P23 Establishment of a cross-specialty collaboration and national registry to enable research and improve management of haemophagocytic lymphohistiocytosis/macrophage activation syndrome
Authors: Sen Ethan S. , Collin Matthew , Ramanan Athimalaipet V. , Tattersall Rachel S. , Manson Jessica J. 
Published: October 2019

Poster presentation Tuesday 8 October

Background
Haemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) is a hyperinflammatory syndrome which can complicate sepsis, malignancy or autoimmune/autoinflammatory disease, potentially leading to critical illness and death at all ages. A previous service evaluation of children with ferritin > 10,000 μg/L, which is highly specific for HLH/MAS, reported mortality of 33% and in 44% there was no documented evidence that HLH had been considered by clinicians. The condition may present to generalists, specialists and intensivists and prompt recognition and treatment can be life-saving. A consensus for the management of HLH in older children and adults has not been defined. The aim of this ongoing project is to identify current practice and improve the evidence-base for diagnosis and treatment of HLH.

Methods
A national cross-specialty group was established in June 2018 including paediatric and adult specialists in rheumatology, haematology, oncology, immunology, infectious diseases, virology, nephrology and intensive care. Clinicians, scientists, pharmacists and data management experts have been incorporated. The group, which numbers over 50 professionals, has met on three occasions to set clinical and research priorities and is supported by Histiocytosis UK, a charity representing patients with HLH.

Results
The group agreed these priorities: To complete a retrospective service evaluation of adult patients with ferritin > 10,000 μg/L identified over a 3-year period using a standardised proforma established in the previous paediatric cohort [provisionally, this has identified over 200 adults with a mortality rate of 39%]To provide education to clinicians across the UK to improve recognition of HLH [in progress]To develop guidance for investigation of suspected HLH [in progress]To link local multi-specialty teams experienced in managing HLH to create a national network [in progress]To conduct a retrospective, observational study of the use and outcomes of anakinra treatment in HLHTo establish a national registry for HLH as part of the UK Histiocytosis Registry (UKHR) using the REDCap online portal for data collection.
Patients with definite and probable HLH, including those with MAS secondary to rheumatological conditions, will be eligible for recruitment.
Baseline demographic and clinical data, investigations which contribute to the HLH 2004 criteria and H score, and underlying diagnoses will constitute a minimal dataset. Treatments, and responses, and long-term follow-up data will be recorded. In addition to data collection, with the appropriate consents, biological samples will be available for genetic and histopathological analysis and cellular samples for in vitro studies.

Conclusion
HLH/MAS is an under-recognised condition with high mortality. A national cross-specialty, all-age collaboration has established priorities to improve clinical care and advance research. Development of a registry, with collection of biological samples, will facilitate investigation of disease pathogenesis and help to stratify patients with a view to future clinical trials.

Conflicts of Interest
The authors declare no conflicts of interest.