I Have A Question About A Specific Drug Interaction With

I have a question about a specific drug interaction with an herb. The drug is cyclosporine used as an anti-rejection med for a liver transplant. The herb is St. John's Wort, which my Internal Medicine doctor told me is the basic ingredient in the antiviral Entecavir. Is there a possible negative effect between cyclosporine and St. John's Wort, in the absence of Entecavir? Thanks for your consideration.