INTRODUCTIONOsteoarthritis (OA) is a progressive degenerative disorder of the articular cartilage. Available diagnostic radiography has been poorly associated with the progress and severity of this clinical disease. As osteogenic protein-1 (OP-1) has been identified as a bone morphogenetic protein with a major role in cartilage repair, we aimed to evaluate its potential role in the diagnosis of OA.

METHODSThis was an experimental study conducted at the Department of Biochemistry, Sikkim Manipal Institute of Medical Sciences, India. Polyclonal antibodies (i.e. anti-OP-1[f]) were raised against OP-1 in mice, and subsequently used in a sandwich enzyme-linked immunosorbent assay (ELISA) to detect the presence of OP-1 in the synovial fluids of 75 osteoarthritic patients. For the purpose of correlation, the radiographic assessments of the knees of the 75 patients were graded using the Kellgren-Lawrence scoring system.

RESULTThe polyclonal antibody (i.e. anti-OP-1[f]) raised against OP-1 was able to detect the presence of OP-1 in the synovial fluids of all the osteoarthritic patients via sandwich ELISA. The level of the OP-1 was found to be much higher than the reference range and correlated positively with the severity of OA (r = 0.24; p = 0.04).

CONCLUSIONOur study shows that the polyclonal antibody, anti OP-1(f), could be used for the immunodiagnosis of osteoarthritis via sandwich ELISA.