Which of the following describes a qualitative defect in phagocytes?

• A. Overreaction to pathogens
• B. Chemotactic defects
• C. Excessive phagocyte activity
• D. An inability to form pus

Answer: (B)

The choice that describes a qualitative defect in phagocytes is related to chemotactic defects. Chemotaxis is the process by which phagocytes are directed to the site of infection or inflammation. A qualitative defect in phagocytes indicates an issue with the functional performance of these immune cells, not merely with their numbers.

Chemotactic defects specifically refer to the inability of phagocytes to properly respond to chemical signals that guide them to areas where immune response is needed. This impairment can lead to poor recruitment of phagocytes to sites of infection, diminishing the body’s ability to combat pathogens effectively.

In contrast, overreaction to pathogens would suggest an exaggerated response, which is more aligned with an inappropriate immune response rather than a defect. Excessive phagocyte activity is indicative of a hyperactive immune system, also not a defect. An inability to form pus can be associated with a quantitative issue and does not specifically illustrate the functional capabilities of phagocytes in the context of their chemotactic response.