Meta-analysis of clinical trials of probiotics for prevention and treatment of pediatric atopic dermatitis

Human mucosal in vivo transcriptome responses to three lactobacilli indicate how probiotics may modulate human cellular pathways

Probiotic bacteria, specific representatives of bacterial species that are a common part of the human microbiota, are proposed to deliver health benefits to the consumer by modulation of intestinal function through largely unknown molecular mechanisms. To explore in vivo mucosal responses of healthy adults to probiotics, we obtained transcriptomes in an intervention study after a double-blind placebo-controlled cross-over design. In the mucosa of the proximal small intestine of healthy volunteers, probiotic strains from the species Lactobacillus acidophilus, L. casei, and L. rhamnosus each induced differential gene-regulatory networks and pathways in the human mucosa. Comprehensive analyses revealed that these transcriptional networks regulate major basal mucosal processes and uncovered remarkable similarity to response profiles obtained for specific bioactive molecules and drugs. This study elucidates how intestinal mucosa of healthy humans perceives different probiotics and provides avenues for rationally designed tests of clinical applications.

Well-controlled proinflammatory cytokine responses of Peyer's patch cells to probiotic Lactobacillus casei

SUMMARY

In order to clarify the probiotic features of immunomodulation, cytokine production by murine spleen and Peyer's patch (PP) cells was examined in response to probiotic and pathogenic bacteria. In spleen cells, probiotic Lactobacillus casei induced interleukin (IL)-12 production by CD11b(+) cells more strongly than pathogenic Gram-positive and Gram-negative bacteria and effectively promoted the development of T helper (Th) type 1 cells followed by high levels of secretion of interferon (IFN)-gamma. Although the levels of IL-12 secreted by PP cells in response to L. casei were lower in comparison with spleen cells, Th1 cells developed as a result of this low-level induction of IL-12. However, IFN-gamma secretion by the L. casei-induced Th1 cells stimulated with a specific antigen was down-regulated in PP cells. Development of IL-17-producing Th17 cells was efficiently induced in PP cells by antigen stimulation. Lactobacillus casei slightly, but significantly, inhibited the antigen-induced secretion of IL-17 without a decrease in the proportion of Th17 cells. No bacteria tested induced the development of IL-10-producing, transforming growth factor-beta-producing or Foxp3-expressing regulatory T cells, thus suggesting that certain probiotics might regulate proinflammatory responses through as yet unidentified mechanisms in PP cells. These data show probiotic L. casei to have considerable potential to induce IL-12 production and promote Th1 cell development, but the secretion of proinflammatory cytokines such as IL-12 and IL-17 may be well controlled in PP cells.

A pilot study of emollient therapy for the primary prevention of atopic dermatitis

BACKGROUND

Prevention strategies in atopic dermatitis (AD) using allergen avoidance have not been consistently effective. New research reveals the importance of the skin barrier in the development of AD and possibly food allergy and asthma. Correcting skin barrier defects from birth may prevent AD onset or moderate disease severity.

OBJECTIVE

We sought to determine the feasibility of skin barrier protection as a novel AD prevention strategy.

METHODS

We enrolled 22 neonates at high risk for developing AD in a feasibility pilot study using emollient therapy from birth.

RESULTS

No intervention-related adverse events occurred in our cohort followed up for a mean time of 547 days. Of the 20 subjects who remained in the study, 3 (15.0%) developed AD, suggesting a protective effect when compared with historical controls. Skin barrier measurements remained within ranges seen in normal-appearing skin.

LIMITATIONS

No conclusions regarding efficacy can be made without a control group.

CONCLUSIONS

Skin barrier repair from birth represents a novel and feasible approach to AD prevention. Further studies are warranted to determine the efficacy of this approach.

Effect of Lactobacillus sakei supplementation in children with atopic eczema-dermatitis syndrome

BACKGROUND

Probiotics have been suggested to be useful in children with atopic eczema-dermatitis syndrome (AEDS).

OBJECTIVE

To assess the clinical effect of Lactobacillus sakei supplementation in children with AEDS.

METHODS

In a double-blind, placebo-controlled trial, children aged 2 to 10 years with AEDS with a minimum SCORing of Atopic Dermatitis (SCORAD) score of 25 were randomized to receive either daily L sakei KCTC 10755BP or daily placebo supplementation for 12 weeks. Changes in SCORAD scores and serum chemokine levels from baseline were evaluated.

