Unfortunately, allergy season never ends. It can be a different time of year, depending on a person’s particular allergy. Because the changing seasons occur differently in different temperate zones, the allergy seasons can be different depending on where you live.
Allergens that are most bothersome in spring include tree pollens, released as part of the natural reproduction process of these plants. Some of the most common tree allergens are Ash, Birch, Cypress and Elm. Some people are affected by Hickory, Maple, Oak or Poplar. Many other trees cause allergens, but these are the most common. Grasses can also trigger allergies in the spring. Bermuda grass, Bluegrass, and Timothy grass are among the worst of them.
Weed allergens are still present in the early autumn. Mold spores are also very active at this time. The wet leaves decaying on the ground create a fertile breeding ground for mold. Allergies can be triggered by molds like alternaria, cladosporium and aspergillus.
Winter is the time for indoor allergies. These are commonly caused by dust mites, animal dander, indoor mold, insects or mice.
Some poor souls suffer from allergies all year. Allergies happen when the body reacts to airborne pollen or mold spores. It is the result of an overzealous immune system attacking perceived threats. It is often an inherited condition involving a complex series of immune reactions.
Histamine can cause many symptoms depending on the part of the body affected. You may experience itchy eyes and nose, watering eyes, sneezing, wheezing, hives, nausea, vomiting or diarrhea. Allergens that affect the sinuses are often called hay fever. Allergic reactions in the lungs are called asthma. When the skin is affected, we call in hives. Intestinal upset from allergens is usually called a food allergy. If the reaction is system-wide and severe, it is called anaphylaxis. This is the most dangerous form of allergy, sometimes leading to death.
These irritating and sometimes harmful symptoms are caused by an immune reaction. The immune system works like a police squadron, responding to criminal invaders. Lymphocytes, a type of white blood cell, cruise through all parts of the body. When they encounter particles they cannot identify or diseased cells, they take a snap shot or fingerprint of the invader by taking note of its surface protein markers.
This fingerprint is used to identify the invader more quickly the next time it is encountered. After an encounter, some lymphocytes become memory cells, living for years and sometimes decades, ready to identify the invader again to tailor its attack. Other lymphocytes turn into plasma, releasing antibodies to attack the diseased cell.
The Role of Lymphocytes
Lymphocytes come in two classes, designed for different jobs. In some cases, these two types of lymphocytes work together in the immune response. T-Lymphocytes, commonly called T cells, are made in the thymus and are only allowed to enter the rest of the body when they can identify native cells from foreign ones. Without this safeguard, these cells could attack healthy tissues and create havoc in the body. This sometimes happens, resulting in autoimmune disorders like rheumatoid arthritis.
T cells are like the SWAT team, deployed in serious situations. Some T cells, called Killer T cells actually puncture diseased cells and inject enzymes that kill the cells. Suppressor T cells help prevent these Killer T cells from going overboard. Finally, there are Helper T cells that work to assist the other type of lymphocyte, B cells, in their immune response.
B cells are made in the bone marrow. They have receptors on the surface that allow them to attach to foreign substances. They do not directly attack cells, but instead call other proteins in the blood to help destroy histamine-containing cells and release this hormone, needed to fight off invaders. These same lymphocytes cause the body to reject transplants. The main job of B cells is to identify and destroy parasitic infections, but they are also responsible for allergies.
The genetic information stored in a lymphocyte is supposed to distinguish non-harmful proteins from the proteins of foreign cells. However, those who suffer from allergies are missing some of the genetic code and therefore cannot tell the difference. To be on the safe side, they react to anything that looks like it could possibly be an invader.
When a Foreign Particle is Found
The B cell that encounters a foreign particle, or antigen, reacts as described before. After fingerprinting the antigen, the B cells travel to the lymph node. Here, some change into plasma, producing antibodies custom designed to deal with the foreign particle and others become memory cells.
The antibodies produced in an allergic reaction are called IgE. This is one of five types of antibodies produced in the body. While everyone makes IgE antibodies, those prone to allergies have larger amounts of IgE in the bloodstream and digestive mucus. The lgE antibodies attach to histamine-containing cells called mast cells and basophils, ready to attack if histamine is needed. Mast cells are found in tissue and basophils are in the bloodstream.
The first exposure to an allergen is called a sensitizing exposure. Initially, there is no allergic reaction but the next time the body encounters the allergen, the IgE antibodies respond. They recognize the protein surface markers, or fingerprint, of the allergen. These antibodies are already attached to mast cells, but they bind to the protein surface markers of the invader as well. The binding alerts proteins in the blood, called the complement complex to attach.
One by one, each protein attaches to the cell and alerts the next protein. Finally, the chain of proteins destroys the cell, releasing its cache of histamine. This system is very effective for killing unwanted invaders. In a healthy immune system, the antibodies would have been attached to parasitic cells, but the process is the same. The body uses histamine as a way to stimulate blood flow to the site so the body can more effectively fight off the invader.