The Relationship Between Serum Osteopontin And Disease Activity In Rheumatoid Arthritis And The Role In The Interstitial Pulmonary Fibrosis

Objective:In order to evaluate the role of osteopontin(OPN)level in the disease activity of rheumatoid arthritis(RA)and in the pathogenesis of Interstitial lung disease(ILD),the serum level of OPN and other in RA patients were investigated,and the relationship between OPN and other clinical and laboratory findings were analyzed simultaneously.Methods:The serum of 65 RA patients and 20 healthy controls were collected.Based on the activity index of RA,the 65 RA patients were divided to active RA group,inactive RA group and on the interstitial pulmonary fibrosis index,they were divided to ILD group,non- ILD group,and the RA with ILD group was divided to interstitial pulmonary fibrosis group,interstitial pneumonia group.Simultaneously,The clinical feature,laboratory index,the description of high-resolution computed tomography (HRCT)and the result of blood gas analysis,pulmonary function(%VC,%DLCO) were recorded at the time of peripheral blood sampling.The concentration of serum OPN in the RA patients and healthy controls was measured by enzyme-linked immunosorbent assay(ELISA).Results:(1)The concentration of serum OPN was significantly higher in RA patients than that in the healthy controls.(median:18.0ng/ml vs 14.3ng/ml,Z=-4.317,P=0.000＜0.01).(2)The concentration of serum OPN was significantly higher in the active RA patients than that in the inactive RA patients.(median:20.0ng/ml vs 16.5ng/ml,Z=-3.583,P =0.000＜0.01).(3)The concentration of serum OPN was higher in the RA patients with ILD than that in those without ILD(median:20.0ng/ml vs 17.0ng/ml,Z=-2.376,P=0.017＜0.05).(4)The concentration of serum OPN was significantly higher in the interstitial pulmonary fibrosis patients than that in the interstitial pneumonia patients. (median:21.5ng/ml vs 17.3ng/ml,Z=-2.909,P=0.004＜0.01).(5)The concentration of serum OPN in the RA patients showed a significant positive correlation with course of disease,tenderness numbers of articulation, erythrosedimentation(ESR),C-Reactive Protein(CRP),but no positive relationship was found with Hb,IgG,IgA and so on(P＞0.05).(6)The concentration of serum OPN in the patients with interstitial pulmonary fibrosis showed a negative correlation with the value of PaO₂(r=-0.503,P=0.012＜0.05),but no relationship was found with pulmonary function(%VC,%DLCO).(7)There is a significantly statistical difference in tenderness numbers of articulation,swelling numbers of articulation,erythrosedimentation(ESR),C-Reactive Protein (CRP)between ILD and non-ILD group;The concentration of serum RF(IgM)was higher in the patients with ILD than that in those without ILD.(median:278.2IU/ml vs 131.0IU/ml,Z=-2.250,P=0.024＜0.05).Conclusion:(1)The concentration of serum OPN in RA patients elevated compared to the controls, which suggested OPN may take part in the pathology of RA.(2)The concentration of serum OPN in the active RA patients elevated compared to the inactive patients,and showed a significant positive correlation with the active index such as ESR,CRP which suggested that OPN may be related with the activity of the disease,and may be a inflammation index of judging the activity of the disease.(3)The concentration of serum RF(IgM)in the patients with interstitial pulmonary fibrosis elevated compared to those without interstitial pulmonary fibrosis,which suggested RA with interstitial pulmonary fibrosis maybe more common in the patients with higher RF(IgM)level.(The concentration of serum OPN in the patients with interstitial pulmonary fibrosis elevated compared to those without interstitial pulmonary fibrosis,and showed a significant negative correlation with the value of PaO₂.which suggested that OPN may take part in the pathogenesis of RA with interstitial pulmonary fibrosis and be related with the severity of disease.