FRI0489 ARE WE MISSING CASES OF HAEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS (HLH)? A FIVE YEAR RETROSPECTIVE SERVICE EVALUATION OF RECOGNITION AND RESPONSE TO FERRITIN &gt;10,000MG/L IN THE ADULT POPULATION OF A LARGE UK HOSPITAL TRUST
Authors: L. Kitchen, B. Jones, G. Dulay
Journal: Annals of the Rheumatic Diseases (2020)

Background: Haemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome presenting with fever, cytopaenias and multi organ failure, and carries a high mortality rate 1 . Primary HLH is genetic and presents in infancy. Secondary HLH (sHLH) presents in children or adults, and macrophage activation syndrome (MAS) 1 is sHLH in the context of rheumatological disease. Risk factors include immunosuppression, infection, malignancy and autoimmunity. The HScore can be used to calculate probability of HLH 2 . Gold standard diagnosis is bone marrow aspirate (BMA) 1 . In paediatrics, ferritin &gt;10,000μg/L is highly specific for HLH 3 , but less so in adults 4 . There is no validated treatment pathway for sHLH. Current recommendations are methylprednisolone and IVIG first line, and anakinra or etoposide if these are ineffective 1 . Objectives: This service evaluation assessed patients with a ferritin &gt;10,000μg/L in Portsmouth Hospitals NHS Trust (PHT) against diagnostic criteria and recommended treatment for sHLH, with the aim of sharing results to improve recognition and management. Methods: Serum ferritin results &gt;10,000μg/L from 1st March 2014 to 31st March 2019 were requested from PHT central laboratories. Paediatric and duplicate results were excluded. Electronic patient records were used to collect the parameters of the HScore 2 . HScore and probability of sHLH was calculated using a validated calculator 2,5 . Patient notes were requested for patients with missing data or probability of HLH &gt;1%. Results: Fifty four results were obtained from central laboratories, of which thirty eight were eligible for analysis. Mean age was 63.6 (range 19 to 96), 34.2% male. 47.4% died within one year of ferritin &gt;10,000μg/L. One patient was diagnosed with Adult Onset Still’s Disease. Of the remainder, 73% had risk factors for sHLH. Accurate assessment of sHLH incidence was not possible due to incomplete data, particularly triglycerides, fibrinogen, and BMA. AST is not routinely collected in PHT, therefore ALT was used for audit. Within these limits, fifteen patients had a probability &gt;1% of sHLH, and five had a probability &gt;50%. Only one patient had confirmed haemophagocytosis on BMA, and was treated for sHLH with oral steroids in addition to usual care. Conclusion: Although only one patient had confirmed sHLH on BMA, five patients had a &gt;50% probability of sHLH despite missing parameters for the HScore. It can be seen that potential cases of sHLH might easily be missed. Using a lower level ferritin cut-off for inclusion may have led to an even higher number of potential sHLH cases in our adult patient population. We suggest that sHLH should be considered as a plausible diagnosis in patients with raised ferritin, cytopaenias or organ failure. Local education work is planned to raise awareness of these learning points. References: [1]Carter S, Tattersall R, Ramanan A. Macrophage activation syndrome in adults: recent advances in pathophysiology, diagnosis and treatment. Rheumatology 2019; 55(1):5-17 [2]Fardet L, et al. Development and validation of the HScore, a score for the diagnosis of reactive hemophagocytic syndrome. Arthritis Rheum. 2014; 66(9):2613–20. [3]Allen CE, et al. Highly elevated ferritin levels and the diagnosis of hemophagocytic lymphohistiocytosis. Pediatr Blood Cancer. 2008;50(6):1227–35. [4]Schram AM, et al. Marked hyperferritinemia does not predict for HLH in the adult population. Blood. 2015; 125(10):1548-1552 [5]Fardet L. HScore. 2014. http://saintantoine.aphp.fr/score/ Disclosure of Interests: Lucy Kitchen: None declared, Bryony Jones: None declared, Gurdeep Dulay Grant/research support from: Educational grants to attend congress meetings/conferences from Roche, Chugai, UCB, Internis, Pfizer, Lilly, Sandoz, Consultant of: Honoraria for advisory board services from Roche, Chugai, Novartis, Speakers bureau: Speaker fees from Roche, Chugai, Novartis, Amgen, Lilly, Sandoz