I am not a biologist, but recently while reading an article on Scholarpedia about self-organization I encountered a fascinating biological observation concerning immune response to infections. To quote the article:
Whether the resulting patterns are stable or oscillating depends on the relation of the time constants. If the antagonistic reaction has a longer time constant than the self-enhancing reaction, oscillations or burst-like activations will occur. An example is the time course of an infection: The infection with few viruses could be sufficient to trigger a sickness since the viruses replicate themselves (self-enhancement). The antagonistic reaction, mediated by the immune system, is much slower. It takes a day to become sick, but a week to become healthy again. (What appears on a first inspection as a disadvantage is in fact a good strategy. If the immune system would be much faster, an equilibrium between virus production and virus removal would be established. After a single infection we would fight for the rest of our life against the virus. However, due to the burst mode, we become sick for a short while but the virus is subsequently completely eliminated).
Since the quote may be hard to parse out of context, I'll recapitulate: The writer is asserting that the immune system's response to infections is slower than might be physically possible because such slowness actually makes the response more effective. By waiting a few days, the patient is sick for longer than they might be happy about, but when the infection goes away, it's gone for good. If the immune system responded immediately to an infection, it might result in a low-level infection that persists indefinitely.
This makes me wonder: For chronic diseases, is the reason they are chronic related to the time scale of the infection vs. that of the immune system's response? Could such diseases possibly be cured by suppressing the immune system for a time so as to get the "burst" effect alluded to in the quote above?