Brief case series: montelukast, at doses recommended for asthma treatment, reduces disease severity and increases soluble CD14 in children with atopic dermatitis

Cysteinyl leukotriene E4 activates human group 2 innate lymphoid cells and enhances the effect of prostaglandin D2 and epithelial cytokines

Background

Group 2 innate lymphoid cells (ILC2s) are a potential innate source of type 2 cytokines in the pathogenesis of allergic conditions. Epithelial cytokines (IL-33, IL-25, and thymic stromal lymphopoietin [TSLP]) and mast cell mediators (prostaglandin D₂ [PGD₂]) are critical activators of ILC2s. Cysteinyl leukotrienes (cysLTs), including leukotriene (LT) C₄, LTD₄, and LTE₄, are metabolites of arachidonic acid and mediate inflammatory responses. Their role in human ILC2s is still poorly understood.

Objectives

We sought to determine the role of cysLTs and their relationship with other ILC2 stimulators in the activation of human ILC2s.

Methods

For ex vivo studies, fresh blood from patients with atopic dermatitis and healthy control subjects was analyzed with flow cytometry. For in vitro studies, ILC2s were isolated and cultured. The effects of cysLTs, PGD₂, IL-33, IL-25, TSLP, and IL-2 alone or in combination on ILC2s were defined by using chemotaxis, apoptosis, ELISA, Luminex, quantitative RT-PCR, and flow cytometric assays. The effect of endogenous cysLTs was assessed by using human mast cell supernatants.

Results

Human ILC2s expressed the LT receptor CysLT₁, levels of which were increased in atopic subjects. CysLTs, particularly LTE₄, induced migration, reduced apoptosis, and promoted cytokine production in human ILC2s in vitro. LTE₄ enhanced the effect of PGD₂, IL-25, IL-33, and TSLP, resulting in increased production of type 2 and other proinflammatory cytokines. The effect of LTE₄ was inhibited by montelukast, a CysLT₁ antagonist. Interestingly, addition of IL-2 to LTE₄ and epithelial cytokines significantly amplified ILC2 activation and upregulated expression of the receptors for IL-33 and IL-25.

Conclusion

CysLTs, particularly LTE₄, are important contributors to the triggering of human ILC2s in inflammatory responses, particularly when combined with other ILC2 activators.

A Double-Blind, Randomized, Crossover Study to Compare the Effectiveness of Montelukast on Atopic Dermatitis in Korean Children

PURPOSE

Some studies report a role of leukotrienes in the pathogenesis of atopic dermatitis and suggest a rationale for the use of leukotriene receptor antagonist (LTRA) in the treatment of atopic dermatitis. This study aimed to evaluate the treatment effectiveness of montelukast in children with atopic dermatitis.

METHODS

Fifty-four children between the ages of 2 and 6 years with moderate to severe atopic dermatitis were enrolled. Group A received montelukast for 8 weeks, followed by a crossover to 8 weeks of placebo after a 2-week washout period. Group B reversed the administration according to a randomized, double-blind, placebo-controlled, crossover design. The SCORing atopic dermatitis (SCORAD) index, urinary leukotriene E₄ (LTE₄), and eosinophil-derived neurotoxin (EDN) were assessed at every visit.

RESULTS

Forty-three patients (21 males) completed the study. Although the SCORAD index was decreased in both groups, there was no statistically significant difference between montelukast and placebo (-3.0±11.2 vs -5.7±11.3, P=0.43). The level of urinary LTE₄ was decreased after taking montelukast when compared to placebo, but there was no statistically significant difference (-65.9±556.2 vs 87.7±618.3, P=0.26). The changes in urinary EDN after taking montelukast and placebo had no significant difference (37.0±1,008.6 vs -195.8±916.7, P=0.10). When analyzing SCORAD indices, urinary LTE₄, and EDN, we could not prove the effectiveness of montelukast in the atopic, non-atopic or high ECP (ECP ≥15 μg/L) subgroups.

CONCLUSIONS

There was no statistically significant difference in clinical improvement or biomarkers between montelukast and placebo treatment. Therefore, conventional treatments with skin care and infection control might be more important strategies in the treatment of atopic dermatitis.

