An immunometric for the measurement of anti-PAD4 autoantibodies.

• Measure anti-PAD4 autoantibodies of any isotype (IgM, IgG, IgA)
• For use in human plasma and serum (no need to purify samples)
• Lower Limit of quantification is 31,3 U/ml

PAD4 is a guanidino-modifying enzyme which catalyzes the conversion of specific arginine residues to citrulline in a calcium-dependent manner. PAD4 activity is increased in rheumatoid arthritis (RA), producing citrulline-containing proteins (CCP) that induce the formation of arthritogenic autoantibodies.

In addition to anti-CCP autoantibodies, 23 to 45% of RA patients also produce autoantibodies specific for the PAD4 enzyme itself. PAD4 Autoantibody ELISA Kit is an immunometric assay which can be used to measure anti-PAD4 autoantibodies of any isotype (IgM, IgG, and IgA) in human plasma and serum without prior sample purification.

Affinity-purified anti-PAD4 antibody isolated from the plasma of a patient with RA is used as the standard. One unit is approximately equal to 1 ng of anti-PAD4 Ig protein.