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Adult onset haemophagocytic lymphohistiocytosis prognosis is affected by underlying disease: analysis of a single-institution series of 174 patients.

BACKGROUND
Haemophagocytic lymphohistiocytosis (HLH) is a rare clinical syndrome characterised by activation of the mononuclear phagocytic system, and often leads to progressive multiple organ failure. The diagnosis of HLH is made late by most physicians.


METHODS
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.


RESULTS
A total of 174 patients with a median age of 51 years (range 17-90) were included. Male/female ratio was 111/63. In 92/174 (52.9%) patients, there were potential haematological diseases (4 acute leukaemia, 1 thrombotic thrombocytopenic purpura, 3 Hodgkin's lymphoma [HL], 17 B-cell non-Hodgkin's lymphoma [NHL], 67 T-cell NHL including 22 natural killer / T-cell NHL [NK/t-cell NHL). Six (3.4%) patients had autoimmune disease and 76 (43.7%) undiagnosed underlying disease. There were 44 (25.3%) patients with Epstein-Barr virus infection, 11 (6.3%) with cytomegalovirus, 1 (0.5%) syphilis, 9 (5.2%) hepatitis B virus and 3 (1.7%) human immunodeficiency virus. More than 95% of patients had hyperferritinaemia, high lactate dehydrogenase, fever and low albumin, whereas 89.1% of patients had bone marrow phagocytosis. By the HScore, 4/174 patients had a >50% and 16/174 patients had a >90% probability of not having HLH. All 174 patients fulfilled more than five of the HLH-04 diagnostic criteria, but 16 of them had a low probability of HLH by the HScore. In a multivariate analysis, lymphopenia and hypofibrinogenaemia were independent prognostic factors for death.


CONCLUSION
In our study, viral infection was not an independent prognostic factor. NK/T-cell -NHL was associated with worse prognosis compared with B-cell NHL and T-cell NHL (p = 0.036) and similar to other aetiologies.