I'm not sure how much input you have into what tests you can get done, but I would be looking at getting more intensive immune system, liver function tests, etc, than are done normally by doctors. For example, most doctors would just test the immune system by doing a blood test and checking levels of white blood cells or other immune numbers. While this checks the levels of your immune defence, it would not show if your immune system is over-reacting, or auto-immune. More extensive tests are out there, such as testing levels of pro-inflammatory immune chemicals, such as cytokines. I would also test liver function, digestive system and for oxidative stress. But the choice is prob not in your hands. Good luck with this.