Probiotics and prebiotics: clinical effects in allergic disease

The antiviral effects and underlying mechanisms of probiotics on viral infections

In public health emergencies, viral diseases like influenza and COVID-19 have become a major concern. One of the proposed responses to this concern is the use of probiotics. Probiotics have a potent role in arming our bodies to combat viral infections. They affect the innate and adaptive immune systems in various ways. Accumulating studies has shown that probiotics can reduce the possibility of infection or the duration of respiratory symptoms by modulating the functions of the immune system. This review aims to summarize the impacts of probiotics on respiratory viral infections and their potential antiviral mechanisms. Therefore, we herein discussed probiotics in relation to lung immunity, distinct types of respiratory viral infections (VRIs), including influenza, rhinoviruses, respiratory syncytial virus, and upper respiratory viral infections, and lastly, probiotics and their effects on COVID-19. However, more studies are needed to explore the antiviral mechanisms of probiotics.

Oral administration of Lactobacillus delbrueckii UFV-H2b20 protects mice against Aspergillus fumigatus lung infection

INTRODUCTION

Probiotics provide therapeutic benefits not only in the gut but also other mucosal organs, including the lungs.

OBJECTIVE AND DESIGN

To evaluate the effects of the probiotic strain L. delbrueckii UFV-H2b20 oral administration in an experimental murine model of A. fumigatus pulmonary infection. BALB/c mice were associated with L. delbrueckii and infected with Aspergillus fumigatus and compared with non-associated group.

METHODS

We investigated survival, respiratory mechanics, histopathology, colony forming units, cytokines in bronchoalveolar lavage, IgA in feces, efferocytosis, production of reactive oxygen species and the cell population in the mesenteric lymph nodes.

RESULTS

L. delbrueckii induces tolerogenic dendritic cells, IL-10+macrophages and FoxP3+regulatory T cells in mesenteric lymph nodes and increased IgA levels in feces; after infection with A. fumigatus, increased survival and decreased fungal burden. There was decreased lung vascular permeability without changes in the leukocyte profile. There was enhanced neutrophilic response and increased macrophage efferocytosis. L. delbrueckii-treated mice displayed more of FoxP3+Treg cells, TGF-β and IL-10 levels in lungs, and concomitant decreased IL-1β, IL-17 A, and CXCL1 production.

CONCLUSION

Uur results indicate that L. delbrueckii UFV H2b20 ingestion improves immune responses, controlling pulmonary A. fumigatus infection. L. delbrueckii seems to play a role in pathogenesis control by promoting immune regulation.

Recent advances in improving intranasal allergen-specific immunotherapy; focus on delivery systems and adjuvants

Allergen-specific Immunotherapy (AIT) is the main therapeutic strategy to control and treat allergic disorders. Intranasal Immunotherapy (INIT) was introduced as a needle-free, noninvasive, and efficient approach among various routes of allergen administration. Since direct exposure of nasal mucosa to allergen extracts could induce local and systemic reactions, recent studies focus on establishing novel formulations using various delivery systems and adjuvants to improve INIT efficacy. This review categorizes and describes natural and synthetic micro/nanoparticles such as chitosan, PLGA, liposome, exosome, and nano-emulation droplets used as delivery systems or immunomodulatory and immune-regulatory agents. Also, multiple microbial agents, including probiotics, mycobacterial and viral components, TLR ligands, and biologic agents, i.e., antibody fragments, recombinant cytokines, vitamin A, and pulsed dendritic cells (DCs), are other platforms that are discussed. In addition, future perspectives and proposed strategies to help INIT were provided.

A Meta-Analysis of Probiotics for the Treatment of Allergic Airway Diseases in Children and Adolescents

BACKGROUND

Allergic airway disease is a chronic airway allergic inflammatory disease including allergic rhinitis (AR) and allergic asthma which is common in children and adolescents. Recently the probiotics has been becoming a supplementary or alternative therapy to allergic diseases, however the effect of them has not been clearly established.

OBJECTIVE

The purpose of the present meta-analysis was to evaluate the effectiveness of probiotics on allergic airway disease including AR and allergic asthma in children and adolescents.

METHODS

We performed a comprehensive search on PubMed, Cochrane Library, EMBASE for relevant publications from 1 Jan 2000 to 1 July 2021. Physical examinations, Pediatric Rhinoconjunctivitis Quality of Life Questionnaires (PRQLQs), Total Nasal Symptom Score (TNSS), Nasal or Eye Symptom Score (NSS or ESS), serum allergen-specific IgE, and eosinophil were used as evaluating indicators for AR and allergic asthma in children and adolescents. The meta-analysis was performed using Review Manager (RevMan, Version 5.3).

RESULTS

15 randomized controlled trials (RCTs) with a total of 1388 participants were included for the meta-analysis. Among them, 729 patients treated with probiotics served as the probiotics group, and 659 patients with placebo as control group. Significantly greater reduction in PRQLQs from baseline to endpoint (SMD = -2.57, 95% CI [ - 4.66, -0.48] P < 0.01), NSS (SMD = -1.43, 95% CI [ - 1.63, - 1.23], P < 0.01) and ESS (total MD = -1.67, 95% CI [ - 1.79, - 1.55], P < 0.01) were observed in probiotics group compared to control group. Probiotics have no significant effect to serum IgE and eosinophils (P > 0.01).

CONCLUSION

The results of this meta-analysis indicated that probiotics treatment may reduce PRQLQs, NSS, ESS in patients with allergic airway disease. More research involving the mechanism of probiotics are needed to clarify the role of probiotics in AR and allergic asthma in children and adolescents.

Current possibilities and future perspectives for improving efficacy of allergen-specific sublingual immunotherapy

Allergen-specific sublingual immunotherapy (SLIT), a safe and efficient route for treating type I hypersensitivity disorders, requires high doses of allergens. SLIT is generally performed without adjuvants and delivery systems. Therefore, allergen formulation with appropriate presentation platforms results in improved allergen availability, targeting the immune cells, inducing regulatory immune responses, and enhancing immunotherapy's efficacy while decreasing the dose of the allergen. In this review, we discuss the adjuvants and delivery systems that have been applied as allergen-presentation platforms for SLIT. These adjuvants include TLRs ligands, 1α, 25-dihydroxy vitamin D3, galectin-9, probiotic and bacterial components that provoke allergen-specific helper type-1 T lymphocytes (TH1), and regulatory T cells (Tregs). Another approach is encapsulation or adsorption of the allergens into a particulate vector system to facilitate allergen capture by tolerogenic dendritic cells. Also, we proposed strategies to increasing the efficacy of SLIT via new immunopotentiators and carrier systems in the future.

