Few studies have reported a possible involvement of pleiotrophin (PTN) in the pathophysiology of osteoarthritis (OA) and very little is known about its role in rheumatoid arthritis (RA). This study is to measure PTN in the sera and synovial fluids in RA and OA and to assess its relation to activity, functional class and radiological staging.
Serum and synovial fluid samples were collected from 35 RA patients and 40 knee OA patients and serum samples were withdrawn from 20 healthy controls. Demographic, clinical and serological data were prospectively assessed. Functional and radiographic grades were also assessed. Serum and synovial fluid PTN levels were measured using enzyme-linked immunosorbent assay (ELISA).
There was no statistical significant differences (p > 0.05) on comparing the mean PTN level in sera of RA, OA patients and healthy controls. However the mean synovial fluid level of PTN in both patient groups was significantly higher than mean serum level (p < 0.001). Significant correlations between the serum PTN level and both morning stiffness duration (p = 0.008) and mHAQ score (p = 0.039) were only observed in RA patients.
Our results point to a possible important role of PTN in RA and OA. We firstly report a serological pattern of PTN in the sera and synovial fluids of RA patients. However its implementation as a disease marker or a potential target therapy in both diseases awaits larger studies and further investigations.