Upon first learning my daughter’s type 1 diagnosis, I felt despondency laced with guilt. ‘Oh great’, I thought ‘she’s inherited my crappy genes’ (I’m LADA diabetic). And while we are primarily concerned about her health in the near-term, I can‘t help but worry about social stigma that might hamper her success in the future. Many out of hand believe autoimmune issues signal some kind of defect. Yet, there is strain of thinking, which maintains the opposite.
We might consider autoimmune conditions as something akin to obesity. Where in past leaner times the ability to hoard away as many calories as possible would have been a positively selected for benefit, that same trait in today’s world of plenty can prove a liability. In the light of the hygiene hypothesis something similar could be going on with the rash of autoimmune disease we see in our modern clean world. The hygiene hypothesis at root attributes the spate of autoimmune disease to an overly clean world where the immune system not properly primed by germs, malfunctions and turns against itself. A corollary to this is that those genes which predispose one to be at risk for autoimmune conditions when trained properly actually confer a survival benefit! That is for most of the time humans have been on this planet we lived in primitive conditions surrounded by many germs, and the ‘autoimmune’ genes interacting with various microbes throughout prehistory helped our ancestors to survive and so they passed these genes along. Unfortunately, in today’s overly hygienic world the untrained autoimmune genes become like an unused rodent’s tooth that continually grows until damaging the host. There is evidence for the hygiene hypothesis even in the present day. For example, if you look at relative rates of allergies and asthma in urban kids they are significantly higher than their rural counterparts. Of course, both groups are relatively clean by primitive standards, but the city kids get far less exposure to germs.
With all that in mind one must wonder what the proper course of action is to turn the tide on the ever growing problem of autoimmune disease. Are we supposed to go hiking and hunting with bows more often? Roll around in the mud first to create camouflage so our prey doesn’t see us? While that may indeed help, it could also lead us down a path of having to battle with other deadly pathogens. A better answer may lie in reintroducing the TB vaccine BCG. The TB mycobacterium which it protects us from has one of the oldest relationships of co-evolution to our species. And numerous scientific studies show that BCG administration benefits trained immunity as well as mediating improvements in autoimmune conditions like MS and Diabetes. As Dr Thomas Dow once stated so succinctly when talking about the lack of old friends (germs) in his paper on proposing BCG vaccination, ‘for those who had little exposure to the Old Friends, they may find a friend in BCG.’