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Anti-cyclic citrullinated peptides positivity rate in patients with familial Mediterranean fever
Mevlut Ceri1, Selman Unverdi, Mustafa Altay
1Department of Nephrology, Ankara Education and Research Hospital, Ankara, Turkey. tscer@yahoo.com
Objectives:
To investigate the prevalence and levels of anti-cyclic citrullinated peptide antibodies (anti-CCP) in patients with familial Mediterranean fever (FMF) with and without arthritis.
Methods:
Eighty-three patients with FMF and 43 healthy controls were included in the study. Thirty seven FMF patients had a history of arthritis, and 46 patients did not. Serum antibodies directed to the anti-CCP were assessed with a commercial enzyme-linked immunosorbent assay (ELISA) kit. Values <20U were considered negative, between 20 and 39U low, 40-99U moderate, and >100U high positive.
Results:
Positivity rate of anti-CCP in the whole FMF group (14.5%) was three-fold higher than the control group (4.7%). However, the difference failed to achieve a statistically significant level (p=0.09). Anti-CCP levels were 21±30.1 in patients with arthritis and 13.1±10.3 in the non arthritic group (p<0.05). Anti-CCP positivity rates were 10/37 (27%) in patients with arthritis and 2/46 (4.3%) in patients without arthritis (p<0.005). Five FMF patients with arthritis (13.5%) had moderate-high anti-CCP levels (>40U/ml). Anti-CCP levels were between 20-39U/ ml in 2FMF patients without arthritis and in 2 healthy controls. Anti-CCP positivity rate is higher in FMF patients with arthritis (27%) than healthy controls (4.7%) (p<0.005).
Conclusions:
Anti-CCP prevalence is higher in FMF patients with arthritis than without arthritis, and that a significant proportion of FMF patients with arthritis (13.5%) had moderate-high titers of anti-CCP. Therefore, anti-CCP antibodies may not be a reliable indicator to differentiate between FMF arthritis and rheumatoid arthritis.
Insights
Anti-cyclic citrullinated peptide antibodies (anti-CCP) are more prevalent in familial Mediterranean fever (FMF) patients with arthritis. Elevated anti-CCP levels in FMF arthritis patients suggest a potential overlap, but may not reliably distinguish FMF from rheumatoid arthritis.
Area of Science:
- Rheumatology
- Immunology
- Genetics
Background:
- Familial Mediterranean fever (FMF) is a genetic autoinflammatory disorder.
- Arthritis is a common manifestation of FMF, but its pathogenesis is not fully understood.
- Anti-cyclic citrullinated peptide antibodies (anti-CCP) are associated with rheumatoid arthritis.
Purpose of the Study:
- To determine the prevalence and levels of anti-CCP antibodies in FMF patients.
- To compare anti-CCP levels in FMF patients with and without arthritis.
- To explore the potential role of anti-CCP in differentiating FMF arthritis from rheumatoid arthritis.
Main Methods:
- Serum anti-CCP antibody levels were measured using ELISA in 83 FMF patients and 43 healthy controls.
- FMF patients were categorized into those with arthritis (n=37) and without arthritis (n=46).
- Anti-CCP levels were classified as negative (<20U), low (20-39U), moderate (40-99U), or high (>100U).
Main Results:
- Anti-CCP positivity was higher in the FMF group (14.5%) than in controls (4.7%), though not statistically significant (p=0.09).
- FMF patients with arthritis showed significantly higher anti-CCP levels (21±30.1 U) compared to non-arthritic FMF patients (13.1±10.3 U; p<0.05).
- Anti-CCP positivity was significantly higher in FMF patients with arthritis (27%) versus those without (4.3%; p<0.005) and controls (4.7%; p<0.005).
Conclusions:
- Anti-CCP antibody prevalence and levels are elevated in FMF patients with arthritis compared to those without.
- A notable proportion (13.5%) of FMF patients with arthritis exhibited moderate-to-high anti-CCP titers.
- Anti-CCP antibodies may not be a definitive marker for distinguishing FMF-associated arthritis from rheumatoid arthritis.
