Epidemiology of atopic dermatitis and atopic march in children

Elf3 regulates allergic airway inflammation by controlling dendritic cell-driven T cell differentiation

Elf3 belongs to the Ets family of transcription factors and has been implicated in inflammation. Elf3 is highly expressed in the lungs, and Elf3(-/-) mice are impaired in IL-6 production after intranasal LPS exposure. To identify the role of Elf3 in Th17-driven pulmonary inflammation, we have performed epicutaneous sensitization of Elf3(-/-) mice with OVA followed by airway OVA challenge and have identified Elf3(-/-) mice to be impaired in induction of Th17 response, attributable to impairment of IL-6 production by dendritic cells (DCs). However, increased serum levels of OVA-specific IgG1 and IgE were observed, pointing toward an exaggerated Th2 response. To study Th2 response, we performed i.p. sensitization of Elf3(-/-) mice with OVA and confirmed loss of Elf3 to result in an aggravated Th2 response, characterized by increased generation of IL-4-producing T cells, increased levels of OVA-specific IgE and IgG1 Ab titers, and increased serum levels of Th2 cytokines, together with extensive inflammation and mucus production in airways. Elf3(-/-) DCs were impaired in priming Th1 differentiation, which, in turn, promoted Th2 differentiation. This was mediated by the ability of Elf3(-/-) DCs to undergo hypermaturation but secrete significantly lower levels of IL-12 in response to inflammatory stimuli. The impairment of IL-12 production was due to impairment of IL-12p40 gene induction in Elf3(-/-) DCs in response to inflammatory stimuli. Taken together, our study identifies a novel function of Elf3 in regulating allergic airway inflammation by regulating DC-driven Th1, Th2, and Th17 differentiation.

The allergic march: can we prevent allergies and asthma?

The allergic march is a progression of atopic disease from eczema to asthma, and then to allergic rhinoconjunctivitis. It appears to be caused by a regional allergic response with breakdown of the local epithelial barrier that initiates systemic allergic inflammation. Genetic and environmental factors predispose to developing the allergic march. There are data to support 4 possible interventions to prevent the allergic march from progressing to asthma: (1) supplements of dietary probiotics, (2) exclusive breast feeding during the first few months of life, or, alternatively (3) use of extensively hydrolyzed infant formulas, (4) treatment with inhalant allergen immunotherapy by either subcutaneous or sublingual methods.

Recent research and developmental strategy of anti-asthma drugs

Extensive research over the past decade has provided information about the pharmacotherapy of bronchial asthma (BA). Anti-asthma drugs are classified into two categories: relievers (for the relief of asthma attack symptoms) and controllers (for the prevention of asthma symptoms). This paper aims to review the recent advancements of anti-asthma drugs that are controller medicines. The controllers mainly act on immune and inflammatory responses in BA development. 1) Immunomodulators. Drugs that act on the immune response are classified into two categories: immunosuppressors and immunomodulators, including immunopotentiators. The immunomodulation of the Th1 and Th2 imbalance is the first strategy of the controller because allergic BA is thought to be caused by Th2-polarized immunity. Suplatast is a novel immunomodulator that can adjust the imbalance in the Th1/Th2 immune response and shows clear clinical efficacy against BA. The immunomodulator approach has shifted from a more theoretical and conceptual model to one supported by evidence of clinical efficacy.2) Anti-inflammatory agents. Corticosteroids,mast cell stabilizers and autacoid inhibitors are anti-inflammatory agents for BA. The clinical superiority of the combined therapy of inhaled corticosteroids and long-acting beta2 agonists is evident. This combined therapy shows a potent synergic anti-inflammatory effect compared to the effect by corticosteroids alone. Currently, the anti-inflammatory agents for BA under development are drugs affecting lipid mediators. The prostaglandin (PG) D2 antagonist, PGE2, EP3 agonist and PGI2 agonist are being considered in addition to well-established leukotriene and thromboxane A2 inhibitors. New development strategies and therapeutics for controllers are described in this review.

Quality of life in infants with atopic dermatitis and healthy infants: a follow-up from birth to 24 months

AIM

To evaluate quality of life (QOL) in infants with atopic dermatitis (AD) by comparison with healthy infants to find treatment modalities contributing most to QOL in these patients.

METHODS

The population (N=134) was recruited in the context of an on-going prospective mother-infant study. QOL was measured using the Infant Dermatitis Quality of Life Index for the infants with AD and a modification of this for the healthy infants.

RESULTS

The index scores of infants with AD were 4.15 (SD 2.96), 3.89 (SD 3.62) and 3.23 (SD 2.71) at 6, 12 and 24 months, respectively, the QOL being significantly poorer at 6 (p<0.001) and 12 (p=0.01) months compared to healthy infants. The principal impairments were itching, scratching and sleep disturbances at 6 and 12 months and treatment difficulties at 6 months. Problems with getting to sleep were reported at all stages irrespective of AD.

