Difference between PSC and AIH/PC

On this thread http://www.livingwithpsc.org/forum/topic/show?id=6288168%3ATopic%3A44690 jtb said:

AIH/PSC overlap is a bit of a different animal than plain PSC. People with AIH/PSC overlap tend to last a lot longer before needed transplant when compared to plain PSC patients. This is mainly because there is a non-transplant treatment plan for AIH/PSC (corticosteroids, immunosuppression, and Urso) where there is no consensus on an effective treatment plan for plain PSC. All in all, the outcome with AIH/PSC is generally better than with PSC alone.

I have AIH/PSC overlap. Up to the point I read jtb's comment today I had been thinking of it as simply two separate liver diseases that I have going on at the same time. But this makes it sound like AIH/PSC is really its own thing.

Also, regarding jtb's comment that the non-transplant treatment plan for AIH/PSC, my Dr talks about treating AIH and PSC separately. Immunosuppressants for the AIH, and no treatment, just regular scanning and ERCP as needed for the PSC.

Can anyone point me to discussions about the differences? I want to understand this better.

Here's a good background on overlap syndromes: http://omicsonline.org/orgoverlap-syndromes-of-autoimmune-liver-disease-2155-9899.1000161.pdf

The International AIH Group does not officially recognize AIH/PSC as being a unique disorder and they view it, particularly from a diagnostic standpoint, as the AIH and PSC being separate conditions. That said, they recognize that the treatment of PSC in the presence of AIH is different than it would be if there was no AIH present. AIH therapy tends to also help the PSC when AIH is present but does nothing when PSC is the only condition.

My son has this overlap. Apparently it is more common in pediatric cases than in adult. I didn't know that the expected time to transplant was different between ASC and PSC solo. However, the immunosuppression he is on for the AIH is helping the UC. If/when he stops that (1-3 years we were told, depending on response, and he's now at 18 months) something will likely be needed to be added to control the UC.

Thanks, jtb. The article you pointed me to is interesting, but it mostly it says to me that there's no really clear understanding of what the differences are. I do see toward the end where it does suggest that AIH/PSC does have a better outcome than PSC alone, and that is good to hear.

To mom to psc teen: I had colitis from 8 years old, and it is rough for a kid. I hope you're giving him lots of emotional support, that's something that I didn't have and needed more than anything. Not only the illness, but also the treatment and tests are painful and unpleasant and it was hard for me to understand why I had to do that stuff. My heart goes out to you and your son.