s Committee: Chair: Kentaro Ikeda, DDS, MPH Co-Chair: Bhavik Desai, DMD, PhD #11 – 3:00-3:10pm The Parotid Gland in Primary Sjögren’s Syndrome: Association of Ultrasound, Histopathology and Saliva Production in the Diagnostic Work-up *Konstantina Delli, Esther Mossel, Erlin Haacke, Bert van der Vegt, Suzanne Arends, Uzma Nakshbandi, Jolien F van Nimwegen, Alja J Stel, Fred KL Spijkervet, Frans GM Kroese, Arjan Vissink, Hendrika Bootsma University Medical Center Groningen, Netherlands Objectives: The parotid glands are commonly involved in primary Sjögren’s syndrome (pSS). The aim of this study was to assess the diagnostic accuracy of ultrasound of the parotid glands (PSGUS) compared with the parotid histopathology and parotid saliva production. Methods: We included consecutive patients suspected with pSS. All patients underwent a full diagnostic work-up according to ACR-EULAR criteria, including PSGUS, parotid gland biopsy and collection of stimulated parotid saliva. For PSGUS, the average score of hypoechogenic areas in both parotid glands was applied (range 0-3). On H&E stained sections from parotid gland biopsies, focus score, presence of lymphoepithelial lesions (LELs) and germinal centers (GCs) were assessed. The area of lymphocytic infiltrate was calculated digitally on CD45 stained sections. The relative increase of IgG expressing plasma cells (≥30%) was evaluated on sections stained for IgA and IgG. PSGUS score was associated with focus score, percentage of infiltrate and saliva flow and compared with plasma cell shift, LELs and GCs by calculating the percentage of absolute agreement, sensitivity and specificity. Results: In total, of the 111 included patients, 53 fulfilled the ACR-EULAR classification criteria for pSS. PSGUS score showed moderate correlation with focus score (ρ=0.494, p<0.001) and percentage of lymphocytic infiltrate (ρ=0.575, p<0.001). There was a moderate to good absolute agreement between PSGUS and focus score (78.5%), plasma cell shift (79.8%), LELs (81.4%) and GCs (82.7%). ‘Presence of hypoechogenic areas’ was not very sensitive to predict focus score (69.2%), plasma cell shift (45.8%), LELs (61.5%) or GCs (34.6%). Interestingly, almost all patients with <25% presence of hypoechogenic areas in glandular parenchyma were also negative for GCs (98.7%). A substantial amount of these patients did not have a positive focus score (81.4%), plasma cell shift (90.7%) or LELs (87.8%). There was a fair reversed correlation between PSGUS and stimulated parotid saliva flow (ρ=-0.259, p=0.07). Conclusions: This is the first study comparing the diagnostic accuracy of PSGUS with histopathology and salivary secretion in detail. PSGUS and histopathology are stronger associated than PSGUS and parotid secretion. Specificity of PSGUS increases when results are compared to plasma cell shift, LELs and GCs, instead of focus score. #12 – 3:10-3:20pm Novel Anti-CD40 Monoclonal Antibody CFZ533 in Patients with Primary Sjogren Syndrome: A Phase IIa Double-Blind, Placebo–Controlled Randomized Trial *Arwa Farag, Athena Papas, Benjamin Fisher, Margit Zeher, Wan-Fai Ng, Michele Bombardieri, Maximilian Posch, Thomas Daikeler, Bettina Bannert, Alan Kivitz, Steven Carsons, David Isenberg, Francesca Barone, Simon Bowman, Pascal Espie, Grazyna Wieczorek, Pierre Moulin, David Floch, Cyrielle Dupuy, Xiaohui Ren, Petra Faerber, Andrew Wright, Hans Ulrich Hockey, Michael Rotte, James Rush, Peter Gergely Tufts University School of Dental Medicine, USA