im still trying to get my head around xmrv being both glucocorticoid response element and androgen response element. i can understand cortico side of it as it is activated during times of stress and has the ability to lower the immune system but androgens sort of have an opposing effect to cortico steroids. The only thing i can think of is that androgens(testosterone) have a growth promoting effect on some tissue, especially muscle. I know in HIV patients that muscle wasting is a big problem and anabolic steroids(which are androgens) are used to stop muscle wasting effects of the disease, but they have also found that anabolic steroids enhance the immune system. In my weight training days i was intrigued by anabolic steroids and did some research on them. I remember reading an article on east german athletes how they would often get sick coming into competitions and this was thought to be due to anabolic steroids. The east german scientists looked into this further and found that anabolic steriods enhanced their immune systems and what would make them prone to infections etc prior to competition was that they would stop steriods so many weeks to test negative in drug tests, so their own androgen levels would drop below normal and weaken their immune systems. Normally androgen levels are higher then cortisol levels and help keep them in check but when on androgen therapy and it is suddenly stopped, cortisol levels become higher then androgen levels and cortisol becomes the dominant hormone, making them feel crappy, weak and prone to infections, flu's etc. In saying all this, which mainly to do with males, females would obviously react differently. Before all the xmrv stuff was about, i was thinking having high normal testosterone levels would be a good idea for increasing immunity, nk cell function etc. At the moment i have these ideas on hold.