RESULTS

Eighty-eight children were enrolled, and 45 were allocated to probiotic treatment. Seventy-five children completed the study, with 4 dropouts in the probiotic group and 9 in the placebo group. At week 12, SCORAD total scores adjusted by pretreatment values were lower after probiotic treatment than after placebo treatment (P = .01). There was a 31% (13.1-point) improvement in mean disease activity with probiotic use compared with a 13% (5.2-point) improvement with placebo use (P = .008). Significant differences in favor of probiotic treatment were also observed in proportions of patients achieving improvement of at least 30% and 50%. Compared with placebo, probiotic administration was associated with lower pretreatment-adjusted serum levels of CCL17 and CCL27 (P =.03 for both), which were significantly correlated with SCORAD total score (r = 0.59 and 0.63, respectively; P < .001).

CONCLUSIONS

Supplementation of L sakei in children with AEDS was associated with a substantial clinical improvement and a significant decrease in chemokine levels, reflecting the severity of AEDS.

Oral supplementation with Lactobacillus rhamnosus CGMCC 1.3724 prevents development of atopic dermatitis in NC/NgaTnd mice possibly by modulating local production of IFN-gamma

Prevalence of allergies has increased during the last two decades. Alteration of the gut microbiota composition is thought to play a crucial role in development of atopic diseases. Oral administration of probiotics has been reported to treat and/or prevent symptoms of atopic diseases in infants, but the results are still controversial. We investigated the potential efficacy of dietary interventions by a probiotic strain on prevention and treatment of atopic dermatitis (AD) in a human-like AD model, NC/NgaTnd mice by perinatal administration. Pregnant NC/NgaTnd mice were orally treated with the probiotic strain Lactobacillus rhamnosus CGMCC 1.3724 (LPR), which was followed by treatment of pups until 12 weeks of age. LPR-treated mice exhibited significant lower clinical symptoms of dermatitis, reduced scratching frequency, lower levels of plasma total Immunoglobulin E and higher levels of interferon-gamma in skin biopsies, compared with untreated mice. The protective effect was also observed when mice started to be treated at weaning time (5 weeks of age) even with limited supplementation period of 2 weeks. However, treatment of mice with the probiotic starting 1 week after the onset of the disease (8 weeks of age) had limited effects. The usefulness of LPR for primary prevention of AD was supported.

Lactobacillus reuteri modulates cytokines production in exhaled breath condensate of children with atopic dermatitis

We measured the concentration of interferon-gamma and interleukin-4 in the exhaled breath condensate of children with atopic and nonallergic dermatitis receiving a probiotic supplementation (Lactobacillus reuteri ATCC 55730) or placebo for 8 weeks. We demonstrated that the levels of these cytokines increased and decreased respectively only in atopic subjects receiving active treatment. Our data suggest that the oral administration of a specific probiotic strain in patients with atopic dermatitis can modulate in vivo the cytokine pattern at a different site from intestine.

Practical prebiotics, probiotics and synbiotics for allergists: how useful are they?

With the advent of the hygiene hypothesis, probiotics have provided an avenue of hope in curbing the allergic epidemic. The initial enthusiasm has been tempered by recognition of the inherent complexities of this approach. This review examines the current clinical evidence and practical issues in using probiotics and related products, for the prevention and treatment of allergic disease. So far, probiotics have shown more promise, albeit limited, in the primary prevention of allergic disease rather than in the treatment of established disease. These effects have largely been limited to the prevention of early childhood conditions such as eczema, with no consistent effects on other allergic outcomes. There is emerging evidence that clinical effects may be strain specific, but again these findings have been inconsistent. While there have been several meta-analyses to examine probiotics in both the prevention and the treatment of allergic disease, these have been hampered by significant heterogeneity between studies, including wide variations in the strains used, the methods and timing of administration and the age and assessment of allergic outcomes. In any case, these have also become outdated by a series of new studies published in the last year. Although it is not yet clear exactly how the growing number of new studies will modify the results of meta-analyses, it is likely that these will add yet further heterogeneity that will continue to make interpretation of pooled data difficult. At this stage, the effects of prebiotics, synbiotics and postbiotics are even less clear. Thus, while there is little doubt that microbiota modulate immune development and can prevent the allergic phenotype, the optimal way of achieving this is far from clear. Given the current level of evidence, it is not appropriate to recommend prebiotics/probiotics/synbiotics or postbiotics as a part of standard therapy or for the prevention of any allergic conditions. Further studies are needed to address the growing speculation that supplementation with a single probiotic strain may be oversimplistic and that approaches that have a more global effect on colonization may be warranted.

