A sample of John's blood shows a high level of pyrogens. This would indicate that John:

• A. has a deficiency in phagocytic cells
• B. is undergoing an allergic reaction
• C. has an increased production of antibodies
• D. is experiencing a fever as part of his innate immune response

Answer: (D)

Verified step by step guidance

1. Understand what pyrogens are: Pyrogens are substances, often produced by bacteria or immune cells, that can induce fever by acting on the hypothalamus in the brain.
2. Recognize the role of pyrogens in the immune response: When pyrogens are present in the blood, they trigger the body's innate immune system to raise the body temperature, resulting in fever.
3. Analyze the options given: A deficiency in phagocytic cells, an allergic reaction, or increased antibody production do not directly explain the presence of pyrogens in the blood.
4. Connect the presence of pyrogens to fever: Since pyrogens cause fever as part of the innate immune response, a high level of pyrogens indicates that John is experiencing a fever.
5. Conclude that the correct interpretation of high pyrogen levels is that John is undergoing a fever, which is a natural defense mechanism to help fight infection.