Systemic therapy of childhood atopic dermatitis

Atopic dermatitis (AD) is a common childhood inflammatory disease that, in a small percentage of cases, can become severe enough to require potent systemic treatment. Many trials have been conducted with systemic agents for the treatment of severe pediatric AD; we review the evidence here. Although corticosteroids are widely used in practice, they are not generally recommended as a systemic treatment option for AD in children. Most patients experience a relatively rapid and robust response to cyclosporine. Treating children with cyclosporine long term is troubling; however, azathioprine, mycophenolate mofetil, and methotrexate are all reasonable alternatives for maintenance therapy in recalcitrant cases. Several additional options are available for the most refractory cases, including interferon-γ, intravenous immunoglobulin, and various biologics. Phototherapy is another modality that can be effective in treating severe AD. Ultimately the choice of agent is individualized. Systemic therapy options are associated with potentially severe adverse effects and require careful monitoring. Nonsystemic approaches toward prevention of flares and long-term control of atopic dermatitis in pediatric patients should be continued in conjunction with systemic therapy. In the future, more targeted systemic treatments hold the potential for effective control of disease with fewer side effects than broadly immunosuppressive agents.

Clinical effectiveness and safety of montelukast in asthma. What are the conclusions from clinical trials and meta-analyses?

Asthma is a common childhood atopic disease associated with chronicity and impaired quality of life. As there is no cure for this disease, treatment relies on avoidance of triggers such as food and aeroallergens, the use of inhaled bronchodilators/corticosteroids and antiallergic or immunomodulating therapies. Inhaled corticosteroids (ICSs) and bronchodilators have been the mainstay. However, in Asia, myths and fallacies regarding Western medicine and corticosteroids are prevalent and lead to nonadherence to treatment. Also, use of traditional and proprietary herbal medicines is popular. In the past decades, a novel class of nonsteroidal immunomodulating montelukasts has become available. This article reviews the evidence for the effectiveness and clinical efficacy of these medications. A number of randomized and controlled trials have been performed over the years. The majority of studies confirm the usefulness of montelukast as monotherapy and add-on therapy to ICS in mild to moderate childhood asthma across all age groups. ICSs are generally superior to montelukasts for asthma management. However, montelukast has a place in the treatment of young children with viral-triggered wheezing diseases, exercise-induced asthma, and in children whose parents are steroid-phobic and find ICS unacceptable.

Therapeutic Hotline: Cysteinyl leukotriene receptor antagonist montelukast in the treatment of atopic dermatitis

Leukotrienes are potent proinflammatory mediators derived from arachidonic acid through the 5-lipoxygenase pathway. Experimental data suggest a role for cysteinyl leukotrienes in the pathogenesis of atopy giving a rationale for its use in asthma, allergic rhinitis, and chronic urticaria management. A few clinical observations and small trials suggest that montelukast may be used in an adjunctive manner as an effective therapeutic option for all age categories affected by moderate-to-severe atopic dermatitis. Our own observations proved that montelukast as a prospective corticosteroid-sparing option in the complex therapeutic strategy of corticosteroid-dependent atopic dermatitis patients, even in the severe erythrodermic cases.

Leukotriene inhibition in small animal medicine

Leukotrienes are important mediators of inflammatory and allergic conditions in people and are suspected to play an important role in tumorigenesis and tumor growth of several different tumor types. Based on this, researchers are making great progress in identifying novel pharmacologic targets for several human diseases. Leukotriene inhibition has resulted in therapeutic benefit in clinical trials involving people with osteoarthritis, allergic asthma, and atopic dermatitis. Despite this progress and the possibility that leukotriene inhibition may also play an important therapeutic role in veterinary patients, parallel advances have not yet been made in veterinary medicine. This article summarizes leukotriene function and synthesis. It also reviews the published literature regarding potential therapeutic applications of leukotriene inhibition in both human and veterinary medicine, focusing primarily on osteoarthritis, NSAID induced gastrointestinal mucosal damage, allergic asthma, atopic dermatitis, and cancer.

Does age or gender influence quality of life in children with atopic dermatitis?

BACKGROUND

Quality of life (QoL) is impaired in children with atopic dermatitis (AD) but the various aspects of QoL may not be equally affected. Aim. To evaluate if age and gender affect some aspects of QoL in children with AD.

METHOD

The Children's Dermatology Life Quality Index (CDLQI) was used for all children with AD seen at a paediatric dermatology clinic over a 3-year period. Disease severity was assessed using the SCORing Atopic Dermatitis (SCORAD) and Nottingham Eczema Severity Score (NESS) tools.

