Congratulations Jem. You must be the first person in the world who has been cured!
Seriously though, it seems like what he might have meant to say is that your Lupus is in remission. That can happen - all signs and symptoms can disappear and some people do indeed come off all medications. Others here on the board reported that they had long periods of remission but that Lupus came back at some point with a vengeance.
Are you feeling well with no symptoms? What is he he basing his assessment on?
Lupus is an incurable illness so its not something that can suddenly disappear. It may lie dormant but there is always the possibility that it comes back for another go.
If indeed he takes you off the Plaquenil next year and everything has been going okay up til then, make sure you have a plan of action with him should your symptoms return. I would also have a talk with him about what he means when he says your Lupus is 'gone'.
Best of luck and I hope it lasts a long time
Joan:rose: