Autoantibodies to Malondialdehyde-Acetaldehyde Are Detected Prior to Rheumatoid Arthritis Diagnosis and After Other Disease Specific Autoantibodies.

IgG and IgA anti-MAA autoantibodies are elevated prior to RA diagnosis but appear later in the preclinical course than anti-CCP-2 or RF. These findings suggest that MAA formation and anti-MAA immune responses could play a role in the transition from subclinical autoimmunity to clinically apparent arthritis.