Citrulline Arginine Anti-citrullinated<unk> <unk> es (ACPAs) are autoantibodies <unk> es to an individual's own<unk> s) that are directed against peptides and<unk> s that are<unk> . They are present in the majority of patients with rheumatoid arthritis. Clinically, cyclic<unk>  peptides (CCP) are frequently used to detect these<unk> es in patient serum or plasma (then referred to as anti–citrullinated peptide<unk> es). During inflammation, arginine amino acid residues can be enzymatically converted into citrulline residues in<unk> s such as vimentin, by a process called citrullination. If their shapes are significantly altered, the<unk> s may be seen as antigens by the immune system, thereby generating an immune response. ACPAs have proved to be powerful biomarkers that allow the diagnosis of rheumatoid arthritis (RA) to be made at a very early stage. In July 2010, the 2010 ACR/EULAR Rheumatoid Arthritis Classification Criteria were introduced. These new classification criteria include ACPA testing, and overruled the "old" ACR criteria of 1987 and are adapted for early RA diagnosis.
Anti–citrullinated protein antibody
Anti-neutrophil cytoplasmic antibody
Anti-nuclear antibody
Anti–Saccharomyces cerevisiae antibody
Antisperm antibodies
Rheumatoid factor
C-ANCA
ANA-12