Medical Laboratory Scientist ASCP Practice Exam 2025 – Complete Study Guide

In cases of mild allergic reactions, mast cells play a crucial role in mediating the allergic response. These cells are a type of white blood cell that contains granules filled with histamine and other mediators. When an allergen is encountered, mast cells become activated and degranulate, releasing these substances into the surrounding tissues. The released histamine leads to symptoms such as itching, vasodilation, and increased vascular permeability, which are characteristic of mild allergies.

While other cell types, such as eosinophils, macrophages, and lymphocytes, are indeed involved in immune responses, they are more commonly associated with different aspects or phases of allergic reactions and immune responses. Eosinophils are particularly involved in more severe allergic responses and asthma, macrophages play a role in phagocytosis and immune regulation rather than in direct allergic reactions, and lymphocytes are integral to the adaptive immune response but are not the primary cells activated during a mild allergic response. Thus, the predominant activation of mast cells in mild allergic reactions explains their central role in initiating and promoting such responses.