Long Acting Agonist (ß2) Therapy to Inhaled Corticosteroids in Persistent Asthma?

long acting agonist
Current internationally recognized guidelines indicate that symptomatic asthmatics using a low to medium inhaled corticosteroid dose (400–800 µg/day of beclomethasone or equivalent) alone should preferentially be commenced on a long-acting agonist ß2 prior to an leukotriene receptor antagonists LTRA (British guideline on the management of asthma 2003; GINA Workshop Report 2004). However, two recent large trials have performed head to-head comparisons of add-on long-acting ß2 agonist versus LTRA as therapeutic adjuncts to inhaled corticosteroids, using exacerbation frequency (rather than lung function and symptoms) as the primary end point. (more…)

Histamine Type-2 Receptor as Major Player in Peripheral Tolerance

histamine receptor
Histamine is a low-molecular-weight monoamine that binds to four different G-protein-coupled receptors, and has recently been demonstrated to regulate several essential events in the immune response. The histamine receptor type 2 (HR2) is coupled to adenylate cyclase and studies in different species and several human cells have demonstrated that inhibition of characteristic features of the cells by primarily cAMP formation dominates in HR2-dependent effects of histamine. (more…)

Sublingual Immunotherapy Mechanisms

sublingual immunotherapy
The immunologic mechanisms of sublingual immunotherapy are less established. In Cochrane analysis, the authors concluded that there was an increase in IgG4 but no stable effect on IgE levels in adults. In addition, the induction of allergen-specific IgA has been reported. There are conflicting data concerning lympho-proliferative responses. So far the evidence on changes in Th1/Th2/Treg activity induced by sublingual immunotherapy need to be confirmed. The effects on T-cell reactivity and cytokine secretion show strong variation in a number of studies. (more…)

Treg Cells In Allergen-Specific Immunotherapy

treg cells
Treg cells or regulatory T cells constitute a large population of cellular infiltrate in atopic/allergic inflammation and a dysregulated immune response appears to be an important pathogenetic factor. Cardinal events during allergic inflammation can be classified as activation, organ-selective homing, survival and reactivation, and effector functions of immune system cells. T cells are activated by aeroallergens, food antigens, autoantigens, and bacterial exotoxins superantigens in allergic inflammation. They are under the influence of the skin, lung, or nose-related chemokine network and show organ-selective homing. (more…)

Allergen-Specific Immunotherapy Mechanisms & The Involvement Of Treg Cells

allergen specific immunotherapy
Allergen-specific immunotherapy is highly effective in the treatment of IgE-mediated allergy diseases such as rhinitis, conjunctivitis, asthma, and venom allergy hypersensitivity. It is the only treatment that leads to lifelong tolerance against previously disease-causing allergens due to restoration of the normal immunity. (more…)

Regulatory T Cells (Treg) Therapeutic Application

treg
An emerging concept is that pro-inflammatory signals lead to loss of Regulatory T Cells (Treg) function. Pasare and Medzhitov (2003) demonstrated that activation of DCs through TLRs led to the production of signals, including IL-6, which blocked the suppressive effect of CD4+CD25+ Treg. Subsequent studies support these observations. For example in a mouse model of allergic airway disease, IL-6 is proposed to act via two mechanisms to promote disease: direct enhancement of Th2 responses and by overcoming the suppressive function of CD4+CD25+ Treg. Tumor necrosis factor (TNF) as well as IL-7 and IL-15 have also been proposed to overcome regulatory activity in other human immunologic diseases. (more…)

Foxp3 Forkhead Winged Transcription Factor & Mechanisms Of Suppression

foxp3
The intracellular forkhead winged transcription factor Foxp3 (forkhead box P3) appears to be specifically expressed by naturally occurring Treg cells, particularly in mice, although in humans there is evidence of upregulation of Foxp3 in all T cells on activation. Foxp3 is required for the development and function of naturally occurring regulatory t cells (treg) and expression is sufficient to convert non-regulatory CD4+CD25T cells into cells with regulatory activity. Conversion of peripheral CD4+CD25 naive T cells to Foxp3+CD4+CD25 foxp3+ Treg cells can be induced by TGF-ß. In a murine asthma model, these TGF-ß-induced Treg prevented house-dust mite-induced allergic pathogenesis or infection pathogenesis in lungs. A single independent report has suggested that IL-4 and IL-13 also induce Foxp3+CD25+ Treg from CD4+CD25precursors. (more…)

Allergic Responses Prevention: Regulatory T Cells (Treg)

Regulatory T Cells
The induction of immune tolerance and specific immune suppression are essential processes in the control of immune responses. Regulatory T cells (Treg) play a central role in immune control in the periphery. Two broad categories of Treg have been described: naturally occurring Treg that are present in all individuals and antigen-induced Treg that secrete inhibitory cytokines such as interleukin (IL)-10 and/or transforming growth factor (TGF)-ß. (more…)

Antileukotriene Drugs for Airway Hyperresponsiveness & Asthma Treatment

antileukotriene
A variety of proinflammatory cells, mediators, and cytokines orchestrate the development of airway hyperresponsiveness, which results in the episodic airflow obstruction characteristic of asthma. As a consequence, modulation of the underlying disease process with antii-nflammatory agents is firmly established as being the cornerstone of successful management. Inhaled corticosteroids are the most potent antiinflammatory agents available and satisfactorily suppress underlying airway inflammation in most individuals. (more…)

Immunoglobulin E (IgE) Regulation and Biology

immunoglobulin e
Normally present at very low levels in plasma, antibodies of the immunoglobulin E (IgE) isotype were first discovered in 1967, decades after the description of IgA, IgG, and IM. IgE antibodies are produced primarily by plasma cells in mucosal-associated lymphoid tissue and their levels are uniformly elevated in patients suffering from atopic conditions like allergic rhinitis, asthma and atopic dermatitis. Production of allergen-specific IgE in atopic individuals is driven both by a genetic predisposition to the synthesis of this isotype as well as by environmental factors, including chronic allergen exposure. (more…)

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