associated with allergic disease development in early childhood

Background

This study aimed to investigate whether fecal human beta-defensins (HBD)-2 and eosinophil cationic protein (ECP) expression in preterm infants are associated with allergic disease development by age 2 years.

Methods

Preterm infants' stool samples were collected at the age of 6 and 12 months postnatally. Information regarding medication exposure histories (antibiotics, antipyretics, probiotics) and physician-diagnosed allergic diseases was obtained using age-specific questionnaires and medical records. We compared the 6-month and 12-month fecal HBD-2 and ECP concentrations between the medication exposure and non-exposure group, respectively, and between children who developed allergic diseases and those who did not by 2 years of age. Univariate and multivariable logistic regression analyses were performed to investigate independent variables related to physician-diagnosed allergic diseases by 2 years of age.

Results

Seventy-four preterm infants (gestational age, 31–36 weeks) were included. Fecal HBD-2 levels were significantly increased at 12 months of age among children who developed allergic diseases compared to those who did not (37.18 ± 11.80 ng/g vs. 8.56 ± 4.33 ng/g, P = 0.011). This association was more apparent among allergic children given antibiotics (50.23 ± 16.15 ng/g vs. 9.75 ± 7.16 ng/g, P = 0.008) or antipyretics (46.12 ± 14.22 ng/g vs. 10.82 ± 6.81 ng/g, P = 0.018) during the first year, whereas among allergic children who were previously not exposed to antibiotics or antipyretics, the differences were not significant. Results of the multivariable logistic regression analysis indicated that HBD-2 concentration in 12-month stools was an independent indicator associated with physician-diagnosed allergic diseases by 2 years of age (adjusted odds ratio: 1.03 [95% confidence interval: 1.00–1.05], P = 0.036). Our data revealed a lack of association between fecal ECP and allergic diseases.

Conclusions

We found that preterm infants who expressed high fecal HBD-2 at 12 months of age were associated with physician-diagnosed allergic diseases by the age of 2 years. Further studies are needed to determine the role of fecal HBD-2 in the development of allergic diseases.

Soluble CD14, α-and β-defensins in breast milk: association with the emergence of allergy in a high-risk population

As innate immunity factors in breast milk (BM) modulate infants' immune responses, we investigated whether soluble CD14 (sCD14) and defensin levels in BM are associated with the emergence of allergy in childhood. The randomly selected group of 260 mother-child pairs belonged to a randomized, double-blind placebo-controlled trial where 1223 mothers with fetuses at high risk for allergy received for the 4 last wk of pregnancy a mixture of probiotics, or placebo; after birth, the child received the treatment for 6 mo. Children were followed for the emergence of sensitization and allergic symptoms for 5 yr. IgE-mediated allergic disorder was diagnosed in 80 children by the age of 5 yr. Levels of sCD14, human neutrophil peptide (HNP) 1-3 and β-defensin 2 (HBD2) in colostrum and in BM 3 mo post-partum were measured with ELISA. BM sCD14 levels decreased from 0 to 3 mo. HNP1-3 and HBD2 were detected in colostrum, but not in BM 3 mo post-partum. High sCD14 levels in BM 3 mo post-partum were associated with children developing an IgE-mediated allergic disorder by the age of 5 yr. BM HNP1-3, HBD2 or sCD14 levels were not associated with probiotics treatment. Our results suggest that sCD14 in BM influences the emergence of allergy in children with atopic heredity.

Developments in the field of allergy in 2012 through the eyes of Clinical & Experimental Allergy

In 2012, we received 683 submissions and published 20 editorials, 38 reviews, 11 letters and 128 original articles. This represents an acceptance rate for original papers in the range of 20%. About 30% of original papers were triaged not to go out to review, either because the editors did not feel they had sufficient priority for publication or because the topic did not feel right for the readers of the journal. We place great emphasis on obtaining sufficient high-quality reviews to make our decisions on publication fair and consistent. Inevitably, however, there is a degree of luck about what gets published and which papers miss out, and we are always happy to receive an appeal on our decisions either at the triage stage or after review. This gives us the opportunity to revisit the decision and revise it or explain in more detail to the authors the basis for the decision. Once again in 2012, we were delighted by the quality of the papers submitted and the breadth and depth of research into allergic disease that it revealed. The pattern of papers submitted was similar in previous years with considerable emphasis on all aspects of asthma and rhinitis. We were particularly pleased with our special issue on severe asthma. Elucidating mechanisms using either animal models or patients has always been a major theme of the journal, and the excellent work in these areas has been summarized by Harissios Vliagoftis with a particularly interesting section on early-life events guiding the development of allergic disease, which understandably continue to be a major theme of research. Magnus Wickman summarized the papers looking at the epidemiology of allergic disease including work from birth cohorts, which are an increasingly rich source of data on risk factors for allergic disease, and two papers on the epidemiology of anaphylaxis. Giovanni Passalacqua discussed the papers in the clinical allergy section of the journal, and Adriano Mari who runs the excellent Allergome website discussed the papers looking at allergens including characterization and the relative usefulness of allergen arrays versus single extracts in diagnosis and management.

