The effect of IL-4 on human nasal mucosal responses

Rapid and sustained effect of dupilumab on clinical and mechanistic outcomes in aspirin-exacerbated respiratory disease

BACKGROUND

Dupilumab, a mAb targeting IL-4Rα, improves upper and lower airway symptoms in patients with aspirin-exacerbated respiratory disease (AERD), but the mechanisms leading to clinical improvement are not fully elucidated.

OBJECTIVE

Our aim was to identify the mechanistic basis of clinical improvement in patients with AERD treated with dupilumab.

METHODS

A total of 22 patients with AERD were treated with dupilumab for 3 months for severe asthma and/or chronic rhinosinusitis with nasal polyps. Clinical outcomes were assessed at baseline and at 1 and 3 months after initiation of dupilumab. Nasal fluid, urine, blood, and inferior turbinate scrapings were collected at the 3 time points for determination of mediator levels, cellular assays, and RNA sequencing.

RESULTS

Participants had rapid improvement in clinical measures, including sense of smell, sinonasal symptoms, and lung function after 1 month of treatment with dupilumab; the improvements were sustained after 3 months of dupilumab. Baseline severity of smell loss was correlated with lower nasal prostaglandin E₂ levels. Dupilumab increased nasal prostaglandin E₂ level and decreased levels of nasal albumin, nasal and urinary leukotriene E₄, and serum and nasal IgE. Transcripts related to epithelial dysfunction and leukocyte activation and migration were downregulated in inferior turbinate tissue after treatment with dupilumab. There were no dupilumab-induced changes in nasal eosinophilia.

CONCLUSION

Inhibition of IL-4Rα in AERD led to rapid improvement in respiratory symptoms and smell, with a concomitant improvement in epithelial barrier function, a decrease in inflammatory eicosanoid levels, and an increase in the anti-inflammatory eicosanoid prostaglandin E₂ level. The therapeutic effects of dupilumab are likely due to decreased IL-4Rα signaling on respiratory tissue granulocytes, epithelial cells, and B cells.

Immune-related gene expression in response to H5N1 avian influenza virus infection in chicken and duck embryonic fibroblasts

Chicken and ducks are important hosts in responses to highly pathogenic avian influenza virus (HPAIV) H5N1 infection. In ducks, avian influenza (AI) generally causes an asymptomatic and long-lasting infection, whereas clinical apparent and transient disease is often observed in chickens. Using real-time quantitative PCR, we examined the expression of immune-related genes in response to H5N1 infection in chicken embryo fibroblasts (CEF) and duck embryo fibroblasts (DEF). While in CEF IL-6 expressed at high levels similar to mammalian species, in DEF expression levels were minimal. Similarly, duck IFN-β expression were slightly upregulated, whereas chicken expressions were highly upregulated. Chronologically, the mRNA levels of both IFN-alpha and IFN-gamma, which belong to type I and type II interferon, respectively, were unregulated in a similar fashion in chickens than in ducks. IL-2 and TLR-7 were elevated from the beginning of the infection in both CEF and DEF to the end of the experiment. Chicken MHC class I expression was almost unaffected while duck expression were downregulated. DEF and CEF MHC class II expression were downregulated. Chemokine IL-8 expression was upregulated in both species. The IL-8 levels closely parallel the IL-1β induced IL-6 levels in the same samples. These results show distinct embryo fibroblasts expression patterns of pro-inflammatory cytokines and IFNs between species.

The pathophysiology, clinical impact, and management of nasal congestion in allergic rhinitis

BACKGROUND

Nasal congestion is a cardinal symptom of allergic rhinitis (AR). It is difficult to treat and is associated with decreased quality of life.

OBJECTIVE

This article reviews the clinical features of nasal congestion, its complex pathophysiology in the context of AR, its clinical impact, and the strengths and weaknesses of available treatments.

METHODS

Primary studies and reviews in the peer-reviewed, English-language literature were identified through searches of MEDLINE (1966-2008) and the Cochrane Library (1996-2008) using the terms nasal congestion, allergic rhinitis, pathophysiology, quality of life, and burden. Additional references were obtained by searching the reference lists of the identified articles. Abstracts from the 2006 and 2007 meetings of the American Academy of Allergy, Asthma, and Immunology were also searched. Pertinent articles were included in the review if they were recently published and patient-focused, and if their authors were recognized leaders in the field.

