Treatment to eliminate allergic reactions (see allergy) by injecting increasing strengths of purified extracts of the substance that causes the reaction. This creates special antibodies (blocking antibodies) in the patient's serum that combine with the allergen, blocking its reaction with allergic antibodies. Desensitization can also be required when a penicillin-sensitive person needs to be treated with penicillin. Seealso anaphylaxis, antigen.

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