Adult onset hemophagocytic lymphohistiocytosis prognosis is affected by underlying disease and coexisting viral infection: analysis of a single institution series of 35 patients.

Adult onset hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome, which can develop as a complication of many disorders. Early diagnosis is essential in order to avoid a fatal outcome. To confirm the diagnosis of acquired HLH made in a single institution series of adult patients with HLH-04 criteria, we applied the HScore and evaluated prognostic factors associated with clinical outcome. The median age of 35 patients was 54 (range 17-81), M/F ratio was 20/15. In 26/35 (74.3%) patients, an underlying haematological disease was present (2 Multicentric Castleman Disease, 10 B-cell Non-Hodgkin Lymphoma [NHL] and 14 T/NK-cell NHL); an autoimmune disorder was observed in four (11.4%) patients (one Still Disease, one undifferentiated connective tissue disease and two haemolytic anaemia); in five (14.3%), no underlying disease was identified. A concomitant infection by EBV was observed in 10 patients (28.6%), CMV in 8 (22.9%), HHV8 in 6 (17.1%) and HIV in 1 (2.9%). Hyperferritinemia, fever and splenomegaly were present in more than 90% of patients, whereas bone marrow hemophagocytosis in 51% of cases only. According to HScore, 34/35 patients had a >75% and 32/35 >93% probability of HLH. Four-year overall survival and HLH-free survival were 17.8% (CI 1.9-33.8) and 23.8% (CI 7.3-40.3), respectively. By multivariate analysis, presence of oedema and hyperbilirubinemia were predictors of death, whereas there was a statistically significant trend for viral infection as predictor of poor prognosis. B-NHL diagnosis was confirmed as associated to a better prognosis in comparison with T/NK lymphoma (4-year HFS 53.3% vs. 0%, p = 0.09) and similar to other aetiologies.