I also had increased liver enzyme levels while on Rebif and had to decrease the dose for about a month (I think) until the levels dropped back to normal. At the time I thought that this increase was due mostly to the oxazepam that I was taking at the same time as Rebif to help me sleep (known to possibly increase liver enzymes according to its monograph) but now I am not so sure. Interestingly, about six months later during a visit to my neuro, another doctor asked me if I would provide a blood test specifically to test for liver enzymes (ALT/ AST) because I was on Rebif. I didn't have the blood test because I had taken a 2-month break from Rebif, but it was an indication to me that they were looking at it more closely.
This happened about a year before Health Canada published the advisory about liver function and Rebif. It's posted here in the stories archives, I think.
So you're not the only one, in Canada at least, that has had the same adverse event.
All the best,