Alternative agents in asthma

Cyclosporin A indirectly attenuates activation of group 2 innate lymphoid cells in papain-induced lung inflammation

Cyclosporin A (CsA) is a well-known immunosuppressant that is used against steroid-resistant asthma. Group 2 innate lymphoid cells (ILC2s) and type 2 helper T (Th2) cells produce Th2 cytokines including IL-5 and play important roles in asthma pathogenesis. Here, we studied the effects of CsA in allergen-induced lung inflammation in mice and found that CsA decreased the number of lung ILC2s and attenuated papain-induced activation of ILC2s accompanied with IL-5 expression. The ILC2 suppression mediated by CsA was not observed in culture or in lymphocyte-deficient Rag2^-/- mice. Thus, we propose a new suppressive effect of CsA, i.e., administration of CsA indirectly suppresses maintenance and activation of lung ILC2s in addition to direct suppression of T-cell activation and cytokine production.

Current treatment of severe asthma

Severe asthma is considered a heterogeneous disease in which a variety of clinical, physiological and inflammatory markers determine disease severity. Pivotal studies in the last 5 years have led to substantial progress in many areas, ranging from a more accurate definition of truly severe, refractory asthma, to classification of the disease into distinct clinical phenotypes, and introduction of new therapies. This review focuses on three common clinical phenotypes of severe asthma in adults (early onset severe allergic asthma, late onset non-atopic eosinophilic asthma, late onset non-eosinophilic asthma with obesity), and provides an overview of recent developments regarding treatment options that are best suited for each of these phenotypes.

Pathophysiology of allergic inflammation

Allergic inflammation is due to a complex interplay between several inflammatory cells, including mast cells, basophils, lymphocytes, dendritic cells, eosinophils, and sometimes neutrophils. These cells produce multiple inflammatory mediators, including lipids, purines, cytokines, chemokines, and reactive oxygen species. Allergic inflammation affects target cells, such as epithelial cells, fibroblasts, vascular cells, and airway smooth muscle cells, which become an important source of inflammatory mediators. Sensory nerves are sensitized and activated during allergic inflammation and produce symptoms. Allergic inflammatory responses are orchestrated by several transcription factors, particularly NF-κB and GATA3. Inflammatory genes are also regulated by epigenetic mechanisms, including DNA methylation and histone modifications. There are several endogenous anti-inflammatory mechanisms, including anti-inflammatory lipids and cytokines, which may be defective in allergic disease, thus amplifying and perpetuating the inflammation. Better understanding of the pathophysiology of allergic inflammation has identified new therapeutic targets but developing effective novel therapies has been challenging. Corticosteroids are highly effective with a broad spectrum of anti-inflammatory effects, including epigenetic modulation of the inflammatory response and suppression of GATA3.

Use of inhaled and oral corticosteroids and the long-term risk of cataract

OBJECTIVE

Longitudinal associations between inhaled and oral corticosteroid use and 10-year incident cataract were examined.

DESIGN

Population-based cohort study.

PARTICIPANTS

The Blue Mountains Eye Study examined 3654 Australians aged 49 years or older (1992-1994); 2335 were re-examined after 5 years and 1952 were re-examined after 10 years (75.1%, 75.6% of survivors, respectively).

METHODS

Questionnaires were used to assess inhaled and oral corticosteroid use at baseline. Past users were participants who had used these medications for at least 1 month in the past but were not using them at baseline. Current users were those who were using these medications at baseline and had been doing so for at least 1 month. Ever users combined past and current users.

MAIN OUTCOME MEASURES

Lens photographs were obtained at each examination and graded for nuclear, cortical, and posterior subcapsular (PSC) cataracts following the Wisconsin Cataract Grading System. Participants without a specific subtype of cataract in either eye at baseline were considered to be at risk of that type of cataract developing over the 10-year follow-up. Incidence of each cataract subtype in this report refers to person-specific, first-eye incidence.

