Successful use of the anti‐CD25 antibody daclizumab in an adult patient with hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare and severe inflammatory disorder marked by abnormal cytotoxic T and natural killer cell activity, resulting in impaired clearance of pathogen, excessive cytokine production, and continued immune system activation. Soluble IL‐2 receptor (sIL‐2R or sCD25) is typically elevated in HLH and can serve as a marker of disease activity, although its role in the pathophysiology of the disease is unclear. Here we present a case of an adult patient with steroid‐dependent HLH who was treated successfully with daclizumab, a monoclonal anti‐CD25 antibody, allowing successful withdrawal of steroid therapy without an increase in symptoms. Am. J. Hematol., 2008. © 2008 Wiley‐Liss, Inc.