A patient experiences a severe allergic reaction after receiving a second dose of penicillin. What explains why the second exposure elicits a much stronger response than the first?

💡 Explanation

Mast cell sensitization explains the enhanced response; during the initial exposure, B cells produce IgE antibodies specific to penicillin, which then bind to mast cells. Because of this sensitization, subsequent exposure triggers degranulation and histamine release, therefore causing a more intense allergic reaction, rather than a limited cytokine production.

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