P26 UK and Ireland paediatric primary Sjögren’s syndrome cohort study and repository (UK/Ireland PpSS cohort study and repository)
Authors: Foley Charlene , Obaidi Muthana Al , Ciurtin Coziana 
Published: September 2019

Poster presentation Tuesday 8 October

Background
Sjögren’s syndrome, a chronic multisystem autoimmune disease is characterised by inflammation of the exocrine glands, principally the salivary and lacrimal glands resulting in xerostomia and xerophthalmia. It can also present with more extensive exocrinopathy as well as extra-glandular, systemic features.
Defined as primary SS (pSS) when there is no association with other autoimmune disease, reported incidence and prevalence rates vary. Juvenile-onset pSS is believed to be rare; however it is likely that it is under-recognised and therefore under-diagnosed. To date there have been no studies reporting accurate incidence or prevalence of paediatric pSS (PpSS).
Diagnosing pSS can be challenging. Many of the cardinal symptoms are non-specific and no gold standard biomarker of disease exists. Between 1965–2002 eleven diagnostic criteria sets were developed, none of which have gained universal acceptance or been validated for use in a paediatric population. Until recently, the most widely used criteria were those developed by the American-European Consensus Group.
It remains well-recognised that international consensus on classification is important for standardisation, particularly in relation to research and monitoring treatment outcomes. With this in mind, the 2016 ACR/EULAR criteria were developed. However, there still remains a paucity of validated classification criteria for diagnosis of juvenile-onset pSS. Paediatric-focused criteria are required as features of pSS in children differ from those observed in adults. Children experience less dryness and more frequently experience systemic symptoms and parotid enlargement. Hence, simply applying adult criteria to a paediatric population may lead to mis- and/or under-diagnosis.
The overarching aim of this study is to identify epidemiological, clinical and laboratory characteristics of PpSS in a multi-centre cohort of patients. Using this data our goal is to develop universally accepted classification criteria validated for use in a paediatric population. Going forward, this would enable standardisation of PpSS classification allowing for robust studies into disease pathogenesis, management and prognosis.

Methods
Inclusion criterion for entry into the UK/Ireland PpSS cohort study and repository is diagnosis of pSS before 18 years. A data collection pack will be sent to authors willing to participate. Information collected will include demographic, clinical and laboratory/histological data at diagnosis and subsequent follow-up appointments. Biological samples including blood, tears, saliva, urine, and glandular and extra-glandular (e.g. renal) tissue will be collected prospectively if available. Outcome measures related to disease activity and damage, as well as patient reported outcomes will also be collected at set time-points.

Results
No results to report.

Conclusion
The UK/Ireland PpSS cohort study and repository will capture data on a significant cohort of children with pSS providing a powerful resource to help improve our understanding of this rare disease. Prospective data collection will allow a fuller analysis of poor prognostic features, impact of therapy, damage accrual and variable outcome of PpSS.

Conflicts of Interest
The authors declare no conflicts of interest.