Effects of ceftriaxone-induced intestinal dysbacteriosis on dendritic cells of small intestine in mice

Intestinal microflora plays a pivotal role in the development of the innate immune system and is essential in shaping adaptive immunity. Dysbacteriosis of intestinal microflora induces altered immune responses and results in disease susceptibility. Dendritic cells (DCs), the professional antigen-presenting cells, have gained increasing attention because they connect innate and adaptive immunity. They generate both immunity in response to stimulation by pathogenic bacteria and immune tolerance in the presence of commensal bacteria. However, few studies have examined the effects of intestinal dysbacteriosis on DCs. In this study, changes of DCs in the small intestine of mice under the condition of dysbacteriosis induced by ceftriaxone sodium were investigated. It was found that intragastric administration of ceftriaxone sodium caused severe dysteriosis in mice. Compared with controls, numbers of DCs in mice with dysbacteriosis increased significantly (P = 0.0001). However, the maturity and antigen-presenting ability of DCs were greatly reduced. In addition, there was a significant difference in secretion of IL-10 and IL-12 between DCs from mice with dysbacteriosis and controls. To conclude, ceftriaxone-induced intestinal dysbacteriosis strongly affected the numbers and functions of DCs. The present data suggest that intestinal microflora plays an important role in inducing and maintaining the functions of DCs and thus is essential for the connection between innate and adaptive immune responses.

Markers of gut mucosal inflammation and cow's milk specific immunoglobulins in non-IgE cow's milk allergy

Background

Allergy to cow’s milk protein (CMP) may cause gastrointestinal (GI) symptoms in the absence of CMP specific IgE. The immunological mechanisms involved in such disease are not fully understood. Therefore we examined markers of gut mucosal inflammation and the immunoglobulin profiles in children with Gl symptoms suspected of cow’s milk protein allergy (CMPA).

Patients and methods

We prospectively recruited infants and young children (n = 57; median age 8.7 months) with gastrointestinal complaints suspected of CMPA. The diagnosis of CMPA was made using the double-blind, placebo-controlled food challenge. Serum and stool samples were collected during CMP-free diet and after both placebo and active challenges. We analyzed the stool samples for calprotectin, human β-defensin 2 and IgA. In serum, we analyzed the levels of β-lactoglobulin and α-casein specific IgA, and IgG antibodies (total IgG and subclasses IgG1 and IgG4). Control group included children with e.g. dermatological or pulmonary problems, consuming normal diets.

Results

Fecal calprotectin levels were higher in the challenge positive group (n = 18) than in the negative (n = 37), with respective geometric means 55 μg/g [95% confidence interval 38–81] and 29 [24–36] μg/g (p = 0.0039), during cow’s milk free diet. There were no significant inter-group differences in the fecal β-defensin and IgA levels. The CMP specific IgG and IgA were not elevated in patients with CMPA, but the levels of β-lactoglobulin-IgG4 (p = 0.0118) and α-casein-IgG4 (p = 0.0044), and total α-casein-IgG (p = 0.0054) and -IgA (p = 0.0050) in all patient samples (regardless of CMPA diagnosis) were significantly lower compared to the control group using dairy products.

Conclusions

Despite cow’s milk elimination in children intolerant to cow’s milk there might be ongoing low-grade inflammation in the gut mucosa. CMP specific IgG or IgA should not be used to diagnose non-IgE CMPA. The observed frequency of impaired CMP specific total IgA, IgG and IgG4 production in patients following cow’s milk free diet warrants further studies.

Fecal calprotectin, MMP-9, and human beta-defensin-2 levels in pediatric inflammatory bowel disease

PURPOSE

Fecal MMP-9 and human beta-defensin-2 (HBD-2)levels, potential markers of intestinal inflammation, are in sufficiently explored in pediatric inflammatory bowel disease(IBD). The aim was to study fecal MMP-9 and HBD-2 in pediatric IBD to compare their performance to calprotectin and to study whether they would provide additional value in categorizing patients according to their disease subtype.

