The Human Microbiota and Its Relationship with Allergies

Allergic diseases have been increasing to epidemic proportions during the past century, especially in high-income countries. Recent evidence suggests there might be a link between the allergy epidemic and reduced microbial exposures, resulting from a rapidly evolved modern lifestyle, including changed diets, health and hygiene standards, and daily habits. Recently it has become clear that the microbial communities in our respiratory system and our gut, as well as on our skin, may play a key role in shaping our physiology, and influencing our health. We are only beginning to understand the mechanisms by which the human microbiota may be regulating the immune system, and sudden changes in the composition of the microbiota may have profound effects, linked with an increased risk of developing chronic inflammatory disorders, including allergies.Peer reviewe

Ihon mikrobiomi ja atooppiset taudit

Vertaisarvioitu.Ihmisen ihon ja ihon mikrobiston väliset vuorovaikutukset ovat todennäköisesti keskeisiä tekijöitä ihon terveyden ja sairauden välisessä tasapainossa. Eläinmalleista on opittu, että mikrobien ja isännän väliset vuorovaikutukset iholla ovat merkityksellisiä, varsinkin varhaisella iällä. Monet tutkimustulokset viittaavat myös siihen, että monimuotoinen mikrobisto tukee terveen immuunipuolustuksen kehittymistä. Uusien lääketieteellisten hoitojen kehittämisen kannalta on tärkeää, että tiedetään enemmän mekanismeista, jotka johtavat immuunijärjestelmän ja ihmisen mikrobiston välisen terveyttä edistävän symbioosin muodostumiseen. Nykyiset kokeelliset ja kliiniset tutkimustulokset tukevat iholla luonnollisesti elävien bakteerien käyttöä atooppisen ihottuman hoidossa. Tutkimustulokset ovat kuitenkin vielä alustavia, eikä vielä tiedetä, miten turvallisia nämä bakteerit ovat ja miten ne vaikuttavat ihon mikrobistoon.Peer reviewe

The role of soil exposure in asthma prevention during neonatal period Reply

Non peer reviewe

Holistic view on health : two protective layers of biodiversity

The western world has witnessed a rising epidemic of chronic inflammatory disorders, such as allergies and asthma. This epidemic is expected to spread also to the rest of the world, where allergies have to date been practically absent, along with adoption of western lifestyle. In parallel, biological diversity is globally declining. This inspired Ilkka Hanski, together with medical doctors, to formulate the biodiversity hypothesis of allergic disease. This hypothesis proposes that reduced contact with natural environments, including natural microbial diversity, is associated with unhealthy human microbiota, less able to educate the immune system. Contact with beneficial bacteria, particularly early in life, seems to be instrumental to the normal development of immune responses. Changes in lifestyle and diet, destruction of natural environments, and urbanisation threaten our natural exposure to these beneficial bacteria and thus also reduce their impact on our physiology. To ensure a healthy life, we need to preserve biodiversity in the environment and make sure it finds a favourable home in us. In this review, we will focus on the role of commensal microbiota in human health and wellbeing, as well as the interaction between our microbiota and environmental microbiota, highlighting the contribution of Ilkka Hanski.Peer reviewe

CD8+T Cell Migration to the Skin Requires CD4+Help in a Murine Model of Contact Hypersensitivity

Peer reviewe

A Randomized, Open-Label Trial of Hen's Egg Oral Immunotherapy : Efficacy and Humoral Immune Responses in 50 Children

BACKGROUND: Egg allergy is the second most common food allergy in children. Persistent food allergy increases the risk of anaphylaxis and reduces the quality of life. OBJECTIVE: To determine the efficacy of oral immunotherapy (OIT) with raw egg white powder and study its effects on humoral responses in children with persistent egg allergy. METHODS: Fifty children aged 6 to 17 years with egg allergy, diagnosed by double-blind, placebo-controlled food challenge, were randomized 3:2 to 8 months of OIT with a maintenance dose of 1 g of egg white protein or 6 months of avoidance after which the avoidance group crossed over to OIT. We examined changes in IgE, IgG4, and IgA concentrations to Gal d 1-4 during OIT compared with avoidance and assessed clinical reactivity at 8 and 18 months. RESULTS: After 8 months, 22 of 50 children (44%) on OIT and 1 of 21 (4.8%) on egg avoidance were desensitized to the target dose, 23 of 50 (46%) were partially desensitized (dosePeer reviewe

Complex 2B4 Regulation of Mast Cells and Eosinophils in Murine Allergic Inflammation

The cell surface molecule 2B4 (CD244) is an important regulator of lymphocyte activation, and its role in antiviral immunity and lymphoproliferative disorders is well established. Although it is also expressed on mast cells (MCs) and eosinophils (Eos), the functions of 2B4 on these allergy-orchestrating cells remain unclear. We therefore investigated the role of 2B4 on murine MCs and Eos, particularly how this molecule affects allergic and nonallergic inflammatory processes involving these effector cells. Experiments in bone marrow–derived cultures revealed an inhibitory effect for 2B4 in MC degranulation, but also an opposing stimulatory effect in eosinophil migration and delayed activation. Murine disease models supported the dual 2B4 function: In 2B4-/- mice with nonallergic peritonitis and mild atopic dermatitis (AD), modest infiltrates of Eos into the peritoneum and skin (respectively) confirmed that 2B4 boosts eosinophil trafficking. In a chronic AD model, 2B4-/- mice showed overdegranulated MCs, confirming the inhibiting 2B4 effect on MC activation. This multifunctional 2B4 profile unfolded in inflammation resembles a similar mixed effect of 2B4 in natural killer cells. Taken together, our findings provide evidence for physiological 2B4 stimulatory/inhibitory effects in MCs and Eos, pointing to a complex role for 2B4 in allergy

Integrative transcriptome analysis deciphers mechanisms of nickel contact dermatitis

Background Nickel-induced allergic contact dermatitis (nACD) remains a major occupational skin disorder, significantly impacting the quality of life of suffering patients. Complex cellular compositional changes and associated immunological pathways are partly resolved in humans; thus, the impact of nACD on human skin needs to be further elucidated. Methods To decipher involved immunological players and pathways, human skin biopsies were taken at 0, 2, 48, and 96 hours after nickel patch test in six nickel-allergic patients. Gene expression profiles were analyzed via microarray. Results Leukocyte deconvolution of nACD-affected skin identified major leukocyte compositional changes at 48 and 96 hours, including natural killer (NK) cells, macrophage polarization, and T-cell immunity. Gene set enrichment analysis mirrored cellular-linked functional pathways enriched over time. NK cell infiltration and cytotoxic pathways were uniquely found in nACD-affected skin compared to sodium lauryl sulfate-induced irritant skin reactions. Conclusion These results highlight key immunological leukocyte subsets as well as associated pathways in nACD, providing insights into pathophysiology with the potential to unravel novel therapeutic targets.Peer reviewe