Hey, Whirlwind. I can never remember your "real" name!
ESR is one of the acute phase reactants. There are so many things that it can be from, such as inflammation, infection, and cancer.
http://www.aafp.org/afp/1999/1001/p1443.html
Do you have any new symptoms? Are you anemic? Do your doctors check a CBC periodically?
Since you're on immunosuppressants, your doctor should keep an eye on it.
I've had an ESR of 104, due to clostridium difficile. Anything over 100 is fairly serious. I've also had one of 68 where nothing could be found and then it went back to normal.
60 could simply be inflammation, as Sue said.
MG isn't an inflammatory disorder, so it wouldn't affect an ESR. I haven't found any articles that would indicate that.
Watch for any new symptoms, and maybe recheck it in a few months. I can't remember if you've had a thymoma or not. Does your doctor think that you are a cancer risk? Does cancer run in your family?
Trust your instincts and go in if anything new pops up.

Annie