Healthcare Column: Allergy

About Allergy

You may often hear the term "allergy" in daily conversation, but what does allergy mean?

The Austrian pediatrician Pirquet introduced the term “Allergy” in 1906. The word “allergy” derives from the ancient Greek words, allos (altered) and ergo (reaction).

Currently, allergy generally means the highly sensitive state against stimulations and contacts with medicines and foods in the body. Once someone has had infection such as measles, he or she can never get it again. This is caused by an immue reaction. Proteins, called antibodies, are produced against foreign substances (antigens) in the body to protect oneself, and the antibodies attack against the antigens if the antigens come into the body again.

However, aberrant reactions sometimes occur in the body, and these reactions are unfavorable for human in some cases. This is called an allergic reaction. As allergic diseases caused by allergic reactions, there are bronchial asthma, allergic rhinitis, atopic dermatitis, anaphylactic shock, autoimmune hemolytic anemia, systemic lupus erythematosus, etc.

When the antigens come into the body who has a physical constitution susceptible to allergy, antibodies against the harmless antigens are produced, which causes allergic reactions. Allergen is a general term for antigens that cause allergic reactions. There are various allergens around us, and the sensitivity to these allergens is different from each other.

There are two types of allergic rhinitis: seasonal (outdoor) one and perennial (indoor) one. Seasonal allergic disorders are caused by outdoor allergens which are Japanese cedar pollen, Japanese cypress pollen, etc. Perennial allergic disorders are caused by indoor allergens derived from house dust mites, pets' dander, etc. Since, in the case of Japanese cedar pollen, pollen forecast (see figure below) is updated annually by the Ministry of the Environment and private organizations, the early treatment of hay fever based on the forecast is thought to be effective. It is said that starting the preparation a few weeks before pollen scattering is the effective countermeasure against hay fever.

Threat of Allergy

Based on the basic survey of health and welfare in 2003 issued by the Ministry of Health, Labor and Welfare, about one-third of the population in Japan have any allergic symptoms. A majority of the population in Japan is thought to be susceptible to allergens today if people with allergic predisposition are included. Actually, the number of patients suffering hay fever is increasing steadily.

Atopic dermatitis, also called eczema, is a pruritic skin disorder that usually appears in babies or very young children. This disease is chronic with repeated exacerbations and remissions, and is easily complicated by other allergic disorders such as bronchial asthma, allergic rhinitis, allergic conjunctivitis, etc. A majority of patients with atopic dermatitis have spontaneous resolution by the puberty (between the ages of 12 and 15 years).

However, the number of adult patients with atopic dermatitis is increasing recently. Adult atopic dermatitis is caused due to many reasons that are different from infants' and children's one. Adult atopic dermatitis can be triggered not only by allergens from house dust mites, house dust, molds and foods but also by psychological stress. In the case of adult atopic dermatitis, the condition of 20-40% of the patients is deteriorated by psychological stress.

Allergy and Lactic acid bacteria

Recent research in allergy has cleared the relationship between intestinal bacteria and immunity. Beneficial and harmful bacteria reside in intestinal tract in which they are continually disputing over territory.

The higher intake of animal fats and proteins helps the proliferation of harmful bacteria in intestinal tract. The increase of the number of harmful bacteria in intestinal tract results in the overflow of detrimental components in intestinal tract, the intestinal decomposition, and the immune depression. These accelerate allergic disorders, various diseases and senescence.

It has been cleared that allergic disorders in children is correlated with the decrease of lactic acid bacteria in their intestinal tracts. This means that the increase of lactic acid bacteria is expected to balance the immune reaction and prevent the onset of allergic disorders.

There are various types of lactic acid bacteria. The specified bacteria among them have strong effect on allergic disorders. These types of lactic acid bacteria balance the immune systems inside the body and fundamentally improve the allergic disposition. This effect of lactic acid bacteria has been in the spotlight, since, unlike symptomatic treatment, these bacteria have ability to improve the physical constitutions against allergic disorders from the inside the body. We have reported in academic journals that the extracts of lactic acid bacteria Enterococcus faecalis FK-23 have anti-allergic effect.

In a clinical test, the leukocyte population in blood before and after the intake of extracts of Enterococcus faecalis FK-23 was investigated. A figure below shows that the number of allergen-induced eosinophils is suppressed in the FK-23 extracts-administered group.

The red and blue bars indicate the number of each cell in the blood before and after the intake of FK-23 extracts, respectively. The vertical axis represents the number of cells in the blood. The following types of cells are listed on the horizontal axis from left to right, whole white blood cell, neutrophil, lymphocyte, eosinophil, basophil, and monocyte.