EFFECTS OF BCC REVACCINATION OVER THE IMMUNE RESPONSE IN ATOPIC ADULTS

The hygiene hypothesis states that some aspects related to the modern way of life contribute to the increase of allergic disease incidence in the last years. According to this hypothesis, the absence of infections that lead towards a Th1 immune response would induce the development of a Th2 immune response associated with allergic diseases. In our environment, the tuberculosis infection shows relevance and BCG (Bacille Calmette-Guerin) is a vaccine used soon after birth being efficacious against the severe forms of tuberculosis and inducing a Th1 immune response activation. Studies in animal experimental models have shown the down-modulation of Th2 immune response after BCG. Therefore, a lot of studies in different human population have been done to evaluate the possible modulation of allergic diseases induced by BCG vaccination with conflicting results. Some of these studies evaluate only the clinical aspects associated with the expression of allergic diseases whereas others compare the skin tuberculin response or the BCG scar between BCG vaccinated or non-vaccinated individuals. An important approach to solve the current controversy over BCG vaccination and allergy would be through studying the effects of BCC revaccination over the immune response in atopic adults.