Antimouse antibodies anyone??

Hi- I have been on Remicade for about 1 1/2 years and had been taking 6MP until about 3 months ago. I had asked my MD if I could stop the 6MP because I didn't want to be taking "all the meds." I started having severe joint pain in January and have since been diagnosed w/ Rheumatoid Arthritis. My rheumy sent some lab work away and found that I have a high level of human anti mouse ab in my blood from the Remicade. I have been started on MTX and my last Remicade infusion was postponed for a month. He says the MTX will bring the anti mouse proteins down. I wonder if going off the 6MP caused me to develop the antibodies against the Remicade? I am nervous about getting my next infusion because of the possibility of having a reaction to the Remicade w/ the anti mouse antibodies in my blood! Is anyone familiar w/ the test CCP (Cyclic Citrullinated Peptide Ab) My rheumy told me that this was a test specific for RA, and that RA is the only thing that could cause it to be positive. I read online that it can be positive w/ other autoimmune diseases also confused and since I have Crohn's colitis I wonder if it could have been positive from that! Well I guess I'm just confused, I had never had so much joint discomfort before so it would make sense that it could be RA. I have been in remission w/ my Crohn's since I started my Remicade infusions so I wasn't having joint pain because of a flare up from that (I don't think). If anyone has any insight on this I'd appreciate it! Thanks, AKG