Table 1.

Source and characteristics of fibroblasts used for mRNA quantification

Source of isolated cells	Number of patients	Method of cell isolation	Median no. of passages (range)
Rheumatoid arthritis (synovial membrane)
Primary culture	5	Collagenase digest	0
Passage ≥ 5	7	Tissue outgrowth	9 (5–14)
Foreskin (normal skin)
Primary culture	6	Collagenase digest	0
Passage ≥ 5	6	Tissue outgrowth	5.5 (5–13)