**3.1.1 Fibroblast-like synoviocytes (FLS) culture**

Synovial tissue specimens were collected under sterile conditions from 6 patients with RA. Specimen collection occurred during total knee arthroplasty in all patients with RA. All RA patients fulfilled 1987 American College of Rheumatology criteria for RA. All of them were treated with only NSAIDs, DMARDs and hyaluronic acid injection into the joint before samples were obtained. The methods of FLS culture was described previously (Nanki, et al., 2001).