RESULTS

At baseline, 103 participants were current and 120 past users of inhaled corticosteroids, and 31 were current and 147 were past users of oral corticosteroids. Current users had a greater risk of developing PSC cataract after adjustment for age and gender (inhaled: odds ratio [OR] 2.50, 95% confidence interval [CI] 1.33-4.69; oral: OR 4.11; 95% CI 1.67-10.08) and nuclear cataract (inhaled: OR 2.04, 95% CI 1.21-3.43; oral: OR 3.45, 95% CI 1.26-9.43) but not cortical cataract. Interaction between inhaled and oral corticosteroid use was significant for PSC (P = 0.01) and nuclear (P = 0.02) cataract incidence. In subgroup analyses, only individuals who used both inhaled and oral steroids were at increased risk of PSC cataract (after adjusting for age, sex, smoking, hypertension, diabetes, and education levels; OR 4.76, 95% CI 2.59-8.74), comparing ever users of both with users of neither.

CONCLUSIONS

High long-term risks of PSC and nuclear cataract development were found for users of combined inhaled and oral corticosteroids.

Use of omalizumab in a severe asthma clinic

There is an urgent need to define new treatment strategies for severe persistent asthma. Using a severe asthma clinic model, it is possible to systematically assess diagnosis, self-management skills, and treatment efficacy. The addition of single-patient trials of therapy is useful to detect individual responders to drugs where use is limited because of access, cost, or toxicity. Omalizumab is effective in severe asthma, however access is restricted by cost and availability. We conducted single patient efficacy trials of omalizumab in 12 subjects with severe refractory asthma. There were 2 definite and 6 partial responders. Patients with difficult/therapy resistant or refractory asthma can respond to omalizumab, and this response can be detected in individual patients using a single patient controlled trial conducted in the setting of a severe asthma clinic.

Oral corticosteroid-dependent asthma: a 30-year review

OBJECTIVE

To identify novel aspects of the pathogenesis, therapeutic options, and prophylaxis measures of corticosteroid-dependent asthma.

DATA SOURCES

PubMed searches were undertaken of studies published between 1966 and 2006 on the pathogenesis of and corticosteroid-sparing therapies for corticosteroid-dependent asthma. Identified review articles were surveyed for additional and earlier citations. Recent American Academy of Asthma, Allergy, and Immunology meeting abstracts were also searched to identify other recently published and unpublished studies.

STUDY SELECTION

Inclusion of studies in the review was decided by simple agreement of both reviewers, who independently read the "Methods" and "Discussion" sections of articles identified using the search strategy. Quality assessment was performed by the 2 reviewers.

RESULTS

High-dose inhaled corticosteroids are the first-line option for corticosteroid-dependent asthmatic patients with clear efficacy. Omalizumab is effective in reducing oral corticosteroid requirements in allergic asthma. Methotrexate, gold, and cyclosporine have corticosteroid-sparing effects clinically that must be weighed against a serious adverse effect profile. Nebulized diuretics and lidocaine, with a low adverse effect profile, offer promising results but require further study. Clarithromycin and telithromycin seem to have an independent mechanism of inflammatory modulation, but their effect on corticosteroid-dependent asthma remains to be seen. Etanercept offers only early clinical evidence of a role in corticosteroid-dependent asthma.

CONCLUSIONS

With no clear consensus on corticosteroid-sparing treatment in corticosteroid-dependent asthmatic patients, systemic glucocorticoids remain the foremost therapy, with adverse effects that require monitoring and prophylaxis.

Efficacy and safety of modified Mai-Men-Dong-Tang for treatment of allergic asthma

The aim of this study was to evaluate the efficacy and safety of a Chinese herbal formula modified Mai-Men-Dong-Tang (mMMDT) for treatment of persistent, mild-to-moderate asthma. A total of 100 asthmatic patients were enrolled and assigned to three treatment groups in this double-blind, randomized, placebo-controlled clinical trial. Over a period of 4 months, patients in groups A and B received 80 and 40 mg/kg/day of mMMDT, while those in group C received a placebo. Efficacy variables included changes in forced expiratory volume in 1 s (FEV1), symptom score, serum total immunoglobulin E (IgE), and dust mite-specific IgE. Safety assessments included complete blood count, and liver and kidney function. Relative to baseline, significantly greater increases in FEV1 were demonstrated for both A and B groups in comparison with the placebo-treated analog (both p <0.05). Further, similar improvements in symptom score were observed for both mMMDT treatment groups. The serum total IgE for group A showed a decreasing tendency after treatment but no statistical difference was noted. Furthermore, no drug-related adverse effects were reported. Blood test, and liver and kidney function were within normal range during the study, with no marked changes demonstrated over time. In conclusion, the Chinese herbal formula mMMDT provided improvements in lung function and relieved asthma symptoms in our sample of patients. Given its efficacy and safety, we consider mMMDT a credible treatment regimen for persistent, mild-to-moderate asthma.

