jft,
Steroids suppress the immune system = true (they are not solely immunosuppressants though, they are mainly anti-inflammatory drugs), however...the longterm side-effects of steroids (bone thinning, glaucoma, diabetes, stomach ulcers, thinned skin, high blood pressure, edema, etc...) are far worse for the body than the long term side-effects of immunosuppressants. It is best, as per every hepatologist in this country, to start immunosuppressant therapy along with the steroids. Once the liver function tests improve, the steroids can slowly be weaned off. I am only on Imuran currently (an immunosuppressant) and I am only mildly immunosuppressed. So not enough that my blood counts are bad but enough that my immune system is not causing further attack on my liver. The art is figuring out the right dose for each patient so that our immune systems stop attacking us. The steroids help but primarily to stop the inflammation caused by the attack.
In the end, it is up to the doctor to decide the appropriate course of treatment for each patient based on severity of disease, biopsy, response to steroids, etc...However, we are responsible for ourselves and need to stay informed on what options are out there in case we prefer trying a different approach.
Is your wife also on a proton pump inhibitor of some sort? That's something to keep her stomach lining protected from the steroids...like Protonix, Aciphex, Prevacid etc...I don't know the names of those overseas but you'd be able to find out on Wikipedia.