Document Type : Original Article (s)
Authors
1
Assistant Professor, Department of Pharmacology, School of Medical Sciences, Islamic Azad University, Najafabad Branch, Isfahan, Iran
2
Associate Professor, Department of Biostatistics and Epidemiology, School of Public Health, Isfahan University of Medical Sciences, Isfahan, Iran
3
Assistant Professor, Isfahan Neurosciences Research Center AND Department of Neurology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
4
Assistant Professor, Department of Rheumatology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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.
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