Building Robust Assemblages of Bacteria in the Human Gut in Early Life

The neonatal body provides a range of potential habitats, such as the gut, for microbes. These sites eventually harbor microbial communities (microbiotas). A "complete" (adult) gut microbiota is not acquired by the neonate immediately after birth. Rather, the exclusive, milk-based nutrition of the infant encourages the assemblage of a gut microbiota of low diversity, usually dominated by bifidobacterial species. The maternal fecal microbiota is an important source of bacterial species that colonize the gut of infants, at least in the short-term. However, development of the microbiota is influenced by the use of human milk (breast feeding), infant formula, preterm delivery of infants, caesarean delivery, antibiotic administration, family details and other environmental factors. Following the introduction of weaning (complementary) foods, the gut microbiota develops in complexity due to the availability of a diversity of plant glycans in fruits and vegetables. These glycans provide growth substrates for the bacterial families (such as members of the Ruminococcaceae and Lachnospiraceae) that, in due course, will dominate the gut microbiota of the adult. Although current data are often fragmentary and observational, it can be concluded that the nutrition that a child receives in early life is likely to impinge not only on the development of the microbiota at that time but also on the subsequent lifelong, functional relationships between the microbiota and the human host. The purpose of this review, therefore, is to discuss the importance of promoting the assemblage of functionally robust gut microbiotas at appropriate times in early life.

Food Allergy: Catering for the Needs of the Clinician

The practice of food allergy (FA) for clinicians has boomed, with a dramatic rise in the number of patients and families seeking care and with many advances on several fronts. The practice itself sometimes is evidence-based science and sometimes an art of pattern and phenotype recognition. This article examines the tools for diagnosis and management and therapy options available to physicians providing care for patients with FA. The article touches on pressing needs of clinicians and highlights the rapid and important movements in national and international support and advances that will have a positive impact on the field of FA.

Probiotics as a Possible Strategy for the Prevention and Treatment of Allergies. A Narrative Review

Allergies are an increasing global public health concern, especially for children and people living in urban environments. Allergies impair the quality of life of those who suffer from them, and for this reason, alternatives for the treatment of allergic diseases or reduction in their symptoms are being sought. The main objective of this study was to compile the studies carried out on probiotics as a possible therapy for allergies. The most studied allergies on which probiotics have been shown to have a beneficial effect are rhinitis, asthma, and atopic dermatitis. Most studies have studied the administration of Lactobacillus and Bifidobacterium spp. in children and have shown beneficial effects, such as a reduction in hyperreactivity and inflammation caused by allergens and a decrease in cytokine release, among other beneficial effects. In the case of children, no clear beneficial effects were found in several studies, and the potential risk from the use of some opportunistic bacteria, such as probiotics, seems controversial. In the studies that reported beneficial results, these effects were found to make allergy symptoms less aggressive, thus reducing morbidity in allergy sufferers. The different effects of the same probiotic bacteria on different patients seem to reinforce the idea that the efficacy of probiotics is dependent on the microbial species or strain, its derived metabolites and byproducts, and the gut microbiota eubiosis of the patient. This study is relevant in the context of allergic diseases, as it provides a broader understanding of new alternatives for the treatment of allergies, both in children, who are the main sufferers, and adults, showing that probiotics, in some cases, reduce the symptoms and severity of such diseases.

Dietary factors during pregnancy and atopic outcomes in childhood: A systematic review from the European Academy of Allergy and Clinical Immunology

RATIONALE

Allergic diseases are an increasing public health concern, and early life environment is critical to immune development. Maternal diet during pregnancy has been linked to offspring allergy risk. In turn, maternal diet is a potentially modifiable factor, which could be targeted as an allergy prevention strategy. In this systematic review, we focused on non-allergen-specific modifying factors of the maternal diet in pregnancy on allergy outcomes in their offspring.

METHODS

We undertook a systematic review of studies investigating the association between maternal diet during pregnancy and allergic outcomes (asthma/wheeze, hay fever/allergic rhinitis/seasonal allergies, eczema/atopic dermatitis (AD), food allergies, and allergic sensitization) in offspring. Studies evaluating the effect of food allergen intake were excluded. We searched three bibliographic databases (MEDLINE, EMBASE, and Web of Science) through February 26, 2019. Evidence was critically appraised using modified versions of the Cochrane Collaboration Risk of Bias tool for intervention trials and the National Institute for Clinical Excellence methodological checklist for cohort and case-control studies and meta-analysis performed from RCTs.

RESULTS

We identified 95 papers: 17 RCTs and 78 observational (case-control, cross-sectional, and cohort) studies. Observational studies varied in design and dietary intakes and often had contradictory findings. Based on our meta-analysis, RCTs showed that vitamin D supplementation (OR: 0.72; 95% CI: 0.56-0.92) is associated with a reduced risk of wheeze/asthma. A positive trend for omega-3 fatty acids was observed for asthma/wheeze, but this did not reach statistical significance (OR: 0.70; 95% CI: 0.45-1.08). Omega-3 supplementation was also associated with a non-significant decreased risk of allergic rhinitis (OR: 0.76; 95% CI: 0.56-1.04). Neither vitamin D nor omega-3 fatty acids were associated with an altered risk of AD or food allergy.

CONCLUSIONS

Prenatal supplementation with vitamin D may have beneficial effects for prevention of asthma. Additional nutritional factors seem to be required for modulating the risk of skin and gastrointestinal outcomes. We found no consistent evidence regarding other dietary factors, perhaps due to differences in study design and host features that were not considered. While confirmatory studies are required, there is also a need for performing RCTs beyond single nutrients/foods.

Gut Microbiome Modulation for Preventing and Treating Pediatric Food Allergies

The increasing prevalence and severity of pediatric food allergies (FA) demands innovative preventive and therapeutic strategies. Emerging evidence suggests a pivotal role for the gut microbiome in modulating susceptibility to FA. Studies have demonstrated that alteration of gut microbiome could precede FA, and that particular microbial community structures early in life could influence also the disease course. The identification of gut microbiome features in pediatric FA patients is driving new prevention and treatment approaches. This review is focused on the potential role of the gut microbiome as a target for FA prevention and treatment.

Prebiotics in the Infant Microbiome: The Past, Present, and Future

The latest definition of a prebiotic is "a substrate that is selectively utilized by host microorganisms conferring a health benefit"; it now includes non-food elements and is applicable to extra-intestinal tissues. Prebiotics are recognized as a promising tool in the promotion of general health and in the prevention and treatment of numerous juvenile diseases. Prebiotics are considered an immunoactive agent, with the potential for long-lasting effects extending past active administration of the prebiotic. Because of its extremely low risk of serious adverse effects, ease of administration, and strong potential for influencing the composition and function of the microbiota in the gut and beyond, the beneficial clinical applications of prebiotics are expanding. Prebiotics are the third largest component of human breast milk. Preparations including galactooligosaccharides (GOS), fructooligosaccharides (FOS), 2'-fucosyllactose, lacto-N-neo-tetraose are examples of commonly used and studied products for supplementation in baby formula. In particular, the GOS/FOS combination is the most studied. Maintaining a healthy microbiome is essential to promote homeostasis of the gut and other organs. With more than 1,000 different microbial species in the gut, it is likely more feasible to modify the gut microbiota through the use of certain prebiotic mixtures rather than supplementing with a particular probiotic strain. In this review, we discuss the latest clinical evidence regarding prebiotics and its role in gut immunity, allergy, infections, inflammation, and functional gastrointestinal disorders.