RESULTS

We reviewed CDLQI in 133 children (70 male and 63 female; age range 5-16 years) with AD. Itch, sleep disturbance, treatment and swimming/sports were the four aspects of QoL issues that were most commonly affected, in 50%, 47%, 38% and 29% of patients, respectively. Problems with interpersonal issues (friendship, school/holidays, and teasing/bullying) occurred in only a minority of children (<or= 10%). Girls had more problems with issues of clothes and shoes than did boys (OR = 2.86, 95% CI 1.05-8.00; P = 0.038). Significant itch and sleep disturbance affected both genders similarly but were generally more common in children <or= 10 years (itch: OR = 2.31, 95% CI 1.04-5.14; P = 0.039; and sleep: OR = 2.31, 95% CI 1.05-5.13; P = 0.037).

CONCLUSIONS

Not all aspects of QoL are affected equally in children with AD. The disease seems to affect personal domains of itch and sleep more than the interpersonal issues. Age and gender are relevant factors in QoL, with the issue of clothes/shoes being more troublesome for girls. itch and sleep disturbance seem to be a problem mainly in younger children.

Emerging treatment of atopic dermatitis

Atopic dermatitis is a chronically relapsing eczematous disease of the skin. A wide range of therapeutic regimens has been used for atopic dermatitis. A better understanding of its pathogenesis will also lead to the development of novel approaches to treating this disease. This article reviews the recent advances in allergen-specific sublingual immunotherapy and therapy with antileukotriene drugs, probiotics, mycophenolate mofetil, leflunomide, and intermittent fluticasone propionate ointment, which the authors expect will be clinically useful therapies in the near future.

Cysteinyl-leukotrienes and their receptors in asthma and other inflammatory diseases: critical update and emerging trends

Cysteinyl-leukotrienes (cysteinyl-LTs), that is, LTC4, LTD4, and LTE4, trigger contractile and inflammatory responses through the specific interaction with G protein-coupled receptors (GPCRs) belonging to the purine receptor cluster of the rhodopsin family, and identified as CysLT receptors (CysLTRs). Cysteinyl-LTs have a clear role in pathophysiological conditions such as asthma and allergic rhinitis (AR), and have been implicated in other inflammatory conditions including cardiovascular diseases, cancer, atopic dermatitis, and urticaria. Molecular cloning of human CysLT1R and CysLT2R subtypes has confirmed most of the previous pharmacological characterization and identified distinct expression patterns only partially overlapping. Interestingly, recent data provide evidence for the immunomodulation of CysLTR expression, the existence of additional receptor subtypes, and of an intracellular pool of CysLTRs that may have roles different from those of plasma membrane receptors. Furthermore, genetic variants have been identified for the CysLTRs that may interact to confer risk for atopy. Finally, a crosstalk between the cysteinyl-LT and the purine systems is being delineated. This review will summarize and attempt to integrate recent data derived from studies on the molecular pharmacology and pharmacogenetics of CysLTRs, and will consider the therapeutic opportunities arising from the new roles suggested for cysteinyl-LTs and their receptors.

Atopic dermatitis

Atopic dermatitis is an especially common and frustrating condition, and the prevalence is increasing. The disease can adversely affect the quality of life of patients and caregivers. Significant advances in our understanding of the pathogenesis have led to improvements in therapy. Patient and caregiver education, avoidance of potential triggering factors, optimal skin care, and pharmacotherapy offer the potential for good control for most patients.

Atopic eczema: what's new?

Atopic eczema (AE) is a chronic inflammatory skin disease characterized by recurrent intense pruritus and a typical age-related distribution of skin lesions. Several new aspects with regard to the pathogenetic background as well as strategies for prevention, diagnosis and treatment of AE have emerged. There are ongoing studies on genetic susceptibility loci, as well as environmental and nutritional factors associated with an increase or a decrease of AE lesions. The atopy patch test is now available for identification of allergens in aeroallergen-triggered AE. New topical therapies, such as the calcineurin inhibitors, have broadened the therapeutic armamentarium substantially. In order to increase knowledge and coping strategies, patient education programs have been launched. Learning objective Upon completing this paper, the reader should be aware of new developments in AE, especially on nomenclature, prevention strategies, diagnostic tests, as well as therapeutic options.