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Antiperinuclear factor in psoriatic arthropathy
P G Calzavara-Pinton1, F Franceschini, C Manera
1Department of Dermatology, University of Brescia, Italy.
Background:
Antiperinuclear factor (APF) is an autoantibody directed against (pro)-filaggrin molecules.
Objective:
We evaluated whether APF determination is useful for the diagnosis of psoriatic arthritis (PA).
Methods:
We determined APF titers in sera from patients with PA (n = 76), psoriasis vulgaris (n = 38), noninflammatory rheumatic diseases (NIRDs, n = 119), rheumatoid arthritis (RA, n = 159) both with negative (n = 36) and positive (n = 123) rheumatoid factor (RF) tests, as well as from 204 healthy controls. We used an indirect immunofluorescence test on epithelial cells from human buccal mucosa as a substrate.
Results:
In patients with PA, 7.9% of the serum samples were APF-positive. The incidence was greater than in healthy controls (1.0%; P < .01), similar to those with uncomplicated psoriasis (2.6%; P = NS) and NIRDs (4.0%; P = NS), and lower than in RF-negative (52.7%; P < .001) and RF-positive (90.2%; P < .001) patients with RA. Three APF-positive patients with PA had symmetric joint involvement and 3 had pustulotic arthroosteitis.
Conclusion:
The APF test may be useful in differentiating PA from RA, and APF may be specific for two PA subgroups.
Insights
Antiperinuclear factor (APF) autoantibodies may help diagnose psoriatic arthritis (PA). While APF is not highly prevalent in PA patients, its presence can differentiate PA from rheumatoid arthritis (RA).
Area of Science:
- Immunology
- Rheumatology
- Dermatology
Background:
- Antiperinuclear factor (APF) is an autoantibody targeting (pro)-filaggrin.
- APF's diagnostic utility in psoriatic arthritis (PA) requires investigation.
Purpose of the Study:
- To assess the diagnostic value of APF determination in psoriatic arthritis (PA).
Main Methods:
- APF titers were measured in patients with PA, psoriasis vulgaris, noninflammatory rheumatic diseases (NIRDs), and rheumatoid arthritis (RA) (RF-positive and RF-negative).
- A cohort of healthy controls was included for comparison.
- Indirect immunofluorescence on human buccal epithelial cells served as the substrate.
Main Results:
- APF positivity was observed in 7.9% of PA patients.
- APF incidence in PA was significantly higher than in healthy controls (1.0%) but lower than in RA patients (52.7% RF-negative, 90.2% RF-positive).
- APF positivity was similar between PA, psoriasis vulgaris, and NIRDs.
Conclusions:
- The APF test shows potential for differentiating psoriatic arthritis (PA) from rheumatoid arthritis (RA).
- APF may be specific to certain subgroups within PA, such as those with symmetric joint involvement or pustulotic arthroosteitis.