A PH I Pilot Imaging Study to Evaluate Molecular Imaging Methods in HVs and pSS Pts

Inclusion Criteria

• GROUP A: Healthy Volunteers Subjects for both PET/CT and MRI: Aged >=40 years inclusive at the time of signing the informed consent.

Subjects for MRI, without PET/CT: Aged >=30 years inclusive at the time of signing the informed consent Healthy as defined by the investigator, or medically qualified designee, based on a medical evaluation including medical history, physical examination, and laboratory tests.

• Group B: Primary Sjögren's Syndrome Patients Age >=30 years, at the time of signing the informed consent. Diagnosis of pSS according to the American-European Consensus Group criteria Baseline unstimulated salivary flow >0.0 mL/min or evidence of glandular reserve function (stimulated baseline salivary flow >0.05 mL/min).

Systemically active disease, ESSDAI >=5 points

• All Subjects Body weight >=50 kilogram (kg) and body mass index within the range 18.5 to 35 kg/m^2 (inclusive)

Male or Female, where one of the following conditions apply:

A female subject is eligible to participate if she is not pregnant (as confirmed by a negative serum human chorionic gonadotrophin test) at screening, and a negative urine pregnancy test 4-7 days prior to Visit 1, on the day of Visit 1 (on each day of scanning), on Visit 2, is not lactating, and at least one of the following conditions applies: non-reproductive potential or reproductive potential and agrees to use contraceptive methods listed in the protocol from 28 days prior to Visit 1 until follow up.

• Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form.

Exclusion Criteria

• Diagnosis of secondary Sjögren's Syndrome.
• Diagnosis of another systemic autoimmune disease, apart from pSS, including but not limited to, systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis or systemic vasculitis. For Group B subjects, autoimmune conditions associated with pSS (for example autoimmune thyroiditis, primary biliary cirrhosis or coeliac disease), are not included in this exclusion, but should be described in the medical history taken baseline. If in doubt please consult the medical monitor.
• Subjects with active life-threatening or organ-threatening effects of pSS meaning that they may not be able to complete the study visits according to the protocol (as determine by the investigator) (Group B).
• History of coagulation or bleeding disorders which would increase the risk of minor salivary gland biopsy (for example, but not limited to, Hemophilia A or B, Von Willibrand's disease, platelet function disorders; Group B).
• History of malignancy within 5 years of screening that, in the view of the investigator, in consultation with the medical monitor if required, could confound the results of the 18F-FDG PET/CT scan (including lymphoma associated with pSS). This does not include cervical carcinoma in situ or non-melanoma skin malignancy that has been treated with curative surgical treatment.
• History of unresolved acute or chronic infection that, in the view of the investigator in consultation with the medial monitor, if required, could confound the results of the 18F-FDG PET/CT.
• Subject with diabetes mellitus requiring insulin therapy
• Contraindications to MRI scanning (as assessed by MRI safety questionnaire).
• History of, or suffers from, claustrophobia or feel that they will be unable to lie still in the PET or MRI scanner for a period of up to 1 to 2 hours.
• Where participation in the study would result in donation of blood or blood products in excess of 500mL within a 56 day period.
• Previous inclusion in a research protocol involving nuclear medicine, PET or radiological investigations, or as a result of occupational exposure with a significant radiation burden (a significant radiation burden being defined as 10mSv in addition to natural background radiation, in the previous 3 years including the dose from this study). A clinical procedure wher