METHODS

Fecal calprotectin, MMP-9, and HBD-2 levels were measured with ELISA in 110 pediatric patients with IBD(Crohn’s disease, n = 68; ulcerative colitis (UC), n = 27; unclassified, n = 15; median age, 14). To compare the performance of the fecal markers, the area under the receiver operating characteristics curve (±95 % CI) was used. In addition,the best cut-off values of each measure to differentiate IBD patients and controls (n = 27 presenting with diarrhea, abdominal pain, and/or anemia) were derived by maximizing sensitivity and specificity.

RESULTS

Of the fecal markers studied, calprotectin performed best for separation of IBD and non-IBD patients with the are a under curve (AUC) of 0.944 (95 % CI, 0.907 to 0.981). For MMP-9, AUC was 0.837 (95% CI, 0.766 to 0.909), the levels being significantly higher in active IBD and in UC compared with Crohn’s disease (p = 0.0013), but categorization of these patient groups did not take place. HBD-2 did not categorize any of the studied groups.

CONCLUSIONS

Calprotectin was the best fecal marker in pediatric IBD, but MMP-9 showed almost comparable performance in UC, suggesting applicability as a surrogate marker of inflammation. Fecal HBD-2 did not bring information to the disease characteristics of pediatric IBD patients.

Immunomodulatory effects of Escherichia coli ATCC 25922 on allergic airway inflammation in a mouse model

Background

Hygiene hypothesis demonstrates that the lack of microbial exposure would promote the development of allergic airway disease (AAD). Therefore, the gut microbiota, including Escherichia coli (E. coli), would probably offer a potential strategy for AAD.

Objective

To investigate whether E. coli infection is able to suppress the induction of AAD and to elucidate the underlying mechanisms.

Methods

Nonpathogenic E. coli ATCC 25922 was infected by gavage before AAD phase in three patterns: 10⁸ or 10⁶ CFU in neonates or 10⁸ CFU in adults. Then mice were sensitized and challenged with ovalbumin (OVA) to induce allergic inflammation in both the upper and lower airways. Hallmarks of AAD, in terms of eosinophil infiltration and goblet cell metaplasia in subepithelial mucosa, Th2 skewing of the immune response, and levels of T regulate cells (Tregs), were examined by histological analysis, ELISA, and flow cytometry, respectively.

Results

E. coli, especially neonatally infected with an optimal dose, attenuated allergic responses, including a decrease in nasal rubbing and sneezing, a reduction in eosinophil inflammation and goblet cell metaplasia in subepithelial mucosa, decreased serum levels of OVA-specific IgE, and reduced Th2 (IL-4) cytokines. In contrast, this effect came with an increase of Th1 (IFN-r and IL-2) cytokines, and an enhancement of IL-10-secreting Tregs in paratracheal lymph nodes (PTLN).

Conclusion

E. coli suppresses allergic responses in mice, probably via a shift from Th1 to Th2 and/or induction of Tregs. Moreover, this infection is age- and dose-dependent, which may open up novel possibilities for new therapeutic interventions.

Microarray analysis reveals marked intestinal microbiota aberrancy in infants having eczema compared to healthy children in at-risk for atopic disease

BACKGROUND

Deviations in composition and diversity of intestinal microbiota in infancy have been associated with both the development and recurrence of atopic eczema. Thus, we decided to use a deep and global microarray-based method to characterize the diversity and temporal changes of the intestinal microbiota in infancy and to define specific bacterial signatures associated with eczema. Faecal microbiota at 6 and 18 months of age were analysed from 34 infants (15 with eczema and 19 healthy controls) selected from a prospective follow-up study based on the availability of faecal samples. The infants were originally randomized to receive either Lactobacillus rhamnosus GG or placebo.

RESULTS

Children with eczema harboured a more diverse total microbiota than control subjects as assessed by the Simpson's reciprocal diversity index of the microarray profiles. Composition of the microbiota did not differ between study groups at age of 6 months, but was significantly different at age of 18 months as assessed by MCPP (p=0.01). At this age healthy children harboured 3 -fold greater amount of members of the Bacteroidetes (p=0.01). Microbiota of children suffering from eczema had increased abundance of the Clostridium clusters IV and XIVa, which are typically abundant in adults. Probiotic Lactobacillus rhamnosus GG supplementation in early infancy was observed to have minor long-term effects on the microbiota composition.

CONCLUSION

A diverse and adult-type microbiota in early childhood is associated with eczema and it may contribute to the perpetuation of eczema.