Postnatal probiotics and allergic disease in very preterm infants: Sub-study to the ProPrems randomized trial

BACKGROUND

Probiotic supplementation to mothers and/or their term-born infants has been suggested to prevent allergic disease, in particular eczema; however, no studies have investigated probiotics for prevention of allergic diseases in very preterm infants. We evaluated the effect of a postnatal probiotic combination on development of allergic diseases in very preterm infants.

METHODS

This sub-study was an a priori secondary outcome of the ProPrems multi-center, double-blind, placebo-controlled randomized trial (ANZCTR:12607000144415). ProPrems randomized 1099 very preterm infants to receive a probiotic combination or placebo from soon after birth until discharge from hospital or term corrected age (CA), whichever was earlier. Allergic disease (eczema, atopic eczema, food allergy, wheeze, atopic sensitization) was assessed in a subgroup of ProPrems infants (n = 281) as close to 12 months CA as possible by questionnaire, clinical examination, and skin prick tests to common allergens.

RESULTS

There was no difference in eczema incidence between the probiotic and placebo groups (35[30%] of 118 infants vs 37[27%] of 137 infants, respectively, absolute difference 2.65%, 95% CI -8.45 to 13.75). Similarly, the incidence of atopic eczema (6[5%] of 118 vs 3[2%] of 137), food allergy (4[3%] of 124 vs 2[1%] of 154), wheeze (39[31%] of 127 vs 45[29%] of 154), and atopic sensitization (14[13%] of 106 vs 13[11%] of 123) were similar between the probiotic and placebo groups.

CONCLUSION

This study found no effect of postnatal administration of a probiotic combination on the incidence of allergic diseases or atopic sensitization in the first 2 years of life in children born very preterm. Evidence that probiotics are effective for prevention of allergic disease in premature infants remains lacking; adequately powered randomized controlled trials evaluating probiotic supplementation for allergy prevention in very preterm infants are needed.

Adjuvant Probiotics and the Intestinal Microbiome: Enhancing Vaccines and Immunotherapy Outcomes

Immune defence against pathogenic agents comprises the basic premise for the administration of vaccines. Vaccinations have hence prevented millions of infectious illnesses, hospitalizations and mortality. Acquired immunity comprises antibody and cell mediated responses and is characterized by its specificity and memory. Along a similar congruent yet diverse mode of disease prevention, the human host has negotiated from in utero and at birth with the intestinal commensal bacterial cohort to maintain local homeostasis in order to achieve immunological tolerance in the new born. The advent of the Human Microbiome Project has redefined an appreciation of the interactions between the host and bacteria in the intestines from one of a collection of toxic waste to one of a symbiotic existence. Probiotics comprise bacterial genera thought to provide a health benefit to the host. The intestinal microbiota has profound effects on local and extra-intestinal end organ physiology. As such, we further posit that the adjuvant administration of dedicated probiotic formulations can encourage the intestinal commensal cohort to beneficially participate in the intestinal microbiome-intestinal epithelia-innate-cell mediated immunity axes and cell mediated cellular immunity with vaccines aimed at preventing infectious diseases whilst conserving immunological tolerance. The strength of evidence for the positive effect of probiotic administration on acquired immune responses has come from various studies with viral and bacterial vaccines. We posit that the introduction early of probiotics may provide significant beneficial immune outcomes in neonates prior to commencing a vaccination schedule or in elderly adults prior to the administration of vaccinations against influenza viruses.

The maternal microbiome during pregnancy and allergic disease in the offspring

There is substantial epidemiological and mechanistic evidence that the increase in allergic disease and asthma in many parts of the world in part relates to changes in microbial exposures and diet acting via the composition and metabolic products of the intestinal microbiome. The majority of research in this field has focused on the gut microbiome during infancy, but it is increasingly clear that the maternal microbiome during pregnancy also has a key role in preventing an allergy-prone immune phenotype in the offspring. The mechanisms by which the maternal microbiome influences the developing fetal immune system include alignment between the maternal and infant regulatory immune status and transplacental passage of microbial metabolites and IgG. Interplay between microbial stimulatory factors such as lipopolysaccharides and regulatory factors such as short-chain fatty acids may also influence on fetal immune development. However, our understanding of these pathways is at an early stage and further mechanistic studies are needed. There are also no data from human studies relating the composition and metabolic activity of the maternal microbiome during pregnancy to the offspring's immune status at birth and risk of allergic disease. Improved knowledge of these pathways may inform novel strategies for tackling the increase in allergic disorders in the modern world.

Impact of a novel synbiotic supplementation during gestation and lactation on immune responses in the Swiss albino mice offspring

BACKGROUND

Prebiotics from various regularly consumed cereals and novel substrates are currently being utilised as functional foods. The aim of this study was to determine the effect of synbiotic, formulated with prebiotic extracted from natural resources like green gram (Vigna radiata) along with probiotic Lactobacillus rhamnosus GG (LGG) in modulating immune responses in the offspring when supplemented during gestation and lactation.

RESULTS

Synbiotic supplementation was effective in improving cell mediated immunity and humoral immunity among F0 dams. Among F1 pups (F1 Syn + and F1 Syn-), synbiotic supplementation showed significantly heightened (P < 0.05) splenocyte proliferation, increased interleukin-10, interferon gamma and interleukin-17 responses, leucocyte phagocytic ability and increased secretory-immunoglobulin A. However, four-fold increase in IgG titres to Hepatitis-B vaccine was observed only in those mice that were supplemented with synbiotic postweaning (F1 Syn+).

CONCLUSION

Synbiotic supplementation to pregnant dams affected the offspring's cellular and mucosal immunity favorably. However, IgG response to Hepatitis-B vaccine was influenced positively only when the supplementation was extended to the offsprings in the post weaning period. © 2016 Society of Chemical Industry.

The influence of dietary immunomodulatory factors on development of food allergy in children

In the last few years many studies have been conducted on the role of dietary and environmental factors in the prevention of allergic diseases among children. Many studies have shown that the diet of pregnant women and children in their early postnatal life, rich in antioxidants, vitamin D, and fatty acids is beneficial as it reduces the risk of allergy in their future life. Moreover, there are many reports about the main role of gut microbiota and probiotics in the allergy prevention, what can indicate new ways of procedures in allergic diseases.

A programme of research to set priorities and reduce uncertainties for the prevention and treatment of skin disease

Background

Skin diseases are very common and can have a large impact on the quality of life of patients and caregivers. This programme addressed four diseases: (1) eczema, (2) vitiligo, (3) squamous cell skin cancer (SCC) and (4) pyoderma gangrenosum (PG).

