Somatostatin receptor scintigraphy in patients with rheumatoid arthritis and secondary Sjögren's syndrome treated with Infliximab: a pilot study.
BACKGROUND
Human T lymphocytes infiltrating tissues in autoimmune diseases are known to express somatostatin receptors amongst other activation markers. In this study, we evaluated whether somatostatin receptor scintigraphy (SRS) using a radiolabelled somatostatin analogue ((99m)Tc-EDDA/tricine-HYNIC-tyr(3)-octreotide ((99m)Tc-EDDA/HYNIC-TOC)) is able to detect the presence of immune-mediated processes in patients with rheumatoid arthritis and secondary Sjögren's syndrome. We also aimed to evaluate whether positivity to SRS was predictive of therapeutic response and if SRS could be used for monitoring the efficacy of immunomodulatory treatment.


METHODS
Eighteen patients with rheumatoid arthritis and secondary Sjögren's syndrome not responding to conventional treatment were recruited for treatment with infliximab, a monoclonal antibody against TNF-α. All patients had complete blood cell count, renal and liver function tests, measurements of ESR, CRP, ANA, ENA, and anti-dsDNA antibodies, functional salivary gland scintigraphy, labial biopsy, and ophthalmologic assessment with Schirmer's test and tear film break-up time (BUT). Diagnosis was made according to the revised criteria of the American-European Consensus Group. All patients underwent SRS at baseline and after 3-6 months of therapy with infliximab. Eleven out of 18 had repeat SRS images. Images of the salivary glands and major joints were acquired 3 h after injection of 370 MBq of (99m)Tc-EDDA/HYNIC-TOC. Image analysis was performed semi-quantitatively.


RESULTS
All patients showed uptake of (99m)Tc-EDDA/HYNIC-TOC in the joints. Salivary glands also showed variable radiopharmaceutical uptake in 12 out of 18 patients, but all patients showed presence of lymphocytic infiltration at labial salivary gland biopsy. All patients, who repeated the study after treatment, showed significant reduction of somatostatin uptake in the joints but not in the salivary glands.


CONCLUSIONS
SRS using (99m)Tc-EDDA/HYNIC-TOC may be a useful imaging tool to assess disease activity and extent in patients with rheumatoid arthritis and may help to detect secondary Sjögren's syndrome. It may also aid therapy decision-making with anti-TNFα antibodies in the joints but not in salivary glands.
Nuclear Medicine Unit, Clinica Reina Sofia, Bogotà, Colombia.|Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
L K
LK
Anzola-Fuentes
Nuclear Medicine Unit, Department of Diagnostic Imaging, Regina Apostolorum Hospital, Albano, Rome, Italy.
M
M
Chianelli
Nuclear Medicine Unit, Faculty of Medicine and Psychology, "Sapienza" University, Rome, Italy. filippo.galli@uniroma1.it.|Nuclear Medicine Unit, Department of Medical-Surgical Sciences and of Translational Medicine, Sapienza University of Rome, Rome, Italy. filippo.galli@uniroma1.it.
F
F
Galli
Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
A W J M
AW
Glaudemans
Rheumatology Unit, Department of Internal Medicine, Regina Apostolorum Hospital, Albano, Rome, Italy.
L
L
Martin Martin
Rheumatology Unit, Department of Internal Medicine, Regina Apostolorum Hospital, Albano, Rome, Italy.
V
V
Todino
Division of Internal Medicine, Ospedale Fatebene Fratelli S. Pietro, Rome, Italy.
A
A
Migliore
Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.|Nuclear Medicine Unit, Faculty of Medicine and Psychology, "Sapienza" University, Rome, Italy.
A
A
Signore
99mTc-EDDA/HYNIC-TOC; Inflammation imaging; Infliximab; Rheumatoid arthritis; Sjögren; Somatostatin receptor scintigraphy