What is the significance of Anti-CCP (Anti-Cyclic Citrullinated Peptide) antibodies?

From the Guidelines

Anti-CCP (Anti-Cyclic Citrullinated Peptide) antibodies are a highly specific and useful diagnostic marker for rheumatoid arthritis, with a pooled specificity of 0.96 (95% CI 0.94–0.97) and a diagnostic odds ratio of 43.05 (95% CI 32.00–57.93) compared to the reference standard 1. The significance of Anti-CCP antibodies lies in their ability to help diagnose rheumatoid arthritis, particularly in its early stages. Some key points about Anti-CCP antibodies include:

• They have a high specificity, making them useful for confirming a diagnosis of rheumatoid arthritis
• They can be used in conjunction with other diagnostic criteria, such as clinical symptoms and radiographic evidence, to estimate the risk of developing persistent or erosive irreversible arthritis
• The presence of Anti-CCP antibodies can help guide treatment decisions, including the use of disease-modifying antirheumatic drugs (DMARDs) and biological treatments
• Measuring Anti-CCP antibodies can be considered in people with suspected rheumatoid arthritis, as recommended by nice guidance 1 The use of Anti-CCP antibodies in diagnosing rheumatoid arthritis is supported by evidence from various studies, including a 2024 review published in Clinical Microbiology Reviews 1 and a 2007 report from the European Standing Committee for International Clinical Studies Including Therapeutics (ESCISIT) 1. In terms of clinical practice, the measurement of Anti-CCP antibodies can be a valuable tool in the diagnosis and management of rheumatoid arthritis, particularly when used in conjunction with other diagnostic criteria and treatment strategies 1.

From the Research

Significance of Anti-CCP Antibodies

• Anti-CCP (Anti-Cyclic Citrullinated Peptide) antibodies are significant serologic markers for diagnosing rheumatoid arthritis (RA) 2, 3, 4.
• These antibodies have high specificity and are present early in the disease process, making them useful for early diagnosis and predicting severe disease and irreversible damage 3, 4.
• Anti-CCP antibodies are more specific than rheumatoid factor for detecting rheumatoid arthritis, with a higher specificity of 95.9% and 97.9% for other rheumatic diseases and chronic inflammatory disease patients, respectively 4.

Diagnostic Performance

• Studies have shown that anti-CCP assays have good analytical and diagnostic performances for diagnosing RA, with sensitivity and specificity ranging from 63-97.2% 2, 5.
• The area under the curve (AUC) values for anti-CCP assays have been reported to range from 0.888 to 0.914, indicating good diagnostic performance 2.
• Different anti-CCP assays have been compared, and while they show good agreement, some differences in diagnostic performances have been highlighted, especially for certain assays 5.

Prognostic Capability

• Anti-CCP antibodies have been shown to be useful in predicting severe disease and irreversible damage in RA patients 3, 4.
• The titers of anti-CCP antibodies may also be early predictors of the efficacy of anti-TNF therapy 4.

Specificity and Sensitivity

• Anti-CCP antibodies have been found to be citrulline-dependent in most non-rheumatoid arthritis rheumatologic disease sera, but citrulline-independent reactivity can occur in some patients, particularly those with autoimmune hepatitis type 1 (AIH-1) 6.
• The sensitivity and specificity of anti-CCP assays can vary depending on the assay used and the population being tested, but overall, they have been shown to be highly specific and sensitive markers for RA 2, 3, 4, 5.