Objective

To set priorities and reduce uncertainties for the treatment and prevention of skin disease in our four chosen diseases.

Design

Mixed methods including eight systematic reviews, three prioritisation exercises, two pilot randomised controlled trials (RCTs), three feasibility studies, two core outcome initiatives, four funding proposals for national RCTs and one completed national RCT.

Setting

Secondary care, primary care and the general population.

Participants

Patients (and their caregivers) with eczema, vitiligo, SCC and PG, plus health-care professionals with an interest in skin disease.

Interventions

Our three intervention studies included (1) barrier enhancement using emollients from birth to prevent eczema (pilot RCT); (2) handheld narrowband ultraviolet light B therapy for treating vitiligo (pilot RCT); and (3) oral ciclosporin (Neoral®, Novartis Pharmaceuticals) compared with oral prednisolone for managing PG (pragmatic national RCT).

Results

Systematic reviews included two overarching systematic reviews of RCTs of treatments for eczema and vitiligo, an umbrella review of systematic reviews of interventions for the prevention of eczema, two reviews of treatments for SCC (one included RCTs and the second included observational studies), and three reviews of outcome measures and outcome reporting. Three prioritisation partnership exercises identified 26 priority areas for future research in eczema, vitiligo and SCC. Two international consensus initiatives identified four core domains for future eczema trials and seven core domains for vitiligo trials. Two pilot RCTs and three feasibility studies critically informed development of four trial proposals for external funding, three of which are now funded and one is pending consideration by funders. Our pragmatic RCT tested the two commonly used systemic treatments for PG (prednisolone vs. ciclosporin) and found no difference in their clinical effectiveness or cost-effectiveness. Both drugs showed limited benefit. Only half of the participants’ ulcers had healed by 6 months. For those with healed ulcers, recurrence was common (30%). Different side effect profiles were noted for each drug, which can inform clinical decisions on an individual patient basis. Three researchers were trained to PhD level and a dermatology patient panel was established to ensure patient involvement in all aspects of the programme.

Conclusions

Findings from this programme of work have already informed clinical guidelines and patient information resources. Feasibility studies have ensured that large national pragmatic trials will now be conducted on important areas of treatment uncertainty that address the needs of patients and the NHS. There is scope for considerable improvement in terms of trial design, conduct and reporting for RCTs of skin disease, which can be improved through wider collaboration, registration of trial protocols and complete reporting and international consensus over core outcome sets. Three national trials have now been funded as a result of this work. Two international initiatives to establish how best to measure the core outcome domains for eczema and vitiligo are ongoing.

Trial registration

Current Controlled Trials Barrier Enhancement for Eczema Prevention (BEEP) (ISRCTN84854178 and NCT01142999), Study of Treatments fOr Pyoderma GAngrenosum Patients (STOP GAP) (ISRCTN35898459) and Hand Held NB-UVB for Early or Focal Vitiligo at Home (HI-Light Pilot Trial) (NCT01478945).

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 4, No. 18. See the NIHR Journals Library website for further project information.

Investigating the Effect of Different Treatments with Lactic Acid Bacteria on the Fate of Listeria monocytogenes and Staphylococcus aureus Infection in Galleria mellonella Larvae

The use of Galleria mellonella as a model host to elucidate microbial pathogenesis and search for novel drugs and therapies has been well appreciated over the past years. However, the effect of microorganisms with functional appeal in the specific host remains scarce. The present study investigates the effect of treatment with selected lactic acid bacteria (LAB) with probiotic potential, as potential protective agents by using live or heat-killed cells at 6 and 24 h prior to infection with Listeria monocytogenes and Staphylococcus aureus or as potential therapeutic agents by using cell-free supernatants (CFS) after infection with the same pathogens. The employed LAB strains were Lactobacillus pentosus B281 and Lactobacillus plantarum B282 (isolated from table olive fermentations) along with Lactobacillus rhamnosus GG (inhabitant of human intestinal tract). Kaplan-Meier survival curves were plotted while the pathogen's persistence in the larval hemolymph was determined by microbiological analysis. It was observed that the time (6 or 24 h) and type (live or heat-killed cells) of challenge period with LAB prior to infection greatly affected the survival of infected larvae. The highest decrease of L. monocytogenes population in the hemolymph was observed in groups challenged for 6 h with heat-killed cells by an average of 1.8 log units compared to non challenged larvae for strains B281 (p 0.0322), B282 (p 0.0325), and LGG (p 0.0356). In the case of S. aureus infection, the population of the pathogen decreased in the hemolymph by 1 log units at 8 h post infection in the groups challenged for 6 h with heat-killed cells of strains B281 (p 0.0161) and B282 (p 0.0096) and by 1.8 log units in groups challenged with heat-killed cells of LGG strain (p 0.0175). Further use of CFS of each LAB strain did not result in any significant prolonged survival but interestingly it resulted in pronounced decrease of L. monocytogenes in the hemolymph at 24 h and 48 h after infection by more than 1 log unit (p < 0.05) depending on the strain. The results of the present work support the broader use of G. mellonella larvae as a low cost in vivo tool for screening for probiotic properties.

Probiotics for prevention of atopic diseases in infants: systematic review and meta-analysis

Growing evidence underlines the pivotal role of infant gut colonization in the development of the immune system. The possibility to modify gut colonization through probiotic supplementation in childhood might prevent atopic diseases. The aim of the present systematic review and meta-analysis was to evaluate the effect of probiotic supplementation during pregnancy and early infancy in preventing atopic diseases. PubMed, Embase and Cochrane Library were searched for randomized controlled trials evaluating the use of probiotics during pregnancy or early infancy for prevention of allergic diseases. Fixed-effect models were used, and random-effects models where significant heterogeneity was present. Results were expressed as risk ratio (RR) with 95% confidence interval (CI). Seventeen studies, reporting data from 4755 children (2381 in the probiotic group and 2374 in the control group), were included in the meta-analysis. Infants treated with probiotics had a significantly lower RR for eczema compared to controls (RR 0.78 [95% CI: 0.69-0.89], P = 0.0003), especially those supplemented with a mixture of probiotics (RR 0.54 [95% CI: 0.43-0.68], P < 0.00001). No significant difference in terms of prevention of asthma (RR 0.99 [95% CI: 0.77-1.27], P = 0.95), wheezing (RR 1.02 [95% CI: 0.89-1.17], P = 0.76) or rhinoconjunctivitis (RR 0.91 [95% CI: 0.67-1.23], P = 0.53) was documented. The results of the present meta-analysis show that probiotic supplementation prevents infantile eczema, thus suggesting a new potential indication for probiotic use in pregnancy and infancy.

