VALUE OF SYNOVIAL-FLUID INTERLEUKIN-1-BETA DETERMINATION IN PREDICTING THE OUTCOME OF PSORIATIC MONOARTHRITIS

Objective-To investigate the value of synovial fluid analysis in predi cting the outcome of psoriatic monoarthritis. Methods-In synovial flui d from knee joints of 18 patients with psoriatic monoarthritis lasting less than six months, white Mood cell count, acid phosphatase, lysozy me, and interleukin (IL)-1 beta were determined. ESR and serum C react ive protein were also measured. To define the outcome, the patients we re monitored for at least three years and then subdivided into those w ith polyarthritis and those without. Results-Among the blood and synov ial fluid indices considered, synovial fluid IL-1 beta was the only va riable which differed between the patients who developed polyarthritis , within three years those without polyarthritis after time, at 20.82( SD 8.79) v 4.19(4.73) pg ml(-1), P < 0.0001). A correlation was found between synovial fluid IL-1 beta concentrations and the number of affe cted joints after three years (r = 0.739, P < 0.0001). Conclusions-Det ermination of synovial fluid IL-1 beta at disease onset may be useful in revealing the outcome of psoriatic monoarthritis since, among the v ariables considered in our study, this was the only one capable of pre dicting the evolution of monoarticular psoriatic arthritis to polyarth ritis.