AEMCA Practice Exam

Which type of white blood cell is primarily responsible for allergic reactions?

1. Neutrophils

2. Lymphocytes

3. Eosinophils

4. Monocytes

The correct answer is: Eosinophils

Eosinophils are primarily responsible for allergic reactions and play a significant role in the body's immune response to allergens. These white blood cells contain granules filled with enzymes and toxic proteins that are particularly effective against parasites and are involved in inflammatory responses. During an allergic reaction, eosinophils are recruited to the site of inflammation, where they release these granules to combat perceived threats, including allergens. In more detail, when an allergen enters the body, it can trigger the immune system to produce antibodies, particularly Immunoglobulin E (IgE). This leads to the activation of eosinophils, which then release inflammatory mediators. These mediators contribute to symptoms commonly seen in allergic reactions, such as asthma, hay fever, and hives. Therefore, the role of eosinophils is crucial in both the development and the maintenance of allergic responses. In comparison, neutrophils primarily target bacterial infections, lymphocytes are more involved in viral infections and the adaptive immune response, and monocytes can differentiate into macrophages that help clear debris and pathogens, but they are not primarily associated with allergic reactions. Understanding the specific roles of different white blood cells helps to clarify why eosinophils are the key players in allergic responses.