AB0439 Contribution of anti-ferritin antibodies to the diagnosis of giant cell arteritis. (23rd January 2014)

• Record Type: Journal Article
• Authors: Regent, A.; Ly, K. H.; Blet, A.; Agard, C.; Puéchal, X.; Tamas, N.; Le-Jeunne, C.; Vidal, E.; Guillevin, L.; Mouthon, L.
• Is Part Of: Annals of the rheumatic diseases. Volume 72:Supplement 3(2013)
• Page Start: A922
• Page End: A923
• Publication Date: 2014-01-23
• Subjects: Rheumatism -- Periodicals; 616.723005
• DOI: 10.1136/annrheumdis-2013-eular.2761
• Languages: English
• ISSNs: 0003-4967

Abstract

Abstract : Background: The diagnosis of giant cell arteritis (GCA) can only be ascertained by performing temporal artery biopsy (TAB), and there is no validated biomarker valuable for the diagnosis and/or characterization of the prognosis in this condition. Recently, Baerlecken et al. reported on the detection of antibodies directed at the human ferritin heavy chain (FTH1)in 92% of patients with GCA vs 1% of healthy controls. Objectives: We decided to evaluate the diagnostic value of anti-ferritin antibodies in patients undergoing TAB for a suspicion of GCA. Methods: We included 122 consecutive patients suspected of GCA. Blood sampling was performed at the time of TAB. Among these, 40 had biopsy proven GCA (TAB+ GCA), 29 had biopsy-negative GCA (TAB- GCA), 6 had polymyalgia rheumatica (PMR) and another diagnosis that GCA (GCA controls) and/or PMR was retained in 47 patients. Sera from 40 healthy individuals served as negative controls. We investigated for the presence of IgG directed against 19-45 FTH1 amino-acids by using an ELISA test. Correlations between FTH1 antibodies and clinical manifestations were investigated using non parametrical tests. Results: Anti-FTH1 antibodies were identified in 72.5%, 41.3.9%, 31.9% and 2.5% of patients with TAB+ GCA, TAB- GCA, GCA controls and healthy individuals, respectively, with a threshold at the mean of healthy controls + 2 standard deviations (SD). With a threshold at the mean of healthy controls + 3 SD, anti-FTH1 antibodies were identified in 60%, 34.5%, 21.2% and 0% of the patients with TAB+ GCA, TAB- GCA, GCA controls and healthy individuals, respectively. By grouping TAB+ GCA, TAB- GCA patients with a threshold at 2 SD, the positive and negative predictive value were of 71.9 and 56.9%, respectively. Positive and negative likely ratio were at 1.96 and 0.58, respectively. In addition, in our population, anti-FTH1 antibody titer as measured by OD level correlated significantly with CRP and no correlation was found with aortic and/or visual impairment. Conclusions: We therefore confirm the presence of anti-FTH1 in 72.5% of patients with histologically proven GCA. However, the detection of anti-FTH1 is not contributory to the diagnosis of GCA in a cohort of patients with suspected ACG. The ability to identify a specific sub-group of patients by ELISA should be evaluated by testing a larger cohort of patients with GCA. References: Baerlecken et al. Ann Rheum Dis. 2012 Jun;71(6):943-7. Disclosure of Interest: None Declared