Decrease of specific and total IgE levels in allergic patients after BCG vaccination: preliminary report

BACKGROUND: A systemic reaction to mycobacteria biases the balance of T helper cell types 1 and 2 toward T helper cell type 1. BCG vaccination mimics some characteristics of mycobacterial infection. Children who have undergone tuberculin conversion after BCG vaccination seem to be more likely to lose their atopic symptoms. Inhibition of both allergic response and airway hyperreactivity after vaccination for mycobacteria has been observed in animal experiments. OBJECTIVE: To evaluate the effects that BCG vaccination has on the serological status of allergic people. PARTICIPANTS AND METHODS: This study included 20 volunteers with a history of allergic rhinitis who were required to undergo BCG vaccination by Italian law. Epicutaneous allergy testing with a panel of common seasonal and perennial inhalational allergens and 2 blood withdrawals were performed. The serum total IgE levels and the serum allergen-specific IgE levels of each individual were measured just before BCG vaccination and again 4 months later. Total IgE levels were determined using the paper radioimmunosorbent test, and allergen-specific IgE levels were determined using the radioallergosorbent test. RESULTS: Total IgE and allergen-specific IgE levels were significantly decreased after BCG vaccination (P =.004 and P<.001, respectively). CONCLUSION: BCG, an effective stimulus for cell-mediated immunity, deserves further study to evaluate its ability to modulate the immune response associated with allergic rhinitis.