Immunotherapy of Familial Hemophagocytic Lymphohistiocytosis with Antithymocyte Globulins: a Single-center Retrospective Report of 38 Patients

Objectives: Familial hemophagocytic lymphohistiocytosis is a genetically determined condition that is characterized by unremitting CD8 T lymphocyte and macrophage activation and leads to death in the absence of therapy. On the basis of the immunologic pathophysiology of familial hemophagocytic lymphohistiocytosis, we propose a therapy with a combination of antithymocyte globulins with corticosteroids, cyclosporin A, and intrