Avvedimento,

Cuccioloni, M

Funaro, A

Gabrielli, A

Grieco, A

Moroncini, G

Mozzicafreddo, M

Paolini, C

Salvucci, S

Tonnini, C

English

Institutional Research Information System University of Turin

64 Wednesday, 14 June 2017 Scientific Abstractsexpenditures were related to higher bDMARD uptake (Table), though not meetingstatistical significance (OR 1.91; 95% CI 0.93,3.92). Similar findings were foundwith country GDP (OR 1.72;95% CI 0.83,3.57).Conclusions: There remains important residual variation across countries inbDMARD uptake of patients with SpA followed in specialized SpA centers. Thisis despite adjustment of well-known factors for bDMARD use such as clinical andcountry-level socio-economic factors.Disclosure of Interest: None declaredDOI: 10.1136/annrheumdis-2017-eular.4480WEDNESDAY, 14 JUNE 2017Early diagnosis of systemic sclerosis and myositis:biomarkers and diagnostic toolOP0031 DEVELOPMENT OF A NOVEL EPITOPE-BASED DIAGNOSTICASSAY FOR SYSTEMIC SCLEROSISG. Moroncini 1, M. Mozzicafreddo 2, M. Cuccioloni 2, A. Grieco 1, C. Paolini 1,C. Tonnini 1, S. Salvucci 1, E. Avvedimento 3, A. Funaro 4, A. Gabrielli 1.1Department of Molecular and Clinical Sciences, Università Politecnica Marche,Ancona; 2School of Biosciences and Veterinary Medicine, University ofCamerino, Camerino; 3Department of Molecular Medicine, Università Federico II,Napoli; 4Department of Medical Sciences, University of Torino, Torino, ItalyBackground: We described the conformational PDGFRα epitope of VHPAM–Vκ16F4 agonistic autoantibody1, cloned from memory B cells of a SSc patient,that can induce fibrosis in vivo2. We showed that peptides composing this epitopemay be specifically recognized by serum IgG of patients with systemic sclerosis(SSc), but not of controls.Objectives: i. To identify the immunodominant peptide within the discontinuousPDGFRα epitope of VHPAM–Vκ16F4; ii. to identify other immunodominantepitopes recognized by agonistic autoantibodies; iii. to use these immunodominantpeptides to develop an epitope-based assay for diagnosis of SSc and classificationof SSc clinical subtypes.Methods: i.The large PDGFRα peptide library used for epitope mapping ofmonoclonal anti-PDGFRα antibodies1 was screened with 25 SSc (12 limited,13 diffuse) and 25 healthy control (HC) serum samples. ii. A smaller PDGFRαpeptide library containing only the top 20 conformational binders plus 20 linearand 20 conformational controls was synthesized. 60 conformational and linearpeptides of a cognate protein forming a molecular complex with PDGFRα wereincluded in the array. 20 scrambled peptides were added as negative controls.This library was screened with the same 50 serum samples. iii. A third librarywas synthesized, retaining the top cognate protein peptide binders, and 15chimeric PDGFRα/cognate protein peptides, chosen among the best binders,with some nonbinding controls. This library was tested as before. Libraries weresynthesized by Pepscan Presto, Netherlands. Statistical analysis was performedby Wilcoxon-Mann-Whitney test. Correlations between serological results andclinical status were made.Results: i. An immunodominant peptide discriminating SSc from HC serumsamples was identified in the first library. ii. This was confirmed by the secondlibrary, which highlighted also one immunodominant epitope from the cognateprotein. Statistical analysis identified two cohorts of SSc samples (reactive vsnonreactive, the latter undistinguishable from HC) each composed by limited anddiffuse SSc subtypes. iii. The third peptide library identified the chimeric peptiderecognized exclusively by the reactive SSc serum samples, which were takenfrom patients with active, progressive disease regardless of limited vs diffuseclassification, whereas the nonreactive SSc samples were taken from subjectswith less active, non progressive disease.Conclusions: We developed a conformational epitope-based assay detectingSSc-specific, agonistic, serum autoantibodies. The preliminary results suggestthat this novel array may identify SSc patients with active disease, regardlessof the canonical classification criteria. We propose this assay for prospectivescreening of large cohorts of patients affected by, or suspected for, SSc, tovalidate it as a tool for disease activity assessment and/or early diagnosis.References:[1] Moroncini G et al. Epitope specificity determines pathogenicity and de-tectability of anti-PDGFRα autoantibodies in systemic sclerosis. Arthritis andRheumatology. 2015; 67(7):1891–1903.[2] Luchetti MM et al. Induction of Scleroderma Fibrosis in Skin-Humanized Miceby Administration of Anti-Platelet-Derived Growth Factor Receptor AgonisticAutoantibodies. Arthritis & Rheumatology. 2016; 68(9):2263–73.Disclosure of Interest: None declaredDOI: 10.1136/annrheumdis-2017-eular.6009OP0032 IS IMMUNOHISTOCHEMISTRY USEFUL TO PREDICTRESPONSE TO TREATMENT IN NECROTIZING MYOPATHIES?S. Fernandes 1, B. Lopez 2, P. Gordon 2, S. Al-Sarraj 3. 