[Current view on the etiology of childhood bronchial asthma]

In the last decades atopic diseases and among them the incidence of atopic asthma has increased significantly worldwide, first of all in countries of higher technical civilization. In many places the incidence has doubled in 10-20 years compared to the previous period. The investigations have provided a lot of new data about genetic alterations in the background of the disease but the modifications in the genetic material cannot be responsible for the increased frequency of the disease in such a short time. It has become clear that sensibilization in connection with allergens begins in the fetus and continues in the early period after birth. Environmental allergens, especially indoor ones, the allergen burden in extrauterine life, the nutrition factors and later airway inflammations caused by virus--all contribute to the spread of atopy. The harms of civilization contribute to the dominance of T helper 2 cells and therefore to atopy in our immunosystem. It seem, that otherwise useful components like the decrease of infective diseases, vaccinations, better hygienic conditions and "western" lifestyle also manipulate our immunosystem in the direction of atopy. Our existing knowledge can provide profilactic tasks against unfavourable processes only to a very small extent.