The gut microbiota and its role in the development of allergic disease: a wider perspective

The gut microbiota are critical in the homoeostasis of multiple interconnected host metabolic and immune networks. If early microbial colonization is delayed, the gut-associated lymphoid tissues (GALT) fail to develop, leading to persistent immune dysregulation in mice. Microbial colonization has also been proposed as a major driver for the normal age-related maturation of both Th1 and T regulatory (Treg) pathways that appear important in suppressing early propensity for Th2 allergic responses. There is emerging evidence that resident symbionts induce tolerogenic gut-associated Treg cells and dendritic cells that ensure the preferential growth of symbionts; keeping pathogenic strains in check and constraining proinflammatory Th1, Th2, and Th17 clones. Some effects of symbionts are mediated by short-chain fatty acids, which play a critical role in mucosal integrity and local and systemic metabolic function and stimulate the regulatory immune responses. The homoeostatic IL-10/TGF-β dominated tolerogenic response within the GALT also signals the production of secretory IgA, which have a regulating role in mucosal integrity. Contrary to the 'sterile womb' paradigm, recent studies suggest that maternal microbial transfer to the offspring begins during pregnancy, providing a pioneer microbiome. It is likely that appropriate microbial stimulation both pre- and postnatally is required for optimal Th1 and Treg development to avoid the pathophysiological processes leading to allergy. Disturbed gut colonization patterns have been associated with allergic disease, but whether microbial variation is the cause or effect of these diseases is still under investigation. We are far from understanding what constitutes a 'healthy gut microbiome' that promotes tolerance. This remains a major limitation and might explain some of the inconsistency in human intervention studies with prebiotics and probiotics. Multidisciplinary integrative approaches with researchers working in networks, using harmonized outcomes and methodologies, are needed to advance our understanding in this field.

Probiotics for the prevention of allergy: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Allergic diseases are considered a health burden because of their high and constantly increasing prevalence, high direct and indirect costs, and undesirable effects on quality of life. Probiotics have been suggested as an intervention to prevent allergic diseases.

OBJECTIVE

We sought to synthesize the evidence supporting use of probiotics for the prevention of allergies and inform World Allergy Organization guidelines on probiotic use.

METHODS

We performed a systematic review of randomized trials assessing the effects of any probiotic administered to pregnant women, breast-feeding mothers, and/or infants.

RESULTS

Of 2403 articles published until December 2014 identified in Cochrane Central Register of Controlled Trials, MEDLINE, and Embase, 29 studies fulfilled a priori specified inclusion criteria for the analyses. Probiotics reduced the risk of eczema when used by women during the last trimester of pregnancy (relative risk [RR], 0.71; 95% CI, 0.60-0.84), when used by breast-feeding mothers (RR, 0.57; 95% CI, 0.47-0.69), or when given to infants (RR, 0.80; 95% CI, 0.68-0.94). Evidence did not support an effect on other allergies, nutrition status, or incidence of adverse effects. The certainty in the evidence according to the Grading of Recommendation Assessment Development and Evaluation approach is low or very low because of the risk of bias, inconsistency and imprecision of results, and indirectness of available research.

CONCLUSION

Probiotics used by pregnant women or breast-feeding mothers and/or given to infants reduced the risk of eczema in infants; however, the certainty in the evidence is low. No effect was observed for the prevention of other allergic conditions.

Childhood obesity: a role for gut microbiota?

Obesity is a serious public health issue affecting both children and adults. Prevention and management of obesity is proposed to begin in childhood when environmental factors exert a long-term effect on the risk for obesity in adulthood. Thus, identifying modifiable factors may help to reduce this risk. Recent evidence suggests that gut microbiota is involved in the control of body weight, energy homeostasis and inflammation and thus, plays a role in the pathophysiology of obesity. Prebiotics and probiotics are of interest because they have been shown to alter the composition of gut microbiota and to affect food intake and appetite, body weight and composition and metabolic functions through gastrointestinal pathways and modulation of the gut bacterial community. As shown in this review, prebiotics and probiotics have physiologic functions that contribute to changes in the composition of gut microbiota, maintenance of a healthy body weight and control of factors associated with childhood obesity through their effects on mechanisms controlling food intake, fat storage and alterations in gut microbiota.

Probiotics in the prevention of eczema: a randomised controlled trial

OBJECTIVE

To evaluate a multistrain, high-dose probiotic in the prevention of eczema.

DESIGN

A randomised, double-blind, placebo-controlled, parallel group trial.

SETTINGS

Antenatal clinics, research clinic, children at home.

PATIENTS

Pregnant women and their infants.

INTERVENTIONS

Women from 36 weeks gestation and their infants to age 6 months received daily either the probiotic (Lactobacillus salivarius CUL61, Lactobacillus paracasei CUL08, Bifidobacterium animalis subspecies lactis CUL34 and Bifidobacterium bifidum CUL20; total of 10(10) organisms/day) or matching placebo.

MAIN OUTCOME MEASURE

Diagnosed eczema at age 2 years. Infants were followed up by questionnaire. Clinical examination and skin prick tests to common allergens were done at 6 months and 2 years.

RESULTS

The cumulative frequency of diagnosed eczema at 2 years was similar in the probiotic (73/214, 34.1%) and placebo arms (72/222, 32.4%; OR 1.07, 95% CI 0.72 to 1.6). Among the secondary outcomes, the cumulative frequency of skin prick sensitivity at 2 years was reduced in the probiotic (18/171; 10.5%) compared with the placebo arm (32/173; 18.5%; OR 0.52, 95% CI 0.28 to 0.98). The statistically significant differences between the arms were mainly in sensitisation to cow's milk and hen's egg proteins at 6 months. Atopic eczema occurred in 9/171 (5.3%) children in the probiotic arm and 21/173 (12.1%) in the placebo arm (OR 0.40, 95% CI 0.18 to 0.91).

CONCLUSIONS

The study did not provide evidence that the probiotic either prevented eczema during the study or reduced its severity. However, the probiotic seemed to prevent atopic sensitisation to common food allergens and so reduce the incidence of atopic eczema in early childhood.

TRIAL REGISTRATION NUMBER

ISRCTN26287422.

S3-Guideline on allergy prevention: 2014 update: Guideline of the German Society for Allergology and Clinical Immunology (DGAKI) and the German Society for Pediatric and Adolescent Medicine (DGKJ)

The continued high prevalence of allergic diseases in Western industrialized nations combined with the limited options for causal therapy make evidence-based primary prevention necessary. The recommendations last published in the S3-guideline on allergy prevention in 2009 have been revised and a consensus reached on the basis of an up-to-date systematic literature search.

Evidence was sought for the period between May 2008 and May 2013 in the Cochrane and MEDLINE electronic databases, as well as in the reference lists of recent review articles. In addition, experts were surveyed for their opinions. The relevance of retrieved literature was checked by means of two filter processes: firstly according to title and abstract, and secondly based on the full text of the articles. Included studies were given an evidence grade, and a bias potential (low/high) was specified for study quality. A formal consensus on the revised recommendations was reached by representatives of the relevant specialist societies and (self-help) organizations (nominal group process).

