Acquired hemophagocytic lymphohistiocytosis (HLH) is a life threatening condition characterized by uncontroling hyperinflammation on the basis of various infection, tumor and inherited immune deficiency. Awareness of the clinical symptoms and of the diagnostic criteria of HLH is crucial in order not to overlook HLH and to start life-saving therapy in time. In this study, we reviewed 57 suspected HLH patients from March 2006 to June 2008. 25 healthy subjects were enrolled in the study as control. NK cell activity in peripheral blood was tested by a released LDH assay. Meanwhile, solution interleukin-2 receptor (sCD25) was examined with ELISA double antibody sandwich assay. The level of glycosylated ferritin was also detected and the ratio of glycosylated ferritin to ferritin was determined. 41 out of 57 patients were definitely diagnosed according to HLH-2004 diagnostic criteria in this study and 16 patients were excluded. We found that the level of NK cell activity and the ratio of glycosylated ferritin in the all 41 final diagnozed HLH patients were significantly lower than those in the 16 excluded patients and 25 healthy control subjects (p<0.01). Meanwhile, the level of sCD25 in peripheral blood was much higher in all the 41 HLH patients than that in the excluded and healthy people (p<0.05). We compared the coincidence of each diagnostic index in the 41 HLH patients before and after final diagnosis. It was found that 100% patients had abnormal expression on NK cell activity, sCD25 and glycosylated ferritin in the early disease. The three diagnostic indexes were more sensitive and specific than other indexes, such as fever, hepatosplenomegaly, cytopenia, hyper-triglyceridemia, hypo-fibrinogenemia. 41 diagnosed patients received the regimen containing methylprednisolone and immunoglobulin, with or without fludarabine, 26 out of 41 were markedly improved after treatment, 10 out of 41 were exacerbated, and other 5 patients gave up treatment. It is concluded that detection of NK cell activity, sCD25 and glycosylated ferritin may play a very important role in the early diagnosis of HLH. Our data also suggest that fludarabine combined with methylprednisolone and immunoglobulin (FDIg) may provide a new viewpoint for HLH therapy.

Disclosures: Wang:Capital Medical University: Research Funding. Wang:Capital Medical University: Research Funding. Feng:Capital Medical University: Research Funding. Tian:Capital Medical University: Research Funding.

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