Its quite interesting there is no reply. I'm guessing and RF marker is not common place for CFS. Given elevated levels can mean a chronic viral infection I thought this might have been a key sign.
My rheumatologist treats many cases of RA and other with antibiotics. It's a treatment option that few doctors know about but it's been around for ages. Unfortunately drug companies have no interest in funding doctors training to let them know that you can treat somebody with a cheap generic prescription. So you only hear of expensive drugs that have quite harmful potential side effects and help with symptoms at best but do not resolve the underlying cause.
There are studies of autoimmune conditions like MS, ALS and RA induced by bacterial and parasitical infections like Mycoplasma, Borrelia, Chlamydia Penumonia. There are plenty of individual stories (just google it) of people that have regained functionality after treatment with antibiotics. I don't know whether viruses can do the same but I'd look into it if I were you.
I can't comprehend how doctors can completely overlook or ignore the presence of chronic infections in CFS particularly when there some autoimmune disturbance and even more so when the illness was triggered by some sort of infections in the first place. It's just beyond me.
I'd commend the book Autoimmune, The cause and the cure, by Annesse Brockley. It's got a lot of helpful advice in it for autoimmune conditions. It looks at autoimmune disorders from a new different perspective but whether those can be cured for good I don't know.