Background/Purpose
Previously we described antibodies against ferritin heavy chain peptide (anti-FHCP) in sera of patients with giant cell arteritis (GCA) and/or polymyalgia rheumatic (PMR) before glucocorticoid treatment was initiated. In that study, it remained unclear however, whether the PMR patients may have suffered from additional undiagnosed GCA. Therefore, we now measured antibodies against FHCP in PMR patients in whom GCA had been excluded by FDG-PET scan.
Methods
Sera of 63 patients were studied that presented initially with symptoms of PMR. A PET-CT had been performed in all patients and revealed large vessel vasculitis in 27 of these patients (GCA/PMR), whereas 36 had no signs of vasculitis (PMR). In a single-blinded study, we measured anti-FHCP in these patients and in a control group of patients with rheumatic diseases (RD, n=26), malignant diseases (MD, n=15) and infectious febrile diseases (IFD, n=22).
In the ELISA 3 peptides of the ferritin heavy chain were used as antigens: A19-45 (AAINRQINLELYASYVYLSMSYYFDRF), A79-104 (GRIFQDIKKPCDDWESGLNAMECA) and A105-143 (LHEKNVNQSLELHKLATDKNDPHLCFIETHYLNEQVK).
Results
The frequency of antibodies against A19-45 were 38/63 (60%) in all PMR patients and 14/63 (22%) in controls (p<0.0001), of antibodies against A79-104 30/63 (48%) in all PMR patients and 9/63 (14%) in controls (p=0.0001) and of antibodies against A105-143 38/63 (60%) in PMR and 12/63 (19%) in controls (p<0.0001). There were no differences within the controls considering all antigens.
Comparing the patients with and without vascular involvement in PET-CT, the frequencies of antibodies against A19-45 (18/27 (67%) and 20/36 (56%), (p=0.53)), against A79-104 (14/27 (52%) and 16/36 (44%) (p=0.74)) and against A105-143 (19/27 (70%) and 19/36 (53%) (p=0.25)) were not different.
Conclusion
This single-blinded study confirms the frequency of anti-FHCP in a different cohort. Anti-FHCP are associated with both GCA/PMR and PMR only.
Disclosure:
N. T. Baerlecken,
None;
T. Witte,
None;
M. A. Cimmino,
None;
D. Camellino,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/pet-ct-imaging-and-association-of-ferritin-autoantibodies-in-polymyalgia-rheumatica/