IGHE and infection: Evidence shows that infection with M. bovis- Bacillus Calmette–Guérin (BCG) prevents airway eosinophilia, develops airway hyper responsiveness (AHR), and partially reduces the levels of allergen-specific IgE/IgG1 serum antibodies in the model of ovalbumin (OA)-induced allergic disease in mice, rats or guinea pigs (32, 35); which support the results of the present study.