IGHE and parasitic infectious disease: In general, these studies have revealed that parasitic infections tend to protect against allergies and autoimmunity, reducing the number of cells in bronchoalveolar lavage fluid (BALF) with particular reductions in lymphocyte and eosinophil levels together with decreases in the levels of allergen-specific IgE in the serum and BALF together with declines in airway hyperreactivity (26–28).