P104 A review of patients referred to Rheumatology with haemophagocytic lymphohistiocytosis who were treated with anakinra successfully
Authors: Kurzeja Dominik , Perera James , Pillai Kavya , Amin Sanaah , Stratton Richard , Singh Animesh 
Published: April 2021

Abstract
Background/Aims
Haemophagocytic lymphohistiocytos (HLH) is a potentially life-threatening condition characterised by over-activation of the innate immune system. It can be classified into primary HLH, often inherited, or secondary which is triggered by non-genetic causes, such as chronic immunosuppression, malignancy or infection.Primary HLH is more frequently observed in infants, however, secondary HLH is more commonly observed in adults. Diagnosis is often delayed, most likely due to the rarity of the condition and is usually prompted by serological abnormalities, including hyperferritinaemia, organ and bone marrow dysfunction.Treatment options are limited; however, the Royal Free Hospital has observed a number of secondary HLH cases who were successfully treated with steroids and anakinra.
Methods
A retrospective search of clinic letters and patient records was undertaken using electronic care records. We also searched through pharmacy records of patients treated with anakinra at the Royal Free Hospital. Patients with a documented diagnosis of HLH prior to March 2020 who had been referred to Rheumatology were included. We excluded patients after March 2020 due to patients with COVID-19 having similar overlap of symptoms and biomarkers as those with HLH. We identified key demographic details, laboratory, pathology investigations,the course of hospital admission, primary diagnosis and follow-up data. The diagnosis was confirmed withan H-score and bone marrow biopsy where possible.
Results
We identified nine adult cases with adocumented diagnosis of HLH whohad been admitted to the Royal Free Hospitaland referred to Rheumatology. They had allbeen subsequently followed up in outpatientclinic.Ages of patients ranged from 19 to 58 with a male to female ratio of 2:1. The predominant underlying pathology was adultonsetStill’s disease(78%), with the remaining cases being secondary to HIV (22%). Bone marrow aspirate was performed in all patients and 78% of patients aspirated had bone marrowappearances in keeping with HLH.Ferritin levels varied from 532 micrograms/Lto 93309 micrograms/L with a median ferritin of 5045.5 micrograms/L.H-Scores were variable witha median score of 171.5 (96-238).All patients received steroids as part of their treatment. Anakinra (interleukin-1 receptor antagonist) was delivered intravenously(6/9) or subcutaneously (3/9).
Conclusion
We present data from nine cases of HLH treated with anakinra who survived their admission and have been subsequently followed up in clinic. We found that the majority of these patients had an underlying diagnosis of adult onset Still’s disease. Anakinra was used successfully as part of their treatment both intravenously as well as subcutaneously. Further work is needed comparing patients with good and poor outcomes to establish identifiable prognostic markers as well as effective treatment strategies.
Disclosure
D. Kurzeja: None. J. Perera: None. K. Pillai: None. S. Amin: None. R. Stratton: None. A. Singh: None.