Which is not increased in HIV infection –
**Core Concept**
HIV infection disrupts the immune system, leading to a complex interplay between various cytokines, chemokines, and other immune factors. The question is testing the student's knowledge of the immune response in HIV infection.
**Why the Correct Answer is Right**
In HIV infection, several factors are increased, including soluble CD14 (sCD14), which is a marker of monocyte activation. Additionally, the levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) are increased, indicating a chronic inflammatory response. Furthermore, the levels of neopterin, a catabolite of guanosine triphosphate (GTP), are also elevated, reflecting the activation of immune cells.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the levels of soluble CD14 (sCD14) are actually increased in HIV infection, indicating monocyte activation.
**Option B:** This option is incorrect because the levels of interleukin-6 (IL-6) are increased in HIV infection, contributing to the chronic inflammatory response.
**Option C:** This option is incorrect because the levels of tumor necrosis factor-alpha (TNF-alpha) are increased in HIV infection, indicating immune activation and inflammation.
**Option D:** This option is incorrect because the levels of neopterin are actually elevated in HIV infection, reflecting immune activation and inflammation.
**Clinical Pearl / High-Yield Fact**
In HIV infection, the increase in neopterin levels can be used as a marker of immune activation and disease progression. This is because neopterin is a catabolite of GTP, which is produced by activated immune cells.
**Correct Answer:** D.