I had this as a child and then I see the following quote and wonder if this has anything to do with my fibro today? Has anyone else had rheumatic fever? "The exact cause of rheumatic fever isn't clear. Medical research has focused on an abnormal immune system response to the antigens produced by specific types of streptococcal bacteria. In addition, researchers are studying whether some people have a greater genetic disposition for an abnormal immune system response to streptococcal antigens."