It is sort of sugar
I have the press release about this, but I am too tired to look for it right now. If I recall correctly, it was not that there was a sugar molecule to be isolated out of the Ig. Instead, it was that a particular type of sugar linkage within the Ig caused the Ig to act as an anti-inflammatory agent.
It was pretty interesting at the time. I suspect that we haven’t heard much because isolating the Ig with that particular sugar is very hard and they have not had much success yet. Even if they do figure it out soon, it will take years to scale the isolation process up to commercial quantities and make it through the FDA approval process. Still, it is good to know that treatments will get better in the next decade or so, even if we don’t arrive at a cure.