Really fascinating...yeah unbelievable, do you know the author?? He called you right back,, very nice.
A couple other thoughts ( I liked your synopsis better than the article's) I like the fact AT3 levels drop in DIC.. it does not rule out the possibility that AT3 deficienct contributes to the problem...It's getting used up.... the other not stated in the paper but which can be guessed...is the signal molecule is thrombin or a close relative. My guess is where there is thrombin,,, there is also AT3.
As you probably notice I like AT3 in a bunch of conditions. I could be dead wrong, but I think it is not too farfetched to think the bodies approach to a number of systems controls is to use serine proteases and protease inhibitors to regulate activity.