I think there's also a big difference between supplements that boost the immune response overall, and those that are more targeted to support only certain aspects (in particular natural killer cell function, and the other stuff that seems to be consistently messed up in ME/CFS patients).
I take all supplements with caution and a close eye on the effects, because I think we're all so fragile that just about anything could be tough on us. I think I'm one of the people who seems to be helped by immune modulators that support Th1 function, though, so I'm still planning to go ahead and explore those further. I tend to feel like if it makes a person feel better, take it. If it feels worse, try to figure out why and consider whether it might be better to stop (obviously some things that are quite helpful in the long run can have rough patches or detox associated with them and are often worth persevering with). The new info will make me a little extra aware, but doesn't change my plans at all really. We already knew that parts of our immune system were overactive, right?
That said, I would avoid indiscriminate immune boosters (I try to stay away from echinacea, etc.). But I was already leery of those in case they made the Th1/Th2 problems worse. Then again, I know that some people on here have taken them and liked the results. So who knows.