1Rheumatology, InstitutoPortuguês de Reumatologia, Lisbon, Portugal; 2Rheumatology; 3ClinicalNeuropathology, King’s College Hospital, London, United KingdomBackground:Muscle biopsy is the gold standard for the diagnosis of inflammatorymyopathies, but the role of immunohistochemistry in Necrotizing Myopathies (NM)has not been fully characterized yet.Objectives: To determine if MHC-I expression and pattern of C5b-9 deposition incapillaries correlate with clinical phenotype and response to treatment in NM.Methods: The Neuropathology Departmental database was searched to identifypatients with a histological diagnosis of NM and follow up data for at least 6months (30 patients). Electronic patient records were reviewed retrospectively torecord demographics, autoantibodies, treatment, proximal muscle power at 3, 6and 12 months by Manual Muscle Testing (MMT) (2), levels of CK and flares.Patients were classified as responders when there was improvement of MMT≥20% and non-responders when MMT improvement was <20% (3). All biopsieswere reviewed blindly by an experienced neuropathologist. MHC-I expressionwas classified as positive only if over expressed in all fibers. The patterns ofC5b-9 deposition in endomysial capillaries were classified as specific (solid),non-specific (granular) or negative.Results: MHC-I positive group (n=16/30) had a higher proportion of responders(62,5% vs 7,7%, p=0.002), higher number of patients with total recovery of musclepower (66,7 vs. 15,4%) and were more commonly positive for autoantibodies(75% vs. 35.7%, p=0.030) when compared to the MHC-I negative group (n=14).17 patients were positive for auto-antibodies of which 9 were myositis specificantibodies [SRP (n=6), HMG-CoA reductase (n=1), Jo-1 (n=1), P155/140 (n=1)]and 4 were myositis associated antibodies [Ro-52 (n=2), Ku (n=1), Pm/Scl (n=1)].13/30 patients had C5b-9 deposition, with a specific pattern in 5 and non-specificin 8. The specific pattern group had a greater reduction of CK after 6 monthscompared to non-specific and negative respectively (98% vs. 77% vs. 56.8%,p=0.006), greater reduction in CK after 12 months (96.6% vs. 68.9% vs. 59.6%,p=0.024) and higher rates of responders (80% vs. 60% vs. 18,8%, p=0.001). Sixpatients were on immunosuppressants (azathioprine/hydroxychloroquine, n=2),steroids (n=3) or both (n=1) for a minimum of 4 weeks when the biopsy wasperformed. Differences in age, gender, clinical features or treatment were notfound to be statistically significant.Conclusions: Upregulation of MHC I and solid staining pattern of C5b-9 in thecapillaries of NM patients appears to be associated with a better outcome.References:[1] Cong L, Pu CQ, Shi Q, Wang Q, Lu X, Complement membrane attack complexis related with immune-mediated necrotizing myopathy, Int J Clin Exp Pathol2014;7(7):4143–41499.[2] Rider LG, Koziol D, Giannini EH, Jain MS, Smith MR, Whitney-Mahoney K,Feldman BM, Wright SJ, Lindsley CB, Pachman LM, Villalba ML, Lovell DJ,Bowyer SL, Plotz PH, Miller FW, Hicks JE.[3] Vencovsky J, New ACR/EULAR Criteria for Myositis, Ann Rheum Dis2015;74:42–43.Disclosure of Interest: None declaredDOI: 10.1136/annrheumdis-2017-eular.6814OP0033 SPECT- AND PET/CT IMAGING IN NEWLY ONSET IDIOPATHICINFLAMMATORY MYOPATHYJ. Simonsen 1, S. Hvidsten 1, P.F. Høilund-Carlsen 1, K.F. Thøgersen 1,2,O. Gerke 1, S. Jacobsen 3, L.P. Diederichsen 4,5. 1Nuclear Medicine, OdenseUniversity Hospital, Odense C; 2Aalborg University Hospital, Aalborg;3Copenhagen Lupus and Vasculitis Clinic, Center for Rheumatology and SpineDiseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen;4Reumatology, Odense University Hospital, Odense C; 5Clinical Research,University of Southern Denmark, Odense, DenmarkBackground: Diagnosis of idiopathic inflammatory myopathies (IIMs) is challeng-ing and so far no pathognomonic signs exist by imaging. Few radionuclide imagingtechniques have been tested for this purpose, mainly 99mTc-pyrophosphate planarimaging and 18F-fluorodeoxyglucose positron emission tomography/computedtomography (18F-FDG-PET/CT). However, 99mTc-PYP uptake has been assessedvisually and at best graded semi-quantitatively.Objectives: We aimed for quantitative 99mTc-pyrophosphate single photonemission computed tomography/computed tomography (99mTc-PYP-SPECT/CT)as well as 18F-FDG-PET/CT imaging in a group of newly onset IIM patients.Methods: Thirteen patients (mean age 62 years) with newly diagnosed, untreatedIIM underwent 99mTc-PYP SPECT/CT of the thorax, pelvis, and thighs. Seven ofthe patients also had a whole-body 18F-FDG PET/CT scan. Forty-nine healthycontrols (mean age 59 years) underwent 99mTc-PYP SPECT/CT and 26 healthycontrols (mean age 57 years) had a 18F-FDG PET/CT scan done. Volumesof interest (VOIs) covering the right biceps, triceps, and quadriceps muscleswere drawn manually on each series. Registered 99mTc-PYP counts, respectivelystandardized uptake values (SUVs) of 18F-FDG were obtained from all VOIs.Registered counts were decay- and attenuation-corrected and adjusted for bodyweight and administered dose of 99mTc-PYP, yielding a parameter similar to theSUV [g mL-1].

Development of a novel epitope-based diagnostic assay for systemic sclerosis

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Development of a novel epitope-based diagnostic assay for systemic sclerosis

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