Of 3,284 hits, 165 studies (one meta-analysis, 15 systematic reviews, 31 randomized controlled trials, 65 cohort studies, 12 case-control studies and 41 cross-sectional studies) were included and evaluated. Recommendations on the following remain largely unaltered: full breastfeeding for 4 months as a means of allergy prevention (hypoallergenic infant formula in the case of infants at risk); avoidance of overweight; fish consumption (during pregnancy/lactation and in the introduction of solid foods for infants); vaccination according to the recommendations of the German Standing Committee on Vaccination (Ständige Impfkommission, STIKO); avoidance of air pollutants and tobacco exposure and avoidance of indoor conditions conducive to the development of mold. The assertion that a reduction in house-dust mite allergen content as a primary preventive measure is not recommended also remains unchanged. The introduction of solid foods into infant diet should not be delayed. In the case of children at risk cats should not be acquired as domestic pets. Keeping dogs is not associated with an increased risk of allergy. The updated guideline includes a new recommendation to consider the increased risk of asthma following delivery by cesarean section. Additional statements have been formulated on pre- and probiotic agents, psychosocial factors, medications, and various nutritional components.

Revising the guideline by using an extensive evidence base has resulted not only in an endorsement of the existing recommendations, but also in modifications and in the addition of new recommendations. The updated guideline enables evidence-based and up-to-date recommendations to be made on allergy prevention.

Probiotics and prebiotics in preventing food allergy and eczema

PURPOSE OF REVIEW

To describe the current literature on clinical trials of probiotics for eczema and food allergy prevention in view of recent new approaches and long-term follow-ups.

RECENT FINDINGS

Attempting allergy prevention by probiotic administration has been most successful when assessing atopic eczema, the most prevalent allergic disease at an early age. More than half of the published studies demonstrate a decrease in eczema prevalence until 2 years, whereas the remaining studies fail to show an effect. Effects have been most consistent with combined prenatal and direct postnatal supplementation of the infant and appear strain-specific, with Lactobacillus rhamnosus most often showing an effect. Prenatal-only and postnatal-only studies often fail to show effects. Recent long-time follow-ups have shown promising but not consistent results. A very recent follow-up of a large well conducted cohort shows that long-term effects of eczema prevention persists until age 4 and prevention of respiratory allergies might also be possible.

SUMMARY

Prevention of eczema with probiotics seem to work until age 2 years and extended effects until 4 years have been shown in high-risk for allergy cohorts. Effects are strain-specific, with L. rhamnosus showing the most consistent effects especially when combining pre and postnatal administration.

Is there a role for probiotics in the prevention or treatment of food allergy?

A balanced gut microbiota is crucial for the development of healthy immunoregulation and gut barrier function to allow brisk immune responses to pathogens and systemic hyporesponsiveness to harmless antigens such as food. Although the first allergic disease to manifest itself, atopic eczema, is not equivalent to food allergy, pre- and postnatal administration of specific probiotic strains has emerged as a promising tool for the prevention of this condition, with potential implications for food allergy development. For food allergy proper, however, we lack markers and risk factors and mechanisms, i.e., targets for preventive measures. The focus here is therefore on the treatment. Indeed, the potential of specific probiotic strains to alleviate food allergy resides in their ability to modify antigens, repair gut barrier functions, balance altered microbiota, and restore local and systemic immune regulation. In patients with multiple food allergies, induction of oral tolerance by specific probiotics continues to attract research interest.

Probiotic milk consumption in pregnancy and infancy and subsequent childhood allergic diseases

BACKGROUND

Whether probiotics, which can influence the microbiome, prevent infant eczema or allergic disease remains an open question. Most studies have focused on high-risk infants.

OBJECTIVES

We sought to assess whether consumption of probiotic milk products protects against atopic eczema, rhinoconjunctivitis, and asthma in early childhood in a large population-based pregnancy cohort (the Norwegian Mother and Child Cohort study).

METHODS

We examined associations between consumption of probiotic milk products in pregnancy and infancy with questionnaire-reported atopic eczema, rhinoconjunctivitis, and asthma in 40,614 children. Relative risks (RRs) were calculated by using general linear models adjusted for potential confounders.

RESULTS

Consumption of probiotic milk in pregnancy was associated with a slightly reduced relative risk (RR) of atopic eczema at 6 months (adjusted RR, 0.94; 95% CI, 0.89-0.99) and of rhinoconjunctivitis between 18 and 36 months (adjusted RR, 0.87; 95% CI, 0.78-0.98) compared with no consumption during pregnancy. Maternal history of allergic disease did not notably influence the associations. When both the mother (during pregnancy) and infant (after 6 months of age) had consumed probiotic milk, the adjusted RR of rhinoconjunctivitis was 0.80 (95% CI, 0.68-0.93) relative to no consumption by either. Probiotic milk consumption was not associated with asthma at 36 months.

CONCLUSIONS

In this population-based cohort consumption of probiotic milk products was related to a reduced incidence of atopic eczema and rhinoconjunctivitis, but no association was seen for incidence of asthma by 36 months of age.

Maternal Supplementation with LGG Reduces Vaccine-Specific Immune Responses in Infants at High-Risk of Developing Allergic Disease

Probiotics are defined as live micro-organisms that when administered in adequate amounts confer a health benefit on the host. Among their pleiotropic effects, inhibition of pathogen colonization at the mucosal surface as well as modulation of immune responses are widely recognized as the principal biological activities of probiotic bacteria. In recent times, the immune effects of probiotics have led to their application as vaccine adjuvants, offering a novel strategy for enhancing the efficacy of current vaccines. Such an approach is particularly relevant in regions where infectious disease burden is greatest and where access to complete vaccination programs is limited. In this study, we report the effects of the probiotic, Lactobacillus rhamnosus GG (LGG) on immune responses to tetanus, Haemophilus influenzae type b (Hib) and pneumococcal conjugate (PCV7) vaccines in infants. This study was conducted as part of a larger clinical trial assessing the impact of maternal LGG supplementation in preventing the development of atopic eczema in infants at high-risk for developing allergic disease. Maternal LGG supplementation was associated with reduced antibody responses against tetanus, Hib, and pneumococcal serotypes contained in PCV7 (N = 31) compared to placebo treatment (N = 30) but not total IgG levels. Maternal LGG supplementation was also associated with a trend to increased number of tetanus toxoid-specific T regulatory in the peripheral blood compared to placebo-treated infants. These findings suggest that maternal LGG supplementation may not be beneficial in terms of improving vaccine-specific immunity in infants. Further clinical studies are needed to confirm these findings. As probiotic immune effects can be species/strain specific, our findings do not exclude the potential use of other probiotic bacteria to modulate infant immune responses to vaccines.

