Which of the following in incorrect about the pathophysiology of generalized reactions?
A. Immunoglobulin E-mediated processes: because immunologic sensitization must occur, reactions do not occur with first exposures.
B. Complement system activation: reactions to blood and blood products are presumed to be associated with immune complex formation and subsequent complement activation.
C. Direct mast cell degranulation. commonly related to food and antiotics.
D. Abnormalities of arachidonic acid metabolism: systemic reactions to aspirin and nonsteroidal antiinflammatory drugs (NSAIDs).The reactions usually occur within 180 minutes of ingestion and are often associated with profuse rhinorrhea and flushing.
Answer: C
Food and antibiotics are commonly related to IgE-mediated processes.
Direct mast cell degranulation is commonly related to medications that directly induce mast cell activation and degranulation which include opiates and a variety of muscle relaxants. Systemic reactions may occur on the first exposure to such agents, because prior sensitization is not required. Tryptase is a mediator released after mast cell activation. Because the serum half-life of tryptase is 2 to 6 hours, and the concentration usually peaks 1 to 2 hours after the start of a reaction, the optimal time for sampling is within 6 hours of the onset of anaphylaxis. Sampling up to 24 hours after the start of the reaction also has clinical utility as values greater than 10 ng per mL are suggestive of mast cell activation.
Reference
Manual of Allergy and Immunology: Diagnosis and Therapy 4th edition (March 15, 2002): by Daniel C., Md. Adelman (Editor), Thomas B., Md. Casale (Editor), Jonathan, Md. Corren (Editor), Janathan Corren By Lippincott Williams & Wilkins Publishers