I don't know, because there's nothing wrong with my immune system normally. It's only when I drink coffee regularly that I crash. Maybe something to do with caffeine crashing my adrenals, which then pulls down immunity?
I crashed with candida once in 2010, pretty much healed myself after about a year, felt so much better that I started drinking coffee every morning again, then crashed much worse than even the first time. So in my case I know for sure that coffee is my trigger.