The origin of hypersensitivity reactions and allergy Millions of Canadians suffer from allergies and asthma. When the immune system identifies a normally harmless substance as a danger, it can trigger symptoms such as sniffles, sneezing, skin rashes or respiratory problems.
Although allergies and colds have similar symptoms, there are warning signs that can help you differentiate. If you do not know if you have allergies or just a cold, ask your health professional. Your pharmacist or doctor can help you determine the cause of your symptoms and recommend appropriate treatment.
Experts believe that 1-2 per cent of Canadians have serious allergies to food, insects, medications, latex and exercise. These allergies are potentially life-threatening emergencies that require immediate medical attention.
A person experiencing a serious allergic reaction may have difficulty breathing, throat swelling of the skin redness or itching, and an irregular heartbeat or palpitations. In most cases, it is recommended that persons identified with a severe allergy to wear a MedicAlert bracelet and carry an EpiPen, which is an injection device containing epinephrine.
A recent study showed that two of three parents did not know how to use EpiPen for their child, and almost half do not even carry their EpiPen with them at all times. If you or a family member have a serious allergy, talk to your pharmacist or doctor and make sure you know how to recognize signs of a potentially fatal reaction, so you know exactly what to do if the time ever comes .
delayed hypersensitivity reactions are inflammatory reactions initiated by mononuclear leukocytes. The term delay is used to differentiate secondary cellular response, which appears 48-72 hours after exposure to the antigen, from an immediate hypersensitivity reaction, which usually appear within 12 minutes of antigen stimulation. These reactions are mediated by T cells and monocytes / macrophages rather than by antibodies. They are also called hypersensitivity reactions of type IV.
Delayed hypersensitivity is a major mechanism of defense against various intracellular pathogens, including mycobacteria, fungi and some parasites, and it occurs in graft rejection and tumor immunity. The central role of CD4 + T cells in manifests delayed hypersensitivity in patients with AIDS. Due to the loss of CD4 + cells, the host response against intracellular pathogens such as Mycobacterium tuberculosis is significantly reduced. The bacteria are ingested by macrophages, but not killed.
If T cell function is abnormal, the patient opportunistic infections, including infection by mycobacteria, fungi, parasites, and often mucocutaneous candidiasis. undesirable consequences of delayed type hypersensitivity (DTH) reactions, including diseases such as contact dermatitis and allograft rejection.
Examples DTH reactions are contact dermatitis (eg, rash and dermatitis), skin test reactions, granulomatous inflammation (eg, sarcoidosis, Crohn's disease), allograft rejection, acute graft cons the host and hypersensitivity reactions autoimmune. Interestingly, the Rhus plants, including poison ivy, poison ivy, sumac and poison, all cause rashes identical.
The cellular events that lead to delayed hypersensitivity reactions, mainly with T cells and macrophages. First, local immune responses and inflammation at the site of foreign antigen to regulate the expression of endothelial cell adhesion molecules, promoting the accumulation of leukocytes at tissue site. The antigen is engulfed by macrophages and monocytes and is presented to a T cell that has a specific receptor for that antigen. Macrophages secrete interleukin (IL) 1, IL-2, IL-6, and other lymphokines. Cytotoxic T cells can also be activated. Rookie.
Posted on March 11, 2010.
