P104 A review of patients referred to Rheumatology with haemophagocytic lymphohistiocytosis who were treated with anakinra successfully

Background/AimsHaemophagocytic lymphohistiocytos (HLH) is a potentially life-threatening condition characterised by over-activation of the innate immunesystem. It can be classified into primary HLH, often inherited, orsecondary which is triggered by non-genetic causes, such as chronicimmunosuppression, malignancy or infection.Primary HLH is morefrequently observed in infants, however, secondary HLH is morecommonly observed in adults. Diagnosis is often delayed, most likelydue to the rarity of the condition and is usually prompted by serologicalabnormalities, including hyperferritinaemia, organ and bone marrowdysfunction.Treatment options are limited;however, the Royal FreeHospital has observed a number of secondary HLH cases who weresuccessfully treated with steroids and anakinra.MethodsA retrospective search of clinic letters and patient records wasundertaken using electronic care records. We also searched throughpharmacy records of patients treated with anakinra at the Royal FreeHospital. Patients with a documented diagnosis of HLH prior to March2020 who had been referred to Rheumatology were included. Weexcluded patients after March 2020 due to patients with COVID-19having similar overlap of symptoms and biomarkers as those withHLH. We identified key demographic details, laboratory, pathologyinvestigations, the course of hospital admission, primary diagnosis andfollow-up data. The diagnosis was confirmed withan H-score and bonemarrow biopsy where possible.ResultsWe identified nine adult cases with adocumented diagnosis of HLHwhohad been admitted to the Royal Free Hospitaland referred toRheumatology. They had allbeen subsequently followed up inoutpatientclinic.Ages of patients ranged from 19 to 58 with a male tofemale ratio of 2:1. The predominant underlying pathology wasadultonsetStill's disease(78%), with the remaining cases beingsecondary to HIV (22%). Bone marrow aspirate was performed in allpatients and 78% of patients aspirated had bone marrowappearancesin keeping with HLH.Ferritin levels varied from 532 micrograms/Lto93309 micrograms/L with a median ferritin of 5045.5 micrograms/L.HScores were variable witha median score of 171.5 (96-238).All patientsreceived steroids as part of their treatment. Anakinra (interleukin-1receptor antagonist) was delivered intravenously(6/9) or subcutaneously (3/9).ConclusionWe present data from nine cases of HLH treated with anakinra whosurvived their admission and have been subsequently followed up inclinic. We found that the majority of these patients had an underlyingdiagnosis of adult onset Still's disease. Anakinra was used successfully as part of their treatment both intravenously as well assubcutaneously. Further work is needed comparing patients withgood and poor outcomes to establish identifiable prognostic markersas well as effective treatment strategies.