LAUSR

Background First degree relatives (FDR) of RA are known to have increased risk of developing the disease. The detection of altered bone metabolism in FDR could be a predictor of the preclinical phase of the disease. Objectives To study osteopontine (OPN) and osteoprotegrine (OPG) in FDR of RA patients as markers of altered bone metabolism in relation to clinical manifestations, inflammatory and RA seromarkers. Methods 55 persons were included, divided into 20 RA patients, 25 FDR of RA patients (without evidence of arthritis) and 10 healthy matched controls. Clinical evaluation, with emphasis on joint symptoms and signs was done for all, in addition to measurement of ESR, CRP, RF, anti-CCP, serum OPN and serum OPG. Results Mean ESR was significantly higher in RA (64.15±34.29) than in FDR (15.6±11.04, p≤0.001) and controls (6.0±2.05, p≤0.001) and significantly higher in FDR than controls (p=0.001). Mean CRP was significantly higher in RA (26.38±29.14) than FDR (5.99±5.08,p≤0.001) and controls (2.02±0.53,p≤0.001) and significantly higher in FDRs than in controls (p=0.011). Mean RF and anti-CCP were statistically higher in RA than in FDR and controls. Mean anti-CCP was higher in FDR than in controls but without reaching statistical significance while there was no difference regarding mean RF between FDR and controls. OPN was higher in RA (3.66±4.20) than in FDR (1.97±1.04) and controls (2.81±1.31) without statistical significance (p=0.102). While OPG was significantly higher in RA (143.89±365.47) than in both FDR (22.23±65.73, p=0.009) and controls (6.20±12.43, p=0.003). Mean serum OPN in RA was higher in RF and CCP positive (3.77±4.43 and 4.13±3.48 respectively) than RF and CCP negative (2.65±0.35 and 3.58±2.58 respectively) but without reaching statistical difference. Mean serum OPG in RA was higher in RF and CCP positive (153.15±384.64 and 161.78±394.67 respectively) than RF and CCP negative (60.50±85.56 and 42.47±68.09 respectively) but without reaching statistical difference. 8/25 (32%) FDR had arthralgia while 17/25 (68%) FDR were asymptomatic. FDRs with arthralgia had significantly higher ESR (27.88±11.22) and CRP (10.36±5.21) than asymptomatic FDR (9.82±4.13, p=0.003) and (3.93±3.58, p=0.003) respectively. OPG was higher in FDR than in controls and higher in those with arthralgia (51.55±114.68) than those without (8.44±9.67) but without reaching statistical difference (p=0.314). Similarly, serum OPN was higher in FDR with arthralgia (2.09±1.19) than asymptomatic (1.70±0.55) but also without significant difference (p=0.620). Furthermore, mean RF and anti-CCP were higher in FDR with arthralgia but didn’t reach significant difference. Conclusions OPN and OPG are markers of altered bone metabolism in RA. Their elevation in FDR than controls denotes a state of altered bone metabolism. Moreover, FDR with arthralgia experience higher levels of OPN, OPG, ESR, CRP, RF, and anti-CCP than asymptomatic FDR. These findings reflect an ongoing disturbed bone metabolism and inflammation in FDR which could precede the clinical disease phase. Thus, OPN and OPG could serve as markers of altered preclinical bone metabolism in rheumatoid FDR. Results need to be confirmed on larger numbers of FDR. Disclosure of Interest None declared