Figure 1.

Screen to identify undeiminated and deiminated proteins reacting with RA and non-RA serum samples. Proteins from HL60 lysates incubated (+) or without (-) peptidylarginine deiminase (PAD) blotted with an antibody specific for modified citrulline residues (anti-citrulline) and a screening panel of rheumatoid arthritis (RA1 to RA4) and non-RA (control) serum. The rectangular box indicates a citrullinated protein reacting strongly with each of the RA serum samples but not the control.