More details on them here: http://tamtrible.livejournal.com/169138.html
I need an immune condition for patient zero, so that my zombie fungus can evolve. Ideally, I'd like one where she, previously, had periods of extremely depressed immune response (particularly with regards to fungi), then periods of relatively normal immune function. I'd like her to have had several such episodes--ideally, something like immune function that's on and off (at least wrt fungi) for several months at a time, for several years. Essentially, I'm looking to evolve behavior of "hide in brain when there's an immune system, and grow when there's not", and I figure I have the best chance of that with alternating periods of "fungal free-for-all" and normal immunity.
I looked up "variable immune deficiency"... this doesn't quite sound like what I want, since it sounds like it doesn't have the dynamics I need, but it's all that's coming up.