I missed the window to upvote you, but I am following and will look up more current posts. I found you because I had a question about IgG4. I know very little about this immunoglobulin (correct terminology?). I noted that it is an element in a number of autoimmune diseases, so I started reading up on it. All my posts begin with a question, and you helped to answer this question today. Now I know IgG4 is an important part of the innate immune system and it is the only Ig to cross the placenta. I'm not sure what I'll do with that information, but it is interesting. Hope you read this, because the payout has expired. I'm on a science adventure lately, learning about all sorts of things. IgG4 is my most recent path. Anyway, thanks for the information. You really are in command of this material.