The appearance of red, swollen, nasal mucosa from allergy to ragweed pollen has been mediated by:

Histamine

Abacavir

Nevirapine

Stavudine

The appearance of red, swollen, nasal mucosa from allergy to ragweed pollen has been mediated by: Histamine
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During allergic reactions, basophils release two enzymes, histamine, and heparin.
Mast cells are multifunctional bone marrow-derived tissue-dwelling cells that are the major producer of histamine in the body During allergic reactions.