Resolution of late-onset asthma following high-dose chemotherapy

We describe a patient with moderately severe (British Thorax Society Step IV/V) asthma requiring regular inhaled and oral corticosteroids to control symptoms who experienced resolution of her asthma following high-dose chemotherapy and autologous stem cell transplantation for breast cancer. As far as the authors are aware this is the first reported case.

Role of intravenous immunoglobulin in severe steroid-dependent asthma

BACKGROUND

Subgroups of asthma patients have extremely severe respiratory symptoms that require chronic use of steroids for disease control. These patients are at risk of significant side-effects from chronic exposure to high doses of oral steroids. Intravenous immunoglobulin (IVIG) has immunomodulatory properties as shown by its use in some immune disorders. A few trials have suggested a possible benefit in individuals with severe asthma.

AIMS

To evaluate the role of IVIG as an adjunctive therapy in steroid-dependent asthma, monitoring the outcomes of lung function and measured reduction in oral steroid requirement.

METHOD

Seven patients with severe steroid-dependent asthma were given IVIG at a dose of 1 g/kg each month for 6 months. Baseline pulmonary function tests and immunoglobulin levels were obtained. At the end of 6 months, the end-points observed were lung function and the degree of reduction in the dose of oral steroids. The number of hospital admissions during the 12 months following commencement of IVIG was compared with the preceding 12 months.

RESULTS

There was a significant reduction in daily prednisolone dose from 56 +/- 31 mg to 39 +/- 35 mg (P=0.04, Wilcoxon rank sum test) and a decrease in the number of hospital admissions from 5.9 +/- 2.9 to 3.6 +/- 3.5 (P=0.04). No significant improvement occurred in lung function.

CONCLUSION

IVIG provides a potentially important adjunctive therapy in severe steroid-dependent asthma, reducing steroid requirement and decreasing hospital admissions, but not improving lung function.

Update on glucocorticoid action and resistance

Glucocorticoids (GCs) are the most common group of medications used in the treatment of allergic and autoimmune disorders. They produce potent anti-inflammatory effects by inducing or repressing the expression of target genes. Although most patients with allergic diseases and autoimmune disorders respond to GC therapy, a small subset of patients demonstrate persistent tissue inflammation despite treatment with high doses of GCs. This condition results from an interaction between susceptibility genes, the host's environment, and immunologic factors. The treatment of these patients requires a systematic approach to rule out underlying conditions that lead to steroid resistance or treatment failure, as well as the use of alternative strategies to inhibit tissue inflammation.

Anti-allergic therapies: effects on eosinophil progenitors

Marked eosinophilic infiltration is the typical inflammatory response associated with allergic inflammation. Previous research involving animal and human models has established a role for the eosinophil/basophil hematopoietic progenitor in a systemic process of allergic inflammation. In this article, we will review the evidence implicating eosinophil/basophil progenitors in this systemic response and will discuss the rationale for targeting this cell in the treatment of allergic disease. In this context, we discuss corticosteroid treatment of allergic diseases, such as asthma and its effects on hematopoietic mechanisms, the effects of therapies that inhibit the actions of cysteinyl leukotrienes, the effects of in vivo blockade of the eosinophil-active cytokine interleukin-5, and the effects of antihistamines on hematopoiesis. It is suggested that several anti-allergic therapies exert their beneficial effects on allergic inflammation by influencing eosinophil production systemically. Therefore, targeting the systemic hematopoietic response may provide additional, more beneficial, therapeutic effects.