I personally do not know of any type of research center devoted JUST to Polymyositis. I am aware of the Myositis Organization---they can point you in the right direction. The MDA is also pretty knowledgeable in Polymyositis. For me, it was a relief to FINALLY have just one doctor KNOW what I was dealing with.
Do not meddle in the affairs of Dragons, for you are crunchy and taste good with ketchup.