For a few years, the incidences of allergic diseases have been
increasing in developed countries. A disturbance in the balance of T-helper 1 (TH1)/TH2 lymphocyte responses to exogenous antigens toward a TH2 phenotype is considered a major
event in the onset of allergic diseases. Though the mechanisms
of these disturbances are still controversial, several studies
suggest a prominent role for microorganisms from the environment and the normal commensal flora of the gastrointestinal tract in these disregulations or in the prevention of allergic sensitization (15, 28). In fact, intestinal colonization