RESULTS

A survey of 2355 patients with AR or their guardians found that almost half of respondents rated nasal congestion the most bothersome symptom; in a survey of 2500 adults with AR, 78% rated nasal congestion either extremely or moderately bothersome. Histamine and leukotrienes are major mediators of the allergic inflammation associated with nasal congestion, as indicated by reductions in nasal cross-sectional area in response to histamine challenge (P<0.001) and increases in nasal airway resistance in response to leukotriene challenge (P<0.05).Therapy for nasal congestion in AR is often hampered by limitations associated with the individual agents; for example, decongestants are effective in the control of nasal congestion, but their use is restricted by their adverse-event profiles. A meta-analysis of 16 controlled studies involving 2267 patients with AR found that intranasal corticosteroids provided significantly greater relief of nasal congestion than oral antihistamines (95% CI for combined standardized mean difference, -0.73 to -0.53). The results of several clinical trials have suggested that leukotriene-receptor antagonists may be associated with reduced nasal congestion; however, no agents in this class are currently approved for the treatment of nasal congestion in AR.

CONCLUSION

There is a need for therapies that are well tolerated and effective in relieving nasal congestion in AR.

Comparison of the effects of desloratadine 5-mg daily and placebo on nasal airflow and seasonal allergic rhinitis symptoms induced by grass pollen exposure

BACKGROUND

Nasal congestion is a chronic symptom of seasonal allergic rhinitis (SAR) that is often difficult to treat with antihistamines. Desloratadine, a new, potent, H1-receptor antagonist has been shown to decrease nasal congestion in clinical trials and to maintain nasal airflow in response to grass pollen exposure. We compared the effects of desloratadine 5 mg and placebo on nasal airflow, nasal secretion weights and SAR symptoms, including nasal congestion, in patients exposed to grass pollen in an environmental exposure unit.

METHODS

Forty-six grass pollen allergic SAR patients received desloratadine or placebo for 7 days, followed by a 10-day washout, and then crossed over to the other treatment for 7 days. A 6-h allergen exposure was performed at the end of each treatment period.

RESULTS

Desloratadine was significantly superior to placebo in maintaining nasal airflow (P <or= 0.014) and lessening the increase in nasal secretion weights (P < 0.001) throughout allergen exposure. SAR symptom scores, including nasal congestion, were significantly less with desloratadine than placebo (P <or= 0.001). Desloratadine was well tolerated.

CONCLUSIONS

This study confirms that, compared with placebo, desloratadine can maintain nasal airflow and reduce nasal secretion weights and the severity of SAR symptoms, including nasal congestion, in SAR patients exposed to grass pollen allergen.

Decongestant efficacy of desloratadine in patients with seasonal allergic rhinitis

Recent advances in experimental immunologic approaches to seasonal allergic rhinitis (SAR) have led to a shift in the concepts of its pathogenesis. The conventional view of SAR as a local response to inhaled allergens has largely given way to a new view of this disorder as a systemic condition with local tissue manifestations. This concept, together with an increasing recognition of specific mediators' distinct roles in driving the early- and late-phase allergic responses, has opened multiple lines of therapeutic attack within the allergic cascade. Potent inhibition of inflammatory mediator release at distinct points in this cascade is conferred by desloratadine. In addition to the familiar range of SAR symptoms amenable to antihistamine therapy, desloratadine uniquely attenuates patient ratings of nasal congestion. This novel, nonsedating histamine H1-receptor antagonist is the only once-daily antiallergic product with a consistent decongestant effect that begins within hours of the first morning dose and is sustained for the entire treatment period.

New insights into the pathogenesis and treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic multisystemic inflammatory disease with autoimmune features, and of unknown cause, associated with characteristic joint deformities and increased mortality rate. The pathogenesis of this serious disease seems to be multifactorial, where several cytokines, particularly interleukin-1 and tumor necrosis factor-alpha, are strongly involved in the induction and perpetuation of the chronic inflammatory process of the joints in RA and in the systemic manifestations of the disease. Other factors, such as reactive oxygen species and metalloproteinases, may also participate in the destruction of the rheumatoid joint. Current treatments of RA are inadequate in that they only partially control established RA, and despite optimal use of current antirheumatic agents, the outcome of many patients with RA consists of pain, severe functional decline, and premature death. The gloomy recent data regarding the prognosis of RA with the use of the current treatments stress the need for new therapeutic regimens with the ability to effectively control the inflammatory process in the rheumatoid joint and to induce long-term remission or even cure. Controlling the production and the activity of the factors involved in the pathogenesis of the disease represents the major therapeutic goal. Since several factors are involved in the pathogenesis of RA, neutralizing one or some of these factors may be of only limited benefit. In this regard, interleukin-4 may be a very promising agent for an effective treatment of RA, because this cytokine is not limited by its inhibitory effects to a single factor, but rather it inhibits most of the main factors involved in the pathogenesis of the disease. Although recent data strongly support this approach with interleukin-4, controlled long-term clinical trails should be undertaken in order to prove the validity and the effectiveness of this promising approach.