Neonatal colonization of germ-free mice with Bifidobacterium longum prevents allergic sensitization to major birch pollen allergen Bet v 1

The main goal in reversing the allergy epidemic is the development of effective prophylactic strategies. We investigated the prophylactic effect of neonatal mother-to-offspring mono-colonization with Bifidobacterium longum ssp. longum CCM 7952 on subsequent allergic sensitization. Adult male and female germ-free (GF) mice were mono-colonized with B. longum, mated and their offspring, as well as age-matched GF controls, were sensitized with the major birch pollen allergen Bet v 1. Furthermore, signaling pathways involved in the recognition of B. longum were investigated in vitro. Neonatal mono-colonization of GF mice with B. longum suppressed Bet v 1-specific IgE-dependent β-hexosaminidase release as well as levels of total IgE and allergen-specific IgG2a in serum compared to sensitized GF controls. Accordingly, Bet v 1-induced production of both Th1- and Th2-associated cytokines in spleen cell cultures was significantly reduced in these mice. The general suppression of Bet v 1-specific immune responses in B. longum-colonized mice was associated with increased levels of regulatory cytokines IL-10 and TGF-β in serum. In vitro, B. longum induced low maturation status of bone marrow-derived dendritic cells and production of IL-10 in TLR2-, MyD88-, and MAPK-dependent manner. Our data demonstrate that neonatal mono-colonization with B. longum reduces allergic sensitization, likely by activation of regulatory responses via TLR2, MyD88, and MAPK signaling pathways. Thus, B. longum might be a promising candidate for perinatal intervention strategies against the onset of allergic diseases in humans.

Prenatal and childhood infections: implications for the development and treatment of childhood asthma

Bacterial and viral infections occur early and recurrently in life and thereby impose a substantial disease burden. Besides causing clinical symptoms, a potential role of infection in the development of the asthma syndrome later in life has also been suggested. However, whether bacterial and viral infections unmask host factors in children at risk of asthma or whether they directly cause asthma remains unclear; both viewpoints could be justified, but the underlying mechanisms are complex and poorly understood. Recently, the role of the bacterial microbiome has been emphasised. But data are still sparse and future studies are needed for definitive conclusions to be made. In this Review, we discuss present knowledge of viruses and bacteria that infect and colonise the respiratory tract and mucosal surfaces, including their timepoint of action, host factors related to infection, and their effect on childhood asthma. Childhood asthma could be the result of a combination of altered host susceptibility and infectious agents.

Clinical effects of probiotics: scientific evidence from a paediatric perspective

Probiotics are live micro-organisms that when given in adequate amounts can cause health benefits. The safety and efficacy of probiotics in the prevention and treatment of various clinical conditions have been evaluated in randomised controlled clinical trials, systematic reviews and meta-analyses. Generally, their safety has been documented. As a supplement to standard rehydration therapy, probiotics have been demonstrated to shorten the duration of diarrhoea resulting from acute viral gastroenteritis and in preventing antibiotic-associated diarrhoea in healthy children. Preliminary evidence suggests that probiotics might prevent necrotising enterocolitis in very-low-birth-weight infants, but further studies are needed before definite conclusions can be drawn. Probiotics have also been assessed in the treatment and prevention of allergic disease but the results, although promising, need further confirmation. Targeting a paediatric population, probiotics have been evaluated in the treatment of irritable bowel syndrome, ulcerative colitis, Helicobacter pylori gastritis and infantile colic, but at this stage, there is no evidence to support their routine use for these indications. There is a great need for studies aiming at disentangling the mechanisms by which probiotics mediate their clinical effects and for comparative studies between various probiotic bacteria. We still need to know which probiotic(s) to use and for which indications. A clearer message on dosages, optimal timing and duration of administration is needed. For this purpose, more carefully designed and sufficiently powered, randomised controlled trials with predefined outcomes are needed.

Anaphylactic reaction to probiotics. Cow's milk and hen's egg allergens in probiotic compounds

BACKGROUND

Probiotics are used in the treatment of allergic diseases. We investigated the safety of probiotics for subjects with food allergy.

MATERIAL AND METHODS

Labels of probiotics commercially available in Spain were examined to assess their content of cow's milk or hen's egg. Skin prick tests with these compounds (20 mg/ml) were performed in five children allergic to cow's milk, five children allergic to hen's white egg, and five control subjects non-allergic to food. Three serum pools: I (positive-specific IgE to cow's milk and hen's egg white proteins), II (positive-specific IgE to cow's milk and negative to hen's egg white proteins), and III (negative-specific IgE to cow's milk and positive to hen's egg white proteins) were used to detect cow's milk and hen's egg white allergens in probiotics. ImmunoCAP(®) (Phadia), in-house ELISA, SDS-PAGE immunoblotting, and inhibition studies of these assays were performed. Proteins were quantified by enzyme-immunoassay.

RESULTS

Eleven probiotics were studied. No label advertised about egg content, eight labels warned about lactose, lactic acid or cow's milk, one label claimed to be milk-free, and two gave no information. Cow's milk proteins were detected, by at least one lab technique, in 10/11 probiotics, three over 2.5 mg/kg (21, 52, 112 mg/kg). Hen's egg white proteins were detected in 3/11 probiotics, only one had more than 2.5 mg/kg (47 mg/kg).

CONCLUSION

Probiotic compounds may contain hidden allergens of food and may not be safe for subjects with allergy to cow's milk or hen's egg.

Immune factors in breast milk and the development of atopic disease

Breast-feeding provides protection against infections and contains numerous factors that modulate and promote the development of the infant immune system. These factors include secretory IgA, antimicrobial proteins like CD14, cytokines, and fatty acids. Studies examining the role of breast-feeding in the development of allergic disease in infants demonstrate potentially protective as well as neutral or nonprotective effects, likely due to the heterogeneity in their study design. In this overview, we explore the potential role of immune factors in the breast milk, as well as selected probiotics, in the development of allergy.

Reduced gut microbial diversity in early life is associated with later development of eczema but not atopy in high-risk infants

BACKGROUND

Alterations in intestinal microflora have been linked to the development of allergic disease. Recent studies suggest that healthy infant immune development may depend on the establishment of a diverse gut microbiota rather than the presence or absence of specific microbial strains.

OBJECTIVES

We investigated the relationship between diversity of gut microbiota in the early postnatal period and subsequent development of eczema and atopy in the first year of life.

METHODS

Fecal samples were collected 1 wk after birth from 98 infants at high risk of allergic disease, who were followed prospectively to age 12 months. Fecal microbial diversity was assessed by terminal restriction fragment length polymorphism (T-RFLP) using restriction enzymes Sau96I and AluI, with a greater number of peaks representing greater diversity of bacterial communities.

RESULTS

Microbial diversity at day 7 was significantly lower in infants with eczema at age 12 months as compared to infants without eczema (AluI mean number of peaks 13.1 vs. 15.5, p = 0.003, 95% CI for difference in means -3.9, -0.8; Sau96I 14.7 vs. 17.2, p = 0.03, 95% CI -4.9, -0.3). No differences were observed for atopic compared to non-atopic infants, or infants with two allergic parents compared to those with one or no allergic parent.

