Brad,
I hope you're sitting down when you read this (b/c most people go into shock) but I received a heart/double lung transplant 15 years ago (June 14, 1996) when I was 16 years old. To make a long story short, yes I was born with a bazillion health problems (premee + under developed lungs + inoperable holes in my heart = transplantation as a teen) and I've only experienced one bout of rejection. It was in 2006, chronic, and it was in my lungs. But yours truly fought back and I've been able to keep it at bay for 5.5 years.
Oh, and I don't know who my donor is but I have written to the family twice, to no avail. Ah well. Sucks but what can you do?
And AWESOME at the kidney donation! You're someone we recipients admire! I hope your brother is doing well. Maybe I'll see you both at next year's games! (Message me if you want more info!)