pharmacology - How does paracetamol interfere with immune system?

Paracetamol is used to reduce body temperature when it is to high. The high body temperature (fever) is known to be an indication that immune system fights against an infection.

In this context I have two related questions:

1. Is high body temperature one of the mechanisms of immune system to suppress an infection or it is just a side effect?



2. If it is just a side effect, does paracetamol remove it by decreasing the intensity with which immune system fights with an infection or not?

Answer

First question: Yes. The immune system releases pyrogenic cytokines such as IL-1. Bacteria aren't typically used to 37C, they prefer working at under that temperature to function in the environment. Our body however can take a few degrees here or there however this severely compromises the bacterial enzyme activity. The same is true for other pathogen enzymes. The body also increases copper concentrations in the blood for similar reasons. Problem is of course if the body goes into overdrive and raises our temperature too much, this compromises our own ability to fight the infection so in that case antipyretics like paracetamol can reduce fever.

Second question. It isn't a side effect, however paracetamol works by blocking things like IL-1 that raise temperature. How IL-1 raises your temperature is quite interesting, it tells the hypothalamus (our thermostat) that it should be set higher. So we feel cold (so we try to keep ourselves warm) and the body thinks it's cold (so it increases the temperature by burning glucose mainly)