Value of Somatostatin Receptor Scintigraphy with 99mTc-HYNIC-TOC in Patients with Primary Sjögren Syndrome.

Luz Kelly Anzola,Stefano Valabrega,Rudi A. Dierckx,Josè Nelson Rivera,Alberto Signore,Chiara Lauri,Andor W. J. M. Glaudemans,Filippo Galli,Sergio Moreno Lopez

doi:10.3390/jcm8060763

Abstract

Objectives: Primary Sjögren syndrome (SS) is diagnosed based on the American European Consensus Group (AECG) criteria, but lacks specificity, not only in the involvement of salivary glands, but also in extra-glandular involvement. Whole-body somatostatin receptor scintigraphy with 99mTc-HYNIC-TOC scintigraphy could overcome these limitations. The aims of this study were to evaluate salivary gland uptake of 99mTc-HYNIC-TOC in untreated patients with de-novo diagnosis of SS as compared to control subjects and as compared to conventional sialoscintigraphy with 99mTcO4−. We also aimed to evaluate the involvement of joints. Methods: 99mTc-HYNIC-TOC was used with SS patients and uptake in joints and salivary glands was analyzed semi-quantitatively. Patients also underwent 99mTcO4 sialoscintigraphy. The control group that we analyzed consisted of 30 patients with neuroendocrine tumors. Results: Fifty-two females and 10 males fully met the AECG criteria for SS, and were included. A target background ratio (TBR) >1.18 in submandibular glands correctly classified 93% of the patients with SS in comparison to 27% for 99mTcO4 sialoscintigraphy. The area under the curve (ROC) analysis for TBR in submandibular glands was 0.95. In joints there was a huge variety in uptake. The median TBR was significantly higher in salivary glands in patients with SS compared to controls. Conclusions: 99mTc-HYNIC-TOC scintigraphy identified active inflammatory processes not only in the salivary glands, but, unexpectedly, also in many joints in patients with primary SS, contrary to popular belief. This technique provides an objective parameter to evaluate the inflammation burden in salivary glands and joints and could be used to evaluate response to treatment.

Highlights

Sjögren syndrome (SS) is a systemic autoimmune disease that primarily affects the salivary and lacrimal glands
Regarding the negative control group, we evaluated the uptake of salivary glands uptake and joints uptake of 99mTc-HYNIC-TOC in 30 patients in whom the scan was performed for staging of NET
It is remarkable how much the frequency of the symptoms and the positive laboratory tests results that belong to American European Consensus Group (AECG) criteria vary

Summary

Introduction

Sjögren syndrome (SS) is a systemic autoimmune disease that primarily affects the salivary and lacrimal glands It usually causes a persistent dryness of the mouth and eyes due to lymphocytic infiltration and impairment of the exocrine glands [1,2]. The ACR-EULAR initiative has decided to reunite the criteria to make clinical studies and therapeutic trials comparable [9] In this new approach, sialoscintigraphy is not included as diagnostic criterion. Diagnosing secondary SS has not yet been addressed by the AECG, in practice it is usually required to fulfill the criteria for primary SS and to fulfill the American College of Rheumatology (ACR) criteria for an established connective tissue disease such as rheumatoid arthritis (RA), SLE, dermatomyositis, myositis, or biliary cirrhosis [11]. Besides overexpression in several autoimmune and granulomatous diseases, such as RA, SLE, Schönlein–Henoch, autoimmune uveitis, ulcerative colitis, sarcoidosis, tuberculosis, and Crohn’s disease, SSTR overexpression is well known in patients with SS [15,16]

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