Most microbes, including Mycobacterium tuberculosis, cunningly employ
immune evasion tactics which thwart and disrupt the normal functioning of the immune system. Microbes use immune evasion in order to stop the immune system from attacking and destroying them.
If it were not for these immune evasion tactics used by microbes, chronic infections would not exist, and without chronic infections, it is likely none of us would have CFS.
Mycobacterium tuberculosis deploys a number of immune evasion tactics to screw up our immune systems, and in particular, as the above article indicates,
this bacterium uses an immune evasion tactic that switches off our intracellular immune response (our Th1 mode), and instead switches on our extracellular immune response (Th2 mode).
Th1 is the right mode to fight this bacterium, and Th2 is the wrong mode. So by switching off Th1, and switching on Th2, Mycobacterium tuberculosis is able to evade our immune system.
Immune evasion is great for microbes, terrible for us.