CONCLUSIONS

Simple treatment regimens targeting itching in particular are likely to contribute most to the QOL of infants with AD; however, sleeping problems may remain as an age-related phenomenon. Early detection of symptoms and effective parent guidance contributed to the well-being of the child.

Epidemiology of allergy

Atopic disease represents a spectrum of disorders characterized by abnormal sensitivity mediated by IgE; approximately 20% of Americans suffer from some form of allergic disease. The sequelae of inhalant and food allergies may present in many organ systems. Manifestations of allergic disease in one site are often associated with symptoms from another site. It is important for clinicians to understand the epidemiology of atopic disease and its causes to facilitate implementation of effective treatment and prevention strategies. This review focuses on the epidemiology of inhalant allergies causing allergic rhinitis and asthma and on IgE-mediated food allergies.

Barrier dysfunction caused by environmental proteases in the pathogenesis of allergic diseases

Skin barrier dysfunction has emerged as a critical driving force in the initiation and exacerbation of atopic dermatitis and the "atopic march" in allergic diseases. The genetically determined barrier deficiency and barrier disruption by environmental and endogenous proteases in skin and epithelium are considered to increase the risk of sensitization to allergens and contribute to the exacerbation of allergic diseases. Sources of allergens such as mites, cockroaches, fungi, and pollen, produce or contain proteases, which are frequently themselves allergens. Staphylococcus aureus, which heavily colonizes the lesions of atopic dermatitis patients and is known to trigger a worsening of the disease, also produces extracellular proteases. Environmental proteases can cause barrier breakdown in the skin, not only in the epithelium, and stimulate various types of cells through IgE-independent mechanisms. Endogenous protease inhibitors control the functions of environmental and endogenous proteases. In this review, we focus on the barrier dysfunction caused by environmental proteases and roles of endogenous protease inhibitors in the pathogenesis of allergic diseases. Additionally, we examine the subsequent innate response to Th2-skewed adaptive immune reactions.

The atopic march: progression from atopic dermatitis to allergic rhinitis and asthma

Atopic dermatitis (AD) is an inflammatory disease characterized by pruritic skin lesions. The pathogenesis of AD may include disrupted epidermal barrier function, immunodysregulation, and IgE-mediated sensitization to food and environmental allergens. AD is also part of a process called the atopic march, a progression from AD to allergic rhinitis and asthma. This has been supported by multiple cross-sectional and longitudinal studies and experimental data. Research on the mechanisms of AD has been centered on the adaptive immune system with an emphasis on the T-helper 1 (Th1)-Th2 paradigm. Recently, the conceptual focus has largely shifted to include a primary defect in the epithelial barrier as an initial event in AD providing a significant insight into the disease initiation and pointing to a complex secondary interplay of environmental and immunological sequelae with barrier disruption. Further understanding of AD will help the development of more effective treatment for AD and ultimately, preventative algorithms for the atopic march. In this review we highlight recent advances in our understanding of the pathogenesis of AD and the atopic march.

IL-10 controls Th2-type cytokine production and eosinophil infiltration in a mouse model of allergic airway inflammation

Interleukin-10 was originally described as a factor that inhibits cytokine production by murine Th1 clones. Recent studies have since shown that IL-10 can also downregulate Th2 clones and their production of IL-4 and IL-5. Because of its immuno-suppressive properties, IL-10 has been suggested as a potential therapy for allergic inflammation and asthma. However, the pathophysiological role of IL-10 in vivo has not been clearly elucidated. We investigated the effects of IL-10 administration on the production of IgE, cytokine and allergen-induced Th2 cytokine production as well as its effects on eosinophilic inflammation. We established GATA-3/TCR double transgenic (GATA-3/TCR-Tg) mice by crossing GATA-3 transgenic mice with ovalbumin (OVA)-specific TCR transgenic mice; these mice were then sensitized using an intraperitoneal injection of OVA adsorbed to alum and challenged with the intratracheal instillation of an allergen. When GATA-3/TCR-Tg mice sensitized with OVA and alum were injected with C57-IL-10 cells before OVA inhalation, the levels of IL-5, IL-13, and IL-4 decreased by 40-85% and number of eosinophils decreased by 70% (P<0.03) in the murine bronchoalveolar lavage fluid (BALF). These results suggest that IL-10 plays an important role downstream of the inflammatory cascade in the Th2 response to antigens and in the development of BALF eosinophilia and cytokine production in a murine model of asthma. These immunosuppressive properties in animal models indicate that IL-10 could be a potential clinical therapy for the treatment of allergic inflammation.