Various effects of different probiotic strains in allergic disorders: an update from laboratory and clinical data

Epidemiological data show that allergic children have a different intestinal flora from healthy children with higher levels of Clostridia and lower levels of Bifidobacteria. Nonetheless, Bifidobacteria and Lactobacilli are found more commonly in the composition of the intestinal flora of non-allergic children. Probiotics are ingested live microbes that can modify intestinal microbial populations in a way that benefits the host and they are represented mainly by Lactobacilli. Enhanced presence of probiotic bacteria in the intestinal microbiota is found to correlate with protection against atopy. There is also very promising evidence to recommend the addition of probiotics to foods for the prevention and treatment of allergic diseases. Clinical improvement, especially in allergic rhinitis and immunoglobulin (Ig)E-sensitized (atopic) eczema, has been reported in most of the published studies. However, clinical benefit of probiotic therapy depends upon numerous factors, such as type of bacterium, dosing regimen, delivery method and other underlying host factors, e.g. the age and diet of the host. Selection of the most beneficial probiotic strain, the dose and the timing of supplementation still need to be determined. This review helps understanding of the role of probiotics in various allergic diseases, explaining laboratory and clinical data in light of recent literature.

Early exposure to antibiotics and infections and the incidence of atopic eczema: a population-based cohort study

It has been suggested that infants exposed to antibiotics are at increased risk for atopic eczema (AE), whereas the early exposure to infections might be protective. This study describes the complex relationship between early exposure to infections, anti-infectious treatment with antibiotics, and incident AE. Using a German population-based administrative health-care and prescription database, we established a cohort of 370 children not diagnosed as having AE during their first year of life. For each individual child we identified all infections and prescriptions of antibiotics within the first year as well as incident AE within the second year of life. Crude analyses suggested that early infections and exposure to antibiotics are risk factors for AE. However, stratified analyses indicated that early infections were only associated with a higher rate of AE when treated with broad-spectrum antibiotics such as cephalosporines or macrolides. The risk ratio (RR) of children with early respiratory tract infections not treated with antibiotics was 0.69 [95% confidence interval (95% CI) 0.39 to 1.24], whereas respiratory tract infections treated with macrolides (RR: 2.15, 95% CI: 1.18-3.91) or cephalosporines (RR: 1.93, 95% CI: 1.07-3.49) significantly increased the risk for AE. The results for other common childhood infections tended to be similar. Antibiotic treatment appears to modify the association between early infections and subsequent AE. We found no evidence that infections per se significantly alter the likelihood for subsequent AE.

Probiotics and prebiotics in atopic dermatitis: review of the theoretical background and clinical evidence

The prevalence of atopic dermatitis (AD) has risen over the past decades, especially in western societies. According to the revised hygiene hypothesis this increase is caused by a changed intestinal colonization pattern during infancy, which has an impact on the immune system. Manipulating the intestinal microflora with pro-, pre- or synbiotics is an innovative way to prevent or treat AD. This review provides an overview of the theoretical basis for using probiotics and prebiotics in AD and presents the current evidence from randomized controlled trials (RCTs) regarding prevention and treatment of AD and food allergy in children with pro-, pre- and synbiotics. Seven RCTs on prevention and 12 RCTs on treatment were found by searching the Pubmed, Embase and Cochrane databases. Results of these trials are conflicting. In conclusion, at this moment there is not enough evidence to support the use of pro-, pre- or synbiotics for prevention or treatment of AD in children in clinical practice.

Prebióticos, probióticos e simbióticos na prevenção e tratamento das doenças alérgicas

OBJETIVO: Avaliar o papel dos probióticos, prebióticos e simbióticos no equilíbrio do sistema imunológico do lactente, bem como seu efeito preventivo no desenvolvimento de doenças alérgicas na criança. FONTE DE DADOS: A partir do levantamento de todos os ensaios clínicos duplo-cegos e randômicos em seres humanos, publicados nos últimos cinco anos na base de dados Medline e que contivessem unitermos relacionados a prebióticos (oligossacarídeos), probióticos e simbióticos versus hipersensibilidade, analisou-se seu papel quanto à utilização em doenças alérgicas. SÍNTESE DE DADOS: Foram incluídos nesta revisão três trabalhos com prebióticos, os quais utilizaram a mistura GOS:FOS (9:1) em fórmulas infantis em lactentes nos primeiros meses de vida; 24 trabalhos com probióticos, sendo os micro-organismos utilizados na suplementação L. rhamnosus GG, B. lactis, L. casei, L. paracasei, L. reuteri, L. acidophilus, B. longum, B. breve e P. freudenreichii sp., e dois estudos com simbióticos. CONCLUSÕES: Apesar das evidências de benefícios da suplementação precoce de probióticos com algumas cepas específicas, prebióticos e simbióticos na prevenção da dermatite atópica, em crianças de alto risco para alergias, e do uso de probióticos no tratamento das dermatites atópicas moderadas e graves mediadas por IgE, há necessidade de ampliar os estudos quanto ao tempo de observação dos indivíduos suplementados, quanto à segurança e aos efeitos em longo prazo

