Immunology

How to prevent and treat eye allergies

(HealthDay)—When it comes to allergies, allergic rhinitis with its congested, itchy nose gets a lot of attention. But for some, allergic conjunctivitis with itchy, watery eyes is the greater nuisance. You might even have ...

Medical research

Researchers breathe new life into COPD research using mouse models

The airways and lungs are affected by a range of diseases, but while some have been well characterized and treated, others, such as chronic obstructive pulmonary disorder (COPD), are still somewhat of an enigma. This condition ...

Immunology

Scientists find molecular 'switch' for allergic asthma treatment

A team of Russian scientists has identified the role of the interleukin-6 molecule in the development of allergic asthma. It may comprise a new target for the treatment of this disease. The results are published in Frontiers ...

Immunology

Asthma medications: Know your options

Confused about your asthma medications? Here's what you need to know to sort out the main classes and numerous subtypes of asthma drugs.

Inflammatory disorders

Cellular changes lead to chronic allergic inflammation in the sinus

Chronic rhinosinusitis is distinct from your average case of seasonal allergies. It causes the sinuses to become inflamed and swollen for months to years at a time, leading to difficulty breathing and other symptoms that ...

Immunology

Scientists unearth cell 'checkpoint' that stops allergic diseases

Scientists from Trinity College Dublin have made a significant breakthrough in understanding the regulation of immune cells that play a pivotal role in allergic diseases such as asthma and eczema. They have identified a 'checkpoint' ...

Neuroscience

Targeting nerve endings to curb allergic asthma

Current asthma medications, which work by suppressing inflammatory signaling by immune cells or by dilating the airways, can stop working over time. A study from Boston Children's Hospital, Brigham and Women's Hospital, and ...

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Allergic inflammation is an important pathophysiological feature of several disabilities or medical conditions including allergic asthma, atopic dermatitis, allergic rhinitis and several ocular allergic diseases. Allergic reactions may generally be divided into two components; the early phase reaction, and the late phase reaction. While the contribution to the development of symptoms from each of the phases varies greatly between diseases, both are usually present and provide us a framework for understanding allergic disease .

The early phase of the allergic reaction typically occurs within minutes, or even seconds, following allergen exposure and is also commonly referred to as the immediate allergic reaction or as a Type I allergic reaction . The reaction is caused by the release of histamine and mast cell granule proteins by a process called degranulation, as well as the production of leukotrienes, prostaglandins and cytokines, by mast cells following the cross-linking of allergen specific IgE molecules bound to mast cell FcεRI receptors . These mediators affect nerve cells causing itching , smooth muscle cells causing contraction (leading to the airway narrowing seen in allergic asthma) , goblet cells causing mucus production , and endothelial cells causing vasodilatation and edema .

The late phase of a Type 1 reaction (which develops 8-12 hours and is mediated by mast cells) should not be confused with delayed hypersensitivity Type IV allergic reaction (which takes 48-72 hours to develop and is mediated by T cells). The products of the early phase reaction include chemokines and molecules that act on endothelial cells and cause them to express Intercellular adhesion molecule (such as vascular cell adhesion molecule and selectins), which together result in the recruitment and activation of leukocytes from the blood into the site of the allergic reaction . Typically, the infiltrating cells observed in allergic reactions contain a high proportion of lymphocytes, and especially, of eosinophils. The recruited eosinophils will degranulate releasing a number of cytotoxic molecules (including Major Basic Protein and eosinophil peroxidase) as well as produce a number of cytokines such as IL-5 . The recruited T-cells are typically of the Th2 variety and the cytokines they produce lead to further recruitment of mast cells and eosinophils, and in plasma cell isotype switching to IgE which will bind to the mast cell FcεRI receptors and prime the individual for further allergic responses.

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