When I spoke of the immune system, I was referring to your mlcer. Your mlcer is going to experience some illness, as well as aches and pains. You, too, will experience health issues if you don't take care of yourself, but your mlcer is the one that will think that she has some series issues...but she may deny the fact that it's stress and/or depression.
Her childhood issues may not be something she has talked about. Her controlling mother may have stunted her emotional growth at an early age. She may have been ignored, treated as an after thought, not recognized for her accomplishments, encouraged, emotional abuse and/or physical abuse.
Your wife has gone back to the time that she was emotionally stunted and will need to revisit that time, figure out that she was not responsible for what transpired in her life, accept that she wasn't at fault and then grow up. Until she does, you've got to let her be and turn the focus back on to you and your family.
Here is a recent link to a thread on depression and mlc: