Progression of GBS with IVIg
Ali, the explanation you just gave that you learned at the conference definitely makes sense for my own experience. After beginning the IVIg treatment, I continued to get worse for another three days, and it wasn’t until my fourth day of IVIg treatment that I hit my nadir (the bottom of the U), and started getting better again. I have no doubt that without the IVIg, it would have taken longer for me to reach the nadir and start improving again, and subsequently a lot more damage would have occurred. It also makes sense in that plenty of people recover from GSB without IVIg, but often sustain worse damage and have longer recovery times. This, of course, is not counting all the other treatments that works very well too (PP, steroids, etc.).
Here’s another interesting little tidbit about IVIg that I just learned from my immunology lecture. When antibodies bind to our myelin, they form immune complexes that allow attacking cells of the immune system to target the myelin through special receptors. The large infusion of pooled human gammaglobulin that you get from IVIg causes a preferential activation of a special inhibitory receptor called FcgRIIB that is found on leukocytes (the attacking cells of the immune system). With this receptor preferentially activated, there is less activation of the attacking leukocytes. This means that there will be less tissue damage (i.e. the myelin will be less exposed to inflammatory chemicals and other types of damage usually inflicted by these immune cells). A different receptor, called FcgRIII, is the counterpart to the FcgRIIB receptor – when activated, MORE damage occurs. So you can see why a preferential switch to the inhibitory FcgRIIB receptor (as opposed to FcgRIII) is a good thing for GSB. They say some people with certain autoimmune diseases either have preferential activation of RIII, or else a complete lack of RIIB.
Sorry if that was a little heavy on the immunology lingo – really interesting stuff, and really helpful to understand why IVIg can work so well for some people (as it did for me).