Mast cells vs Basophils and eosinophils
How to tell Mast cells and Basophils and eosinophils apart when a board question makes them look alike.
Mast cells are tissue IgE degranulators; basophils are circulating granulocytes; eosinophils are helminth/allergy effector cells.
Side by side
Mast cells are tissue-resident IgE-bearing cells that degranulate histamine and mediate allergy, anaphylaxis, and parasite responses.
Basophils circulate in blood and resemble mast cells; eosinophils kill helminths and participate in allergy using major basic protein.
Mast cells are tissue-resident IgE-bearing cells that degranulate histamine and mediate allergy, anaphylaxis, and parasite responses.
Basophils circulate in blood and resemble mast cells; eosinophils kill helminths and participate in allergy using major basic protein.
The repair move
Before naming the answer, force the stem through the separator: Mast cells are tissue IgE degranulators; basophils are circulating granulocytes; eosinophils are helminth/allergy effector cells.
Try a free question
CoreA skin biopsy from a patient with urticaria pigmentosa shows tissue-resident granulocytes in the dermis with metachromatic granules containing histamine, heparin, and tryptase. These cells have high-affinity IgE receptors (Fc-epsilon-RI) and degranulate in response to allergen cross-linking of bound IgE. Which cell type is this?
Show answer and explanation
Answer: A. Mast cells. Mast cells are TISSUE-RESIDENT granulocytes (skin, mucosa, lung, GI tract, near blood vessels) with high-affinity IgE Fc-epsilon-RI receptors. Degranulate in response to allergen cross-linking of bound IgE, releasing histamine, heparin, tryptase, leukotrienes, prostaglandins, and cytokines. Mediate type I hypersensitivity, allergy, anaphylaxis, and helminth defense. Mastocytosis (urticaria pigmentosa, systemic mastocytosis) has elevated serum tryptase.
Why the other choices are tempting
- B. Basophils are CIRCULATING granulocytes similar to mast cells in function; bound IgE and granules but in blood, not tissue.
- C. Eosinophils kill helminths via major basic protein (MBP), eosinophil cationic protein, and reactive oxygen species; involved in allergy.
- D. Neutrophils are phagocytes for bacterial infection.
- E. Macrophages are tissue phagocytes derived from monocytes.
Flashcards
Tap a card to flip it.
What clue supports Mast cells?
Choose Mast cells when the stem gives this pattern: Mast cells are tissue-resident IgE-bearing cells that degranulate histamine and mediate allergy, anaphylaxis, and parasite responses.
What clue supports Basophils and eosinophils?
Choose Basophils and eosinophils when the stem gives this contrasting pattern: Basophils circulate in blood and resemble mast cells; eosinophils kill helminths and participate in allergy using major basic protein.
Quick answers
What is the fastest way to tell Mast cells from Basophils and eosinophils?
Mast cells are tissue IgE degranulators; basophils are circulating granulocytes; eosinophils are helminth/allergy effector cells.
What is the key clue for Mast cells?
Mast cells are tissue-resident IgE-bearing cells that degranulate histamine and mediate allergy, anaphylaxis, and parasite responses.
What is the key clue for Basophils and eosinophils?
Basophils circulate in blood and resemble mast cells; eosinophils kill helminths and participate in allergy using major basic protein.