Recent insights into atopic dermatitis and implications for management of infectious complications

Atopic dermatitis (AD) is a common complex disease that frequently follows a chronic relapsing course and affects the quality of life of patients and families in a significant manner. New insights into the pathophysiology of AD point to an important role of structural abnormalities in the epidermis combined with immune dysregulation. Patients with AD have a unique predisposition to colonization or infection by a number of microbial organisms, most notably Staphylococcus aureus and herpes simplex virus. A multipronged approach directed at healing or protecting the skin barrier and addressing the immune dysregulation is necessary to improve the likelihood of successful outcomes.

Cord blood cytokines are modulated by maternal farming activities and consumption of farm dairy products during pregnancy: the PASTURE Study

BACKGROUND

Traditional farming represents a unique model situation to investigate the relationship of early-life farm-related exposure and allergy protection.

OBJECTIVES

To investigate associations between maternal farm exposures and cytokine production in cord blood (CB) mononuclear cells in a prospective multinational birth cohort of 299 farm and 326 nonfarm children and their families.

METHODS

Supernatants from phorbol 12-myristate 13-acetate/ionomycin-stimulated CB mononuclear cells were assessed for the production of IFN-gamma, TNF-alpha, IL-5, IL-10, and IL-12.

RESULTS

Significantly higher levels of IFN-gamma and TNF-alpha in farm compared with nonfarm children were found, whereas IL-5, IL-10, and IL-12 levels did not differ between study groups. Maternal contact with different farm animal species and barns and consumption of farm-produced butter during pregnancy enhanced the production of proinflammatory CB cytokines, whereas maternal consumption of farm-produced yogurt resulted in significant lower levels of IFN-gamma and TNF-alpha in umbilical blood.

CONCLUSION

Maternal exposure to farming activities and farm dairy products during pregnancy modulated cytokine production patterns of offspring at birth.

Neonatal innate immunity in allergy development

PURPOSE OF REVIEW

The neonate is born with a distinct immune system that is biased against the production of T-helper cell 1 (Th1) cytokines. Birth imposes a great challenge on the neonatal immune system, which is confronted with an outside world rich in foreign antigens. Exposure to these antigens shapes the developing neonatal immune system. Inducing Th-1 or Th-2 polarized responses that may extend beyond the neonatal age and counteract or promote allergic sensitization. This review describes how engagement of the innate immune system might contribute to the development of allergy in children.

RECENT FINDINGS

The exact role of innate immune stimulation in the development of allergies is a controversial area. Epidemiological literature suggests that microbial exposure in early childhood protects against the development of allergies, whereas a large amount of experimental data demonstrates that innate immune stimulation enhances Th2 responses upon primary and secondary antigen exposure.

SUMMARY

Dose, site and timing of allergen exposure are likely to modulate the innate immune response, polarizing the maturing neonatal immune system towards Th1 or Th2-type responses, thereby protecting from or predisposing to asthma and allergies. Modulation of neonatal innate immune responses may be a novel approach to prevent asthma and allergies.

Allergic skin diseases

The skin is one of the largest immunologic organs and is affected by both external and internal factors, as well as innate and adaptive immune responses. Many skin disorders, such as atopic dermatitis, contact dermatitis, urticaria, angioedema, psoriasis, and autoimmune blistering disorders, are immune mediated. Most of these diseases are chronic, inflammatory, and proliferative, in which both genetic and environmental factors play important roles. These immunologic mechanisms might have implications for potential targets of future therapeutic interventions.

Allergic skin disease: major highlights and recent advances

AD, urticaria, and ACD account for a large percentage of the skin disorders that present at medical offices and emergency departments. With a high degree of morbidity, these diseases can be extremely difficult to manage. Consequently, these diseases continue to be the focus of much of the new research in the field. Recent studies have furthered the understanding of the complex relationship between immune and nonimmune factors in the pathogenesis of these disorders. This research has quickly led to the development of new treatment modalities and protocols for patient care, especially for AD. However, further discovery will be necessary to optimize the management of these often-vexing conditions.

The role of probiotics in allergic diseases

Allergic disorders are very common in the pediatric age group. While the exact etiology is unclear, evidence is mounting to incriminate environmental factors and an aberrant gut microbiota with a shift of the Th1/Th2 balance towards a Th2 response. Probiotics have been shown to modulate the immune system back to a Th1 response. Several in vitro studies suggest a role for probiotics in treating allergic disorders. Human trials demonstrate a limited benefit for the use of probiotics in atopic dermatitis in a preventive as well as a therapeutic capacity. Data supporting their use in allergic rhinitis are less robust. Currently, there is no role for probiotic therapy in the treatment of bronchial asthma. Future studies will be critical in determining the exact role of probiotics in allergic disorders.

