The Role of Anti-Cyclic Citrullinated Peptide Antibody From Joint to Brain



Meamar R¹ ; Maracy M² ; Ghasemi M³ ; Salesi M⁴ Show Affiliations
Source: Journal of Isfahan Medical School Published:2014

Abstract

Background: Anti-cyclic citrullinated peptide (CCP) antibodies are highly specific and predictive for rheumatoid arthritis (RA). Recently, existence of anti-CCP in several other inflammatory conditions from psoriatic arthritis to neurodegenerative disorder like Alzheimer's disease (AD) has been reported. We compared the level of anti-CCP titer between the patients with mild cognitive impairment (MCI) and Alzheimer's disease; then, we compared it between the patients with mild rheumatoid arthritis and Alzheimer's disease. Methods: In this cross-sectional study, 40 patients with rheumatoid arthritis, 29 patients with Alzheimer's disease, 30 patients with mild cognitive impairment and 30 healthy controls were enrolled. Anti-CCP titer was measured by solid phase enzyme immunoassay kit. Statistical analysis was performed using one-way analysis of variance and post-hoc Tukey tests. Findings: Level of anti-CCP titer (mean ± SD) was higher significantly in patients with Alzheimer's disease (13.6 ± 1.6) was higher than healthy subjects (4.2 ± 1.1) and patients with mild cognitive impairment (4.8 ± 1.3) (P = 0.0100 for both). Anti-CCP serum level in 32.1% of patients with Alzheimer's disease and 95.5% of patients with mild rheumatoid arthritis was higher than normal range. In addition, the antibody level was significantly higher in patients with rheumatoid arthritis (54.7 ± 4.8) compared to patients with Alzheimer's disease (P = 0.0001). Conclusion: We obviously observed differences in Anti-CCP titer between patients with Alzheimer's disease and those with mild rheumatoid arthritis. It was expected since anti-CCP has a high specificity for rheumatoid arthritis and become positive in early stages of disease with a high predictive value. However, we found that in early stages of cognitive impairment, we could not use this biomarker as a diagnostic test but during disease progression, a significant difference was observed between patients with mild cognitive impairment and those with Alzheimer's disease. It needs more studies to confirm the role of anti-CCP antibody production in patients with Alzheimer's disease.