Session Type: ACR Concurrent Abstract Session
Session Time: 2:30PM-4:00PM
Background/Purpose: To identify synovial tissue (ST) biomarkers differentially expressed in Psoriatic Arthritis (PsA) and seronegative Rheumatoid Arthritis (Abneg RA) and test their predictive value of therapeutic response.
Methods: 34 PsA patients [12 DMARDs naive and 22 no-responder to Methotrexate (MTX-IR)] with peripheral joint involvement and 55 Abneg RA (27 DMARDs naive and 28 MTX-IR) underwent US-guided ST biopsy and immunohistochemistry (IHC) for CD68+, CD3+, CD20+, CD21+, CD117+and CD138+cells. After study entry, each DMARD naive patient started MTX therapy and was fallowed in an outpatient setting for at least 6 months to define the achievement of Minimal Disease Activity (PsA) and DAS-remission (Abneg RA) status respectively. Each IR-MTX patient was treated according to EULAR recommendations.
Results: At study entry, there were no significant differences in terms of demographic and clinical characteristics of enrolled PsA and Abneg RA cohorts. IHC analysis revealed that naive PsA patients had lower IHC scores of lining and sublining CD20+than Abneg RA patients (p=0.002 and p=0.05 respectively), whereas no significant differences were found in terms of lining and sublining CD68+, CD21+and CD3+cells among the two cohorts. Moreover, regardless to the therapeutic scheme, PsA patients showed higher IHC score of lining and sublining CD117+cells (p<0.001 for both) compared to Abneg RA patients. Conversely, Abneg RA patients showed higher IHC score of lining and sublining CD138+cells, despite the therapeutic scheme (p=0.04 and p=0.01 for naive and MTX-IR respectively). Analysing the response rate to the therapeutic scheme, naive PsA patients reaching MDA status at 6 months follow-up, showed, at study entry, lower IHC score of sublining CD3+cells compared to PsA patients not reaching this outcome (p=0.03), conversely, naive Abneg RA patients reaching DAS-remission status at 6 months follow-up, showed, at study entry, lower IHC score of sublinig CD68+cells compared to Abneg RA patients not reaching this outcome (p<0.001).
Conclusion: CD117+and CD138+cells are differentially distributed among PsA and Abneg RA. Histological analysis of ST may help to solve the clinical overlap between the two diseases and provides prognostic data about the therapy success.
To cite this abstract in AMA style:Alivernini S, Bruno D, Fedele AL, Petricca L, Peluso G, Birra D, Tolusso B, Bui L, Federico F, Ferraccioli G, Gremese E. Synovitis in Psoriatic Arthritis and Seronegative Rheumatoid Arthritis: Differential Histological Features [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 10). https://acrabstracts.org/abstract/synovitis-in-psoriatic-arthritis-and-seronegative-rheumatoid-arthritis-differential-histological-features/. Accessed August 5, 2020.
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