Molecular crosstalk of probiotic bacteria with the intestinal immune system: clinical relevance in the context of inflammatory bowel disease

It is current knowledge that the intestinal microbiota plays a major role in the development and maintenance of intestinal health. Intestinal epithelial cells (IEC) constitute the interface between the gut lumen and the innate and adaptive immune system. To maintain intestinal homeostasis, the organized and diffuse compartments of the gut-associated lymphoid tissue have to process the continuously varying information at the interface between the luminal side and the host. Dysregulated intestinal immune responses towards commensal bacteria are an important factor in the pathogenesis of inflammatory bowel diseases (IBD). In contrast to the colitogenic effects of enteric bacteria, clinical and experimental studies showed that specific probiotic strains are protective in the context of chronic intestinal inflammation. Although the molecular understanding of bacteria-host interaction is improving, the anti-inflammatory mechanisms induced by these probiotic bacteria are just starting to be unraveled. The present review is meant to summarize and discuss the clinical relevance of probiotics, but it also seeks to give an overview about currently known probiotic mechanisms in the context of chronic intestinal inflammation with a focus on IEC.

Probiotic lactobacilli in breast milk and infant stool in relation to oral intake during the first year of life

OBJECTIVES

This is to identify factors affecting the prevalence of Lactobacillus reuteri in maternal faeces and breast milk and infant faeces after oral supplementation with L reuteri and to assess the influence on microbial ecology, particularly Clostridium difficile and Bifidobacterium colonization.

MATERIALS AND METHODS

In this double-blind trial, 232 mothers with a family history of atopic disease were randomized to a daily intake of either L reuteri American-type culture collection (ATCC) 55730 (1 x 10 colony-forming units [CFU]) or placebo for the last 4 weeks of pregnancy. Their babies then continued with the same study product daily from birth until 12 months of age. Bacterial counts and prevalence were assessed in maternal breast milk and faeces and infant faeces, using conventional cultivation methods.

RESULTS

The prevalence of L reuteri was higher during the first year of life in the stool samples from infants in the active as compared with the placebo-treated group. The highest prevalence was recorded at 5 to 6 days of age (82% in the treated vs 20% in the placebo group, P < 0.001). Lactobacillus reuteri was isolated from 12% and 2%, respectively, in the colostrum samples (P < 0.05). Breast-feeding seemed to reduce faecal L reuteri counts, although antibiotics did not influence the levels of L reuteri. The administration of L reuteri did not affect bifidobacteria or C difficile colonization.

CONCLUSION

Lactobacillus reuteri may be detected in breast milk after oral supplementation to the mother and in almost all infants after oral supplementation during the first year of life, as well as occasionally in many untreated infants.

Probiotics for the treatment of eczema: a systematic review

BACKGROUND

Probiotics have been proposed as a treatment for eczema, but the results of intervention trials have been mixed.

OBJECTIVE

To evaluate the efficacy of probiotics for treating eczema by performing a systematic review of randomized-controlled trials (RCTs).

DESIGN

We searched the Cochrane Skin Group Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, PsycINFO, AMED, LILACS, ISI Web of Science, the reference lists of articles, ongoing clinical trial registers and conference proceedings. RCTs of live orally ingested microorganisms for the treatment of eczema were eligible for inclusion.

RESULTS

Twelve trials (781 participants) were identified. Meta-analysis of data from five of these trials showed that there was no significant reduction in eczema symptoms with probiotic treatment compared with placebo (mean difference -0.90 points on a 20-point visual analogue scale; 95% confidence interval -2.84, 1.04). Meta-analysis of data from seven trials showed no significant difference in investigator rated eczema severity between probiotic and placebo treatments. Subgroup analysis by eczema severity or presence of atopy did not identify a specific population in which probiotic treatment was effective. There was significant heterogeneity between studies; however, the results of three studies that used the same probiotic strain were concordant. The adverse events search identified case reports of sepsis and bowel ischaemia caused by probiotics.

CONCLUSIONS

Currently, probiotics cannot be recommended for treating eczema. The heterogeneity between studies may be attributable to probiotic strain-specific effects, which means that novel probiotic strains may still have a role in eczema management.

