Klein, Alice Semen reshapes immune system to boost chances of pregnancy. New Scientist. August 26th 2016.
My first thought on reading the headline and blurb of this article of science news was that it explains the sex ratio and typical age of onset of the autoimmune disease lupus or Systemic Lupus Erythematosus (SLE) which typically affects women with typical ages of onset during the years between puberty and menopause, the childbearing years. There are also other autoimmune diseases that affect mainly women. Because of this pattern medicos have suspected a hormonal cause for SLE but as far as I know this theory has not gathered evidence. An alternative explanation would be that SLE is a harmful side-effect of a normal ramping up of the activity of a woman’s immune system during her reproductive years in anticipation of the immune-damping effects of heterosexual activity (not “safe sex” with condoms or barrier methods of contraception but sex as it was practiced in the times when the human immune system evolved). The normal lifestyle of early human female adults of reproductive ages would have included mostly years of pregnancy, breastfeeding and unprotected sexual activity. It is my understanding that pregnancy dampens the immune system to a degree, and it appears unprotected heterosexual activity also could do this for women. I have no idea about breastfeeding, but I know it alters the profile of reproductive hormones and can suppress ovulation. So it appears that the modern woman of reproductive years can be exposed to many years without the immune-suppressing activities that would have been a normal part of the lives of her distant ancestors, so it makes sense that this could elevate the risk of developing SLE or any of the huge range of other autoimmune diseases. Not all autoimmune diseases affect females preferentially, some affect males more, and these sex ratios are surely a clue to what causes them.
I apologize to any of my readers who might be jolted or offended by discussion of the above matters, but I think it is important to discuss scientific ideas about diseases that kill and harm many people. Please readers also remember, if my ideas expressed in this post or in my blog in general are original, or could be original, do not publish or re-use them as though they were your own original thoughts. I’ve had that done to me before by academics, and any such behaviour will be publicly highlighted and soundly criticized.