A 26-year-old man has had myalgias and a fever for the past week. On physical examination, his temperature is 38.6deg C. He has diffuse muscle tenderness, but no rashes or joint pain on movement. Laboratory studies show elevated serum creatine kinase and peripheral blood eosinophilia. Larvae of Trichinella spiralis are present within the skeletal muscle fibers of a gastrocnemius biopsy specimen. Two years later, a chest radiograph shows only a few small calcifications in the diaphragm. Which of the following immunologic mechanisms most likely contributed to the destruction of the larvae?
Correct Answer: Antibody-mediated cellular cytotoxicity (ADCC)
Description: When antibody is directed at a parasitic infection, there is Fc receptor-mediated inflammation and phagocytosis, characteristic for ADCC. IgG and IgE antibodies bearing Fc receptors coat the parasite. Macrophages, natural killer cells, and neutrophils can then recognize the Fc receptor and destroy the antibody-coated target cells. Acute inflammatory reactions with abscess formation have little effect against tissue parasites. Complement-mediated lysis is most typical of immune destruction of RBCs with hemolysis. Langhans giant cells are seen in granulomatous inflammation, a form of type IV hypersensitivity. Leukotriene C4 is a potent agent that promotes vascular permeability and bronchial smooth muscle contraction in type I hypersensitivity reactions.
Category:
Pathology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now