Leukotriene Receptor Antagonists & 5-Lipoxygenase Inhibitors


Two main strategies have been developed to block the effects of cysteinyl leukotrienes in the airway. One method is to use drugs that prevent their synthesis (using a 5-lipoxygenase inhibitor) and the other involves interfering with the binding of cysteinyl leukotrienes to their cellular receptor using a leukotriene receptor antagonist (LTRA). (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…)

Systemic Allergic Reactions: Causes, Reaction, and Treatment

Systemic Allergic Reactions
Systemic allergic reactions are a relatively common clinical emergency. In their mildest form, they may just manifest as systemic cutaneous reactions with pruritis, allergy urticaria and angioedema. In more severe cases there are cardiorespiratory symptoms such as stridor, wheeze, difficulty in breathing or hypotension. Anaphylaxis has been defined as a ‘severe, life-threatening generalized or systemic hypersensitivity reaction’. The prevalence of systemic allergic reactions is unclear because of the lack of a clear, consistent definition and large prospective population studies. (more…)

Cow’s Milk Allergy: Immune Response to Protein in Milk

milk allergy

Cow’s milk is the most frequently encountered food allergen in infancy, and milk allergy is often the earliest indicator that a baby is atopic. Precise figures of the incidence of cow’s milk allergy are hard to find because of the difficulties in obtaining an accurate diagnosis, differences in the populations used for research studies, and disagreement about allergy symptoms (clinical criteria) for the condition. All studies agree, however, that cow’s milk allergy is most prevalent in early childhood with an incidence of 2 to 7.5 percent being reported. (more…)

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