Anthropology

that autoimmune diseases are our homo sapiens immune system rejecting our neanderthal cells.
they coexist fine until viruses or pregnancy fire up the immune system.

i have several myself. they are all over my family. us gingers are the sickest.
i had 6 pregnancies, and most viruses, starting as a baby. i got west nile in '02, and i have been sick ever since. i think i got a mild case of ms then. but have also recently been dx'd as diabetic, and it has been cooking for several years now.
also have shogrens, which impacted my youngest as a fetus.
that kid has ehlers-danlo 2, and unexplained liver issues.

i think eventually we will find that there are similar proto human genes in ppl from other parts of the globe, and that similar conflicts arise in those that have similar holdover genes.