Hemophagocytic lymphohistiocytosis (HLH) is a rare but fatal disorder characterized by fever, splenomegaly, pancytopenia, and hemophagocytosis in the bone marrow and other tissues. In this study, we investigated the clinical manifestations and prognostic factors in patients with HLH.

We retrospectively analyzed the data from 29 patients who were diagnosed whit HLH in the Severance Children's Hospital from Jan. 1996 to Feb. 2007.

The median age at diagnosis was 3.8 years (range 0.1-12.2). The ratio of male to female patients was 1.1:1. The 5-year overall survival rate was 55.2% with a median follow-up duration of 32 months. In a multivariate analysis, the duration of fever before admission (survival vs. non-survival, 6.5 days vs. 14 days, P =0.010), the interval from the day of fever onset to the day of initiation of etoposide (survival vs. non-survival, 10 days vs. 35 days, P =0.002) and the presence of neurologic symptoms (survival vs. non-survival, 1 case vs. 7 cases, P =0.010) were independent, poor prognostic factors of HLH. EBV infection, gender, and the level of serum ferritin had no relations to the poor prognosis of the disease.

This study showed that the presence of neurologic symptoms and a longer duration of fever were related to a poor prognosis. Therefore, if a patient develops neurologic symptoms and the duration of fever is prolonged, a prompt diagnostic approach and aggressive treatment for HLH are necessary.