Probiotics for preventive health

Gut flora and probiotics have potential to affect health and disease far beyond the gut. There is increasing evidence that probiotics have beneficial effects in preventing a wide range of conditions and improving health. Randomized, double-blind studies have provided evidence of the effectiveness of probiotics for preventing various diarrheal illnesses as well as allergic disorders. Evidence for their efficacy for use in the prevention and treatment of bacterial vaginosis and urinary tract infections is also mounting. In addition, probiotics may be useful for preventing respiratory infections, dental caries, necrotizing enterocolitis, and certain aspects of inflammatory bowel disease. Data also suggest that probiotics may promote good health in day care and work settings, and may enhance growth in healthy as well as ill and malnourished children. Results from meta-analyses and systematic reviews that combine results of studies from different types of probiotics to examine the effects in any disease state should be interpreted with caution. Specific strains are effective in specific disease states. No 2 probiotics are exactly alike; we should not expect reproducible results from studies that employ different species or strains, variable formulations, and diverse dosing schedules.

Scientific rationale for the Finnish Allergy Programme 2008-2018: emphasis on prevention and endorsing tolerance

In similarity to many other western countries, the burden of allergic diseases in Finland is high. Studies worldwide have shown that an environment rich in microbes in early life reduces the subsequent risk of developing allergic diseases. Along with urbanization, such exposure has dramatically reduced, both in terms of diversity and quantity. Continuous stimulation of the immune system by environmental saprophytes via the skin, respiratory tract and gut appears to be necessary for activation of the regulatory network including regulatory T-cells and dendritic cells. Substantial evidence now shows that the balance between allergy and tolerance is dependent on regulatory T-cells. Tolerance induced by allergen-specific regulatory T-cells appears to be the normal immunological response to allergens in non atopic healthy individuals. Healthy subjects have an intact functional allergen-specific regulatory T-cell response, which in allergic subjects is impaired. Evidence on this exists with respect to atopic dermatitis, contact dermatitis, allergic rhinitis and asthma. Restoration of impaired allergen-specific regulatory T-cell response and tolerance induction has furthermore been demonstrated during allergen-specific subcutaneous and sublingual immunotherapy and is crucial for good therapeutic outcome. However, tolerance can also be strengthened unspecifically by simple means, e.g. by consuming farm milk and spending time in nature. Results so far obtained from animal models indicate that it is possible to restore tolerance by administering the allergen in certain circumstances both locally and systemically. It has become increasingly clear that continuous exposure to microbial antigens as well as allergens in foodstuffs and the environment is decisive, and excessive antigen avoidance can be harmful and weaken or even prevent the development of regulatory mechanisms. Success in the Finnish Asthma Programme was an encouraging example of how it is possible to reduce both the costs and morbidity of asthma. The time, in the wake of the Asthma Programme, is now opportune for a national allergy programme, particularly as in the past few years, fundamentally more essential data on tolerance and its mechanisms have been published. In this review, the scientific rationale for the Finnish Allergy Programme 2008-2018 is outlined. The focus is on tolerance and how to endorse tolerance at the population level.

Effects of Bifidobacterium animalis administered during lactation on allergic and autoimmune responses in rodents

Probiotics are promoted as being beneficial to health and positive effects on the immune system have been reported. Beneficial immune effects have been attributed to several mechanisms, including stimulating T helper 1 (Th1) immunity. To explore the effects of the probiotic Bifidobacterium animalis on Th1- and Th2-mediated immune responses, two different animal models representing either Th1- or Th2-mediated immune responses were used: a rat model for experimental autoimmune encephalomyelitis (EAE) (Th1) and a mouse model for respiratory allergy induced by ovalbumin (OVA) (Th2). B. animalis administration started when the mice or rats were 2 weeks old. Respiratory allergy or EAE were induced when the animals were 6-7 weeks old. In the allergy model, B. animalis modestly reduced the number of infiltrating eosinophils and lymphocytes in the lungs, but no effects on allergen-specific serum immunoglobulin E levels were found. Cytokine profiles assessed after culturing spleen cells with the mitogen concanvalin A (ConA) showed that B. animalis skewed the Th1/Th2 balance towards Th1 in females. However, allergen-induced cytokine production in females was not affected by B. animalis. In males, B. animalis significantly decreased ConA-induced interleukin-13 and a trend towards lower levels of OVA-induced Th2 cytokines. In the EAE model, B. animalis significantly reduced the duration of clinical symptoms by almost 2 days in males and improved the body weight gain during the experimental period compared with the control group. Our data show that B. animalis reduced several immune parameters in the allergy as well as in the autoimmunity model.

