Serum and synovial oncostatin M and leukemia inhibitory factor in rheumatoid and osteoarthritis

ABSTRACT

To measure levels of oncostatin M [OSM] and leukemia inhibitory factors [LIF] in the serum and synovial fluid of rheumatoid arthritis [RA] and osteoarthritis [OA] patients. Also, to correlate their levels with the parameters of disease activity in RA and severity in both RA and OA. This study was conducted on 20 RA patients, 10 OA patients and 10 healthy controls. Serum and synovial fluid levels of both OSM and LIF were measured using quantitative sandwich enzyme immunoassay technique. The mean levels of serum and synovial OSM as well as LIF were significantly higher in RA patients than controls [30.3 +/- 14.5, 252 +/- 117, 23.5 +/- 5.2, 41.8 +/- 7.2 pg/ml respectively, p<0.001]. Similar findings were also detected only in synovial OSM and LIF of OA patients [39.5 +/- 4.8, 22.4 +/- 4.5 pg/ml respectively, p <0.001]. On comparing RA and OA patients, there was a highly significant increase in the serum and synovial OSM as well as LIF in RA patients [p <0.001]. Also, there was a highly significant correlation between the serum and synovial OSM in RA and OA patients. Similar findings were found between synovial OSM and LIF as regards the activity score, total number of WBCs and ESR. Stepwise multiregression analysis revealed that serum LIF and ESR were the best parameters to discriminate patients with more active RA. On the other hand, serum OSM, peripheral WBC count and synovial LIF were the best parameters to detect the severity of the disease. Our results confirm the role of both OSM and LIF as important factors that mediate the pathophysiologic events in RA, besides their role in detection of activity of RA and severity of both RA and OA