Wgtd's The Morning Show With Greg Berg

This is an interview with Pulitzer-Prize winning writer Matt Richtel,   author of "An Elegant Defense:  The Extraordinary New Science of the Immune System:  A Take in Four Lives."   The book explores the nearly miraculous capacity of our body's immune system to ward off all sorts of threats - but also how difficult life can be when the immune system, in one way or another, goes awry.