Oral probiotic control skin inflammation by acting on both effector and regulatory T cells

Probiotics are believed to alleviate allergic and inflammatory skin disorders, but their impact on pathogenic effector T cells remains poorly documented. Here we show that oral treatment with the probiotic bacteria L. casei (DN-114 001) alone alleviates antigen-specific skin inflammation mediated by either protein-specific CD4⁺ T cells or hapten-specific CD8⁺ T cells. In the model of CD8⁺ T cell-mediated skin inflammation, which reproduces allergic contact dermatitis in human, inhibition of skin inflammation by L. casei is not due to impaired priming of hapten-specific IFNγ-producing cytolytic CD8⁺ effector T cells. Alternatively, L. casei treatment reduces the recruitment of CD8⁺ effector T cells into the skin during the elicitation (i.e. symptomatic) phase of CHS. Inhibition of skin inflammation by L. casei requires MHC class II-restricted CD4⁺ T cells but not CD1d-restricted NK-T cells. L casei treatment enhanced the frequency of FoxP3⁺ Treg in the skin and increased the production of IL-10 by CD4⁺CD25⁺ regulatory T cells in skin draining lymph nodes of hapten-sensitized mice. These data demonstrate that orally administered L. casei (DN-114 001) efficiently alleviate T cell-mediated skin inflammation without causing immune suppression, via mechanisms that include control of CD8⁺ effector T cells and involve regulatory CD4⁺ T cells. L. casei (DN-114 001) may thus represent a probiotic of potential interest for immunomodulation of T cell-mediated allergic skin diseases in human.

Complementary and alternative medicine: herbs, phytochemicals and vitamins and their immunologic effects

Complementary and alternative medicines (CAMs) are used in more than 80% of the world's population and are becoming an increasing component of the US health care system, with more than 70% of the population using CAM at least once and annual spending reaching as much as $34 billion. Since the inception of the National Center for Complementary and Alternative Medicine, there has been an enormous increase in the number of basic science and therapy-based clinical trials exploring CAM. The subspecialty of allergy and immunology represents a particularly fertile area with a large number of CAM therapies that have been shown to affect the immune system. Recent work has uncovered potential biochemical mechanisms involved in the immunomodulatory pathway of many supplemental vitamins (A, D, and E) that appear to affect the differentiation of CD4(+) cell T(H)1 and T(H)2 subsets. Other research has shown that herbs such as resveratrol, quercetin, and magnolol may affect transcription factors such as nuclear factor-kappaB and the signal transducer and activator of transcription/Janus kinase pathways with resultant changes in cytokines and inflammatory mediators. Clinically, there have been hundreds of trials looking at the effect of CAM on asthma, allergic rhinitis, and atopic dermatitis. This article reviews the history of CAM and its use among patients, paying special attention to new research focusing on herbals, phytochemicals, and vitamins and their potential interaction with the immune system.

Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects in 2008

This review highlights some of the research advances in anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects and in allergic skin disease that were reported in the Journal in 2008. Key epidemiologic observations include a rise in anaphylaxis in a population-based study and lower rates of peanut allergy in Israel, where infants consume peanut early compared with the United Kingdom, where dietary introduction is generally delayed. Advances in food allergy diagnosis include IgE epitope mapping that discloses the likelihood and severity of allergy; studies correlating likelihood of clinical reactivity on the basis of food-specific IgE to sesame, peanut, milk, and tree nuts; and an observation that a low baseline angiotensin-converting enzyme level may be associated with having pharyngeal edema during a reaction. Molecular, immunologic, and genetic studies are discerning pathways that are key in development of food allergy, identifying new modalities to interrupt mast cell degranulation, and elucidating risks associated with penicillin allergy. Regarding treatment, clinical studies show a majority of children with milk and egg allergy tolerate these proteins in modest amounts when they are extensively heated in baked goods, and studies show promise for oral immunotherapy to treat milk allergy and sublingual immunotherapy for honey bee venom hypersensitivity. The importance of skin barrier dysfunction has continued to be highlighted in the pathophysiology of atopic dermatitis (AD). Research has also continued to identify immunologic defects that contribute to the propensity of patients with AD to develop viral and bacterial infection. New therapeutic approaches to AD, urticaria, and angioedema have been reported including use of probiotics, biologics, vitamin D, and skin barrier creams.

Atopic dermatitis and alternative management strategies

PURPOSE OF REVIEW

To discuss the significance of studies published over the previous year regarding the pathogenesis and treatment of atopic dermatitis, including prevention, skin care, environmental modifications, nutrition, education, and anti-inflammatory medications.