CONCLUSIONS

A more diverse intestinal microbiota in the first week of life is associated with a reduced risk of subsequent eczema in infants at increased risk of allergic disease. Interventions that enhance microbial diversity in early life may provide an effective means for the prevention of eczema in high-risk infants.

Clinical Use of Probiotics in Pediatric Allergy (CUPPA): A World Allergy Organization Position Paper

BACKGROUND

: Probiotic administration has been proposed for the prevention and treatment of specific allergic manifestations such as eczema, rhinitis, gastrointestinal allergy, food allergy, and asthma. However, published statements and scientific opinions disagree about the clinical usefulness.

OBJECTIVE

: A World Allergy Organization Special Committee on Food Allergy and Nutrition review of the evidence regarding the use of probiotics for the prevention and treatment of allergy.

METHODS

: A qualitative and narrative review of the literature on probiotic treatment of allergic disease was carried out to address the diversity and variable quality of relevant studies. This variability precluded systematization, and an expert panel group discussion method was used to evaluate the literature. In the absence of systematic reviews of treatment, meta-analyses of prevention studies were used to provide data in support of probiotic applications.

RESULTS

: Despite the plethora of literature, probiotic research is still in its infancy. There is a need for basic microbiology research on the resident human microbiota. Mechanistic studies from biology, immunology, and genetics are needed before we can claim to harness the potential of immune modulatory effects of microbiota. Meanwhile, clinicians must take a step back and try to link disease state with alterations of the microbiota through well-controlled long-term studies to identify clinical indications.

CONCLUSIONS

: Probiotics do not have an established role in the prevention or treatment of allergy. No single probiotic supplement or class of supplements has been demonstrated to efficiently influence the course of any allergic manifestation or long-term disease or to be sufficient to do so. Further epidemiologic, immunologic, microbiologic, genetic, and clinical studies are necessary to determine whether probiotic supplements will be useful in preventing allergy. Until then, supplementation with probiotics remains empirical in allergy medicine. In the future, basic research should focus on homoeostatic studies, and clinical research should focus on preventive medicine applications, not only in allergy. Collaborations between allergo-immunologists and microbiologists in basic research and a multidisciplinary approach in clinical research are likely to be the most fruitful.

A protective effect of Lactobacillus rhamnosus HN001 against eczema in the first 2 years of life persists to age 4 years

BACKGROUND

Using a double blind randomized placebo-controlled trial (Australian New Zealand Clinical Trials Registry: ACTRN12607000518460), we have shown that in a high risk birth cohort, maternal supplementation from 35 weeks gestation until 6 months if breastfeeding and infant supplementation until 2 years with Lactobacillus rhamnosus HN001 (HN001) (6 × 10(9) cfu/day) halved the cumulative prevalence of eczema by age 2 years. Bifidobacterium animalis subsp lactis HN019 (HN019) (9 × 10(9) cfu/day) had no effect.

OBJECTIVE

The aim of this study was to investigate the associations of HN001 and HN019 with allergic disease and atopic sensitization among these children at age 4 years, 2 years after stopping probiotic supplementation.

METHODS

The presence (UK Working Party's Diagnostic Criteria) and severity SCORing Atopic Dermatitis (SCORAD) of eczema and atopy (skin prick tests) and parent-reported symptoms of asthma and rhinoconjunctivitis were assessed using standard protocols and questions.

RESULTS

Four-hundred and seventy-four infants were eligible at birth of whom 425 (90%) participated in this follow-up. The cumulative prevalence of eczema by 4 years (Hazard ratio (HR) 0.57 (95% CI 0.39-0.83)) and prevalence of rhinoconjunctivitis at 4 years (Relative risk 0.38 (95% CI 0.18-0.83)) were significantly reduced in the children taking HN001; there were also nonsignificant reductions in the cumulative prevalence of SCORAD ≥ 10 (HR 0.74 (95% CI 0.52-1.05), wheeze (HR 0.79 (95% CI 0.59-1.07)) and atopic sensitization (HR = 0.72 (95% CI 0.48-1.06)). HN019 did not affect the prevalence of any outcome.

CONCLUSIONS AND CLINICAL RELEVANCE

This study showed that the protective effect of HN001 against eczema, when given for the first 2 years of life only, extended to at least 4 years of age. This, together with our findings for a protective effect against rhinoconjunctivitis, suggests that this probiotic might be an appropriate preventative intervention for high risk infants.

Probiotic therapy as a novel approach for allergic disease

The prevalence of allergic disease has increased dramatically in Western countries over the past few decades. The hygiene hypothesis, whereby reduced exposure to microbial stimuli in early life programs the immune system toward a Th2-type allergic response, is suggested to be a major mechanism to explain this phenomenon in developed populations. Such microbial exposures are recognized to be critical regulators of intestinal microbiota development. Furthermore, intestinal microbiota has an important role in signaling to the developing mucosal immune system. Intestinal dysbiosis has been shown to precede the onset of clinical allergy, possibly through altered immune regulation. Existing treatments for allergic diseases such as eczema, asthma, and food allergy are limited and so the focus has been to identify alternative treatment or preventive strategies. Over the past 10 years, a number of clinical studies have investigated the potential of probiotic bacteria to ameliorate the pathological features of allergic disease. This novel approach has stemmed from numerous data reporting the pleiotropic effects of probiotics that include immunomodulation, restoration of intestinal dysbiosis as well as maintaining epithelial barrier integrity. In this mini-review, the emerging role of probiotics in the prevention and/or treatment of allergic disease are discussed with a focus on the evidence from animal and human studies.

Transcriptional analysis of prebiotic uptake and catabolism by Lactobacillus acidophilus NCFM

The human gastrointestinal tract can be positively modulated by dietary supplementation of probiotic bacteria in combination with prebiotic carbohydrates. Here differential transcriptomics and functional genomics were used to identify genes in Lactobacillus acidophilus NCFM involved in the uptake and catabolism of 11 potential prebiotic compounds consisting of α- and β- linked galactosides and glucosides. These oligosaccharides induced genes encoding phosphoenolpyruvate-dependent sugar phosphotransferase systems (PTS), galactoside pentose hexuronide (GPH) permease, and ATP-binding cassette (ABC) transporters. PTS systems were upregulated primarily by di- and tri-saccharides such as cellobiose, isomaltose, isomaltulose, panose and gentiobiose, while ABC transporters were upregulated by raffinose, Polydextrose, and stachyose. A single GPH transporter was induced by lactitol and galactooligosaccharides (GOS). The various transporters were associated with a number of glycoside hydrolases from families 1, 2, 4, 13, 32, 36, 42, and 65, involved in the catabolism of various α- and β-linked glucosides and galactosides. Further subfamily specialization was also observed for different PTS-associated GH1 6-phospho-β-glucosidases implicated in the catabolism of gentiobiose and cellobiose. These findings highlight the broad oligosaccharide metabolic repertoire of L. acidophilus NCFM and establish a platform for selection and screening of both probiotic bacteria and prebiotic compounds that may positively influence the gastrointestinal microbiota.