Validation of Q-PCR in rheumatoid arthritis (RA) and osteoarthritis (OA) tissue. (a) IL-1β and (b) IL-6 expression in RA synovium. Nine RA and 13 OA synovia were biopsied at the time of joint replacement and were assayed by quantitative PCR using the cellular standard curve method. Data are expressed as relative expression units. The median is indicated and Student's t test was performed on log-transformed data.