Early life events in allergic sensitisation.

The timing of events leading to allergic sensitisation has become a very important area in the attempt to halt the dramatic increase in the prevalence of diseases such as asthma, eczema and hay fever. Recent research has demonstrated that events taking place during the gestational period may well play a role in determining whether or not a genetic susceptibility becomes translated into disease processes. Maternal atopy seems to have an important effect on the developing immune response of the infant and increases the chances of the child developing allergy in later life. Maternal IgE, IgG and amniotic fluid cytokines, combined with the presence of allergen in the feto-maternal environment are all possible factors involved in the ultimate outcome in terms of infant Th-1/Th-2 responses to common environmental antigens. Immune modulation at this stage of development may, in the future, be a way forward in the prevention of allergy.