Clinical features and outcomes in secondary adult hemophagocytic lymphohistiocytosis

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a rare clinical syndrome characterized by an infrequent but immune-mediated life-threatening disease, with confusing clinical manifestations, rapidly deteriorating health, high morbidity and mortality and challenging diagnosis. AIM: The purpose of this study was to improve the recognition and understanding of HLH. DESIGN: Retrospective observational cross-sectional study. METHODS: Data were collected for all cases of adult patients diagnosed with HLH in a large cohort managed at a single medical center from January 2011 to December 2015. RESULTS: The median age was 52 years (range 18-90 years) and 123 (60.0%) were male. Over 95% patients manifested fever, hyperferritinemia and elevated lactate dehydrogenase. Underlying triggers of HLH were as follows: 119 (58.0%) malignancies, 83 (40.5%) infections, 14 (6.8%) unknown triggers and 14 (6.8%) autoimmune disorders. The median overall survival was 55 days. And elderly patients (age ≥60 years) had a markedly worse survival compared with young patients (age <60 years) (median overall survival 24 days vs. 159 days, respectively; P <0.001). In a multivariable analysis, platelet <40 × 109/l (HR = 2.534; 95% CI 1.152-5.573; P = 0.021), PT prolonged >3 s (HR = 1.909; 95% CI 1.127-3.234; P = 0.016) and malignancy (HR = 1.614; 95% CI 1.008-2.582; P = 0.046) were correlated with poor survival. CONCLUSION: HLH adult patients had very complex clinical manifestations as well as underlying diseases. Patients with PLT <40 ×109/l, PT prolonged >3 s and malignancy had inferior survival. It is of great importance to improve our understanding of this syndrome.