American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What is the role of IL-6 in the inflammatory response?

1. Inhibits viral replication

2. Increases acute phase proteins such as CRP and amyloid A

3. Promotes PMN chemotaxis

4. Decreases inflammatory response

The correct answer is: Increases acute phase proteins such as CRP and amyloid A

Interleukin-6 (IL-6) is a crucial cytokine in the inflammatory response. Its primary role is to stimulate the production of acute phase proteins by the liver, which include C-reactive protein (CRP) and serum amyloid A. These acute phase proteins play a significant role in the body's defense mechanisms during inflammation by enhancing opsonization, promoting phagocytosis, and modulating the immune response. When inflammation occurs, IL-6 levels rise significantly, leading to the synthesis of these proteins. CRP, in particular, is a well-known marker for inflammation and serves as an indicator in clinical settings for the presence and intensity of inflammatory processes. The production of these acute phase proteins is a critical part of the body's response to tissue injury, infection, and other inflammatory stimuli. Understanding the role of IL-6 in this context is vital for recognizing its importance in various disease processes, including autoimmune diseases, infections, and even cancer, where a persistent increase in IL-6 may contribute to ongoing inflammation and tissue damage.