RECENT FINDINGS

Recent evidence shows that 42.5% of the caregivers of children with atopic dermatitis had used alternative therapies, most commonly due to fears of topical steroid side-effects and dissatisfaction with conventional treatment. Common questions, such as the potential utility of prenatal probiotics for prevention of atopic dermatitis, as well as the interplay of food allergies and eczema will be discussed in detail. New research continues to show the efficacy and safety of topical calcineurin inhibitors and atopiclair. We will review advances in the understanding of the pathogenesis of atopic dermatitis, and the latest research on therapies available to clinicians to aid them in discussions with their patients.

SUMMARY

Atopic dermatitis impacts negatively the quality of life of both patients and their families. General pediatricians play a pivotal role in the management of this chronic condition. Management should focus on providing sound advice and easing fears regarding topical steroids, as well as pursuing conservative treatments that have the potential to prevent flares.

Probiotics for the treatment of allergic rhinitis and asthma: systematic review of randomized controlled trials

OBJECTIVE

To evaluate the clinical evidence for the use of probiotics as a therapeutic modality for allergic rhinitis (AR) and asthma.

DATA SOURCES

PubMed was searched to identify randomized controlled trials (RCTs) that studied the effects of probiotics on AR (n = 12) and asthma (n = 4).

STUDY SELECTION

RCTs that studied the effects of probiotics administration on the treatment but not the prevention of AR and asthma were selected for inclusion in this review.

RESULTS

Nine of the 12 RCTs that evaluated clinical outcomes in AR showed an improvement due to the use of probiotics. All the RCTs that studied perennial AR showed lower symptom scoring and medication use with the use of probiotics compared with placebo. Also, 5 of the 8 RCTs that referred to seasonal AR suggested an improvement in clinical outcomes. Nine RCTs that reported various immunologic measurements of allergy found no significant probiotic effects. The RCTs that studied the effect of probiotic administration on the treatment of asthma showed no positive effects.

CONCLUSIONS

Probiotics may have a beneficial effect in AR by reducing symptom severity and medication use. Many more good-quality studies are needed to resolve this issue.

Cellular and molecular mechanisms in atopic dermatitis

Atopic dermatitis (AD) is a pruritic inflammatory skin disease associated with a personal or family history of allergy. The prevalence of AD is on the rise and estimated at approximately 17% in the USA. The fundamental lesion in AD is a defective skin barrier that results in dry itchy skin, and is aggravated by mechanical injury inflicted by scratching. This allows entry of antigens via the skin and creates a milieu that shapes the immune response to these antigens. This review discusses recent advances in our understanding of the abnormal skin barrier in AD, namely abnormalities in epidermal structural proteins, such as filaggrin, mutated in approximately 15% of patients with AD, epidermal lipids, and epidermal proteases and protease inhibitors. The review also dissects, based on information from mouse models of AD, the contributions of the innate and adaptive immune system to the pathogenesis of AD, including the effect of mechanical skin injury on the polarization of skin dendritic cells, mediated by keratinocyte-derived cytokines such as thymic stromal lymphopoietin (TSLP), IL-6, and IL-1, that results in a Th2-dominated immune response with a Th17 component in acute AD skin lesions and the progressive conversion to a Th1-dominated response in chronic AD skin lesions. Finally, we discuss the mechanisms of susceptibility of AD skin lesions to microbial infections and the role of microbial products in exacerbating skin inflammation in AD. Based on this information, we discuss current and future therapy of this common disease.

Strategies for primary prevention of atopy in children

In recent decades, the prevalence of atopic diseases such as asthma, hayfever, food allergy, and atopic dermatitis has been steadily increasing. Unfortunately, more advances have been made in secondary prevention of symptoms and exacerbations than in primary prevention. One barrier to adopting prevention strategies is uncertainty regarding the cause of atopy. A genetic predisposition has been well documented. However, other factors, including diet, environment, infections, medications, and gastrointestinal flora, all play a role in the development of atopic disease. Modifying these factors holds promise for stopping the atopic march in the future. This paper reviews advances that have been made in the primary prevention of atopic disease.

Innate microbial sensors and their relevance to allergy

The innate immune system oversees the gateway to immunity with its microbial sensors. Innate microbial sensors are germ line-encoded receptors with genetically predetermined specificities for microbes. The readiness and effectiveness of the innate immune system to provide immediate and appropriate responses at the host-environment interface is dependent on its sensitive and comprehensive microbial detection systems. The purpose of this review is to provide an overview of innate microbial sensors, our growing understanding of their diverse repertoire, and their elegant structural and functional approaches to microbial recognition. Their relevance to allergic disease is also discussed: the potential recognition and uptake of allergens by some of these receptors, inhibited expression of other microbial sensors by allergic immune responses and inflammation, and their upregulation by microbial exposures in early life that may help to protect against the development of allergic immune responses and disease.