Fibronectin molecular status determination useful to differentiate between rheumatoid arthritis and systemic lupus erythematosus patients

Abstract To find whether the plasma fibronectin (FN) molecular status can be useful to differentiate between rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). The expression of plasma FN domains was determined by ELISA using monoclonal domain-specific antibodies. FN molecular forms were revealed by immunoblotting and analyzed by densitometry. The following findings were found: (1) Mean values of Fibrin–HeparinFN concentration were lower in SLE and RA patients than in normal plasmas. The cut off points at 31 mg/l in SLE