Ab1401 Haemophagocytic Syndrome in Adults: Description of a Single-Center Experience in Portugal

Background: Haemophagocytic lymphohistiocytosis (HLH) is associated with high mortality, and its early recognition and treatment might reduce mortality. The role of coordinated multidisciplinary teams is to further accelerate the approach in stratification, treatment and pursuit of major triggers and underlying predisposing diseases, as timely and adequate treatment is crucial to the prognosis. Objectives: To describe a single center experience in both retrospective and prospective cohorts, before and after the establishment of a multidisciplinary HLH team, respectively. Methods: Review of demographic, clinical (HLH diagnosis, organ/system dysfunction stratification, triggers and underlying predisposing diseases) and laboratory features, directed treatment and outcome of a retrospective cohort (1-1-2007 to 31-12-2018) and a prospective cohort (1-1-2019 to 31-12-2023). Results: Fifty-seven HLH episodes in 51 patients, 22 (39%) episodes in the retrospective cohort and 35 (61%) prospectively collected. Thirty-three (65%) patients were male. Mean age at HLH episode diagnosis was 53 years (range 17-88). Mean duration from symptoms onset to HLH diagnosis was 23 days (range 0-128). In 57,9% of episodes more than 5 HLH-2004 (Henter) diagnostic criteria were present. Maximum H-score at diagnosis was in average 228 points (range 153-299). Triggers were identified in 38 (66,7%) of the HLH episodes: bacterial infection (non-mycobacteria) in 16 (28,6%); viral infection in 28 (51,9%), fungal infection in 7 (20,6%), tuberculosis in 5 (13,9%) and cancer immunotherapy in 2 (3,5%). An underlying predisposing disease was found in 47 (82,5%), with HLH as its first presentation in 22 (46,8%). Patients were admitted to Intensive Care Unit with HLH-related dysfunction in 31 (54,4%) of the episodes: cardiovascular dysfunction was present in 17 (30,9%); respiratory in 20 (36,4%); kidney in 16 (41%); neurological in 21 (38,2%); and disseminated intravascular coagulopathy in 10 (19,2%). Thirty patients (58,8%) died, 21 of them HLH-related (absolute HLH-related mortality 41,2%). In the retrospective cohort HLH-related mortality was 40% (n= 8/20 patients) and in the prospective cohort 41,9% (n= 13/31 patients). Diagnosis of lymphoproliferative disorders was 4 times more common in the prospective cohort. Lymphoproliferative HLH-related mortality was 58,8% (10/17 patients), solid tumor HLH-related mortality was 40% (2/5 patients), HIV infection HLH-related mortality was 42,9% (3/7 patients), Chronic Active Epstein-Barr virus infection HLH-related mortality was 100% (2/2 patients) and Systemic Lupus Erythematosus HLH-related mortality was 12,5% (1/8 patients). Conclusion: HLH-related mortality is high, and it has increased since the creation of the multidisciplinary team, possibly reflecting raised awareness but persistently late diagnosis of severe phenotypes of lymphoproliferative disorders. Continued medical information and support to front-line healthcare professionals is necessary towards earlier recognition and management of HLH and predisposing underlying conditions. REFERENCES: [1] Shakoory B et al. The 2022 EULAR/ACR points to consider at the early stages of diagnosis and management of suspected haemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS). Ann Rheum Dis. 2023 Oct;82(10):1271-1285. [2] Cox MF et al. Diagnosis and investigation of suspected haemophagocytic lymphohistiocytosis in adults: 2023 Hyperinflammation and HLH Across Speciality Collaboration (HiHASC) consensus guideline. Lancet Rheumatology. 2024 Jan;6(1):E51-E62. Acknowledgements: NIL. Disclosure of Interests: António Lamas: None declared, Daniel G. Oliveira: None declared, Rute Alves: None declared, Luísa Regadas: None declared, Ana Cipriano: None declared, Rita Coutinho: None declared, Maria dos Anjos Teixeira: None declared, Raquel Faria SOBI.