Which statement about citrullination and inflammation is true?

Which statement about citrullination and inflammation is true?

• A. It increases during inflammation and can lead to an antigenic target
• B. It is unrelated to autoimmune responses
• C. It decreases during inflammation
• D. It is a normal housekeeping process with no immune implications

Answer: (A)

Citrullination is a post-translational modification in which arginine residues in proteins are converted to citrulline by peptidylarginine deiminases (PADs). During inflammation, Ca2+ levels rise and PAD enzymes become more active, especially in immune cells like neutrophils, leading to increased citrullination in inflamed tissues. These citrullinated proteins can reveal new epitopes—neoantigens—that the immune system may recognize as targets, particularly in individuals with a genetic predisposition. This is seen in rheumatoid arthritis, where anti-citrullinated protein antibodies are common and reflect an autoimmune response driven by inflammation-related citrullination. Thus, the statement that citrullination increases during inflammation and can lead to an antigenic target is correct. It’s not true that this process is unrelated to autoimmunity, nor that it decreases with inflammation, nor that it is simply a housekeeping function with no immune consequences.

Citrullination is a post-translational modification in which arginine residues in proteins are converted to citrulline by peptidylarginine deiminases (PADs). During inflammation, Ca2+ levels rise and PAD enzymes become more active, especially in immune cells like neutrophils, leading to increased citrullination in inflamed tissues. These citrullinated proteins can reveal new epitopes—neoantigens—that the immune system may recognize as targets, particularly in individuals with a genetic predisposition. This is seen in rheumatoid arthritis, where anti-citrullinated protein antibodies are common and reflect an autoimmune response driven by inflammation-related citrullination. Thus, the statement that citrullination increases during inflammation and can lead to an antigenic target is correct. It’s not true that this process is unrelated to autoimmunity, nor that it decreases with inflammation, nor that it is simply a housekeeping function with no immune consequences.