Immunity: the inside connection

One advantage of living near Washington DC is the Smithsonian Resident Associate Program. I’ve gotten to hear people like novelist John Mortimer, historian John Keegan, DNA co-discovered James Watson, and nanotube expert Richard Smalley.  Some weeks ago it was Jan Moynihan on “Making Connections: the Endocrine and Immune Systems and the Brain.”

I don’t have any formal background in science, so a good deal of the time I was swimming (or dog-paddling) in water over my head. (And mighty polysyllabic water at times: “a chronic increase in proinflammatory cytokines can induce a state of resistance to anti-inflammatory glucocorticoids.”)

Moynihan’s main topic was the link between the immune system and the brain. Each influences the other. This sounds straightforward — but for centuries “common sense” told people the earth was flat. Moynihan provided evidence for the connnection… and some possible implications as well.

For example, one study showed that exposure to acute stress prior to a flu vaccination enhanced the body’s ability to create antibodies — but only in women. ( “Acute stress” here means a brief, one-time experience, such has having to subtract backwards from 1,000 by 17.)

Working on Project Allostasis

Chronic (long-term) stress produces what’s called allostatic load. “Allostatic” refers to the body’s complex balancing act. If you’re walking in the desert, you’re stressed by the head. The body could sweat, but eventually you’d dehydrate. So rather than that simple, homeostatic adjustment, the body will reduce urine output, dry out mucous membranes, decrease sweat output, constrict the circulatory system in order to maintain blood pressure with a lower volume…

An increased allostatic load can have negative consequences:

  • Impaired cognitive function
  • Suppressed thyroid function
  • Decreased bone density
  • Decreased muscle mass
  • Higher blood pressure
  • Decreased adaptive-immune function

That last point reference to the adaptive immunity you’ve acquired — e.g., through vaccinations.

In other words, chronic stress can reduce your body’s ability to protect itself.

This was a summary of a complex field, but at least for me, one worth tracking.

Stressful work photo by alexanderljung / Alexander Ljung.