Severe Spinal Inflammation

I have Fibo, I have Hashimoto's Thyroiditis and I have also been being treated for Sero-Negative Rheumatoid Arthritis...  Sero-Neg RA meaning that I am treated for symptoms of RA, yet antibodies never found in my blood.
I was told that 30% of RA patients are treated for symptoms yet RA is never confirmed through their blood.  

Treatment for RA, I had been taking Methotraxate, Plaquinal, Sulandac until 8 weeks ago. Until I had a Complete Thyroidectomy.

The last time I had a visit with my (new) Rheumatologist, he told me that Rheumatoid usually doesn't cause spinal inflammation.  I have inflammation in other areas too, but mostly in my spine.  

I see my Rheumatologist tomorrow....  He now want me to try bi-monthly infusions of Remacade.

I have been tested for Ankly Spondalitis (No bridging show in my MRI), Psoriactric Arthritis (NO gene marker), and RA.

I am still not sure that I indeed have RA for I am Sero-Neg, and most of my inflammation is in my spine, I also often have swollen hands and feet.  What other auto-immune disease causes "Spinal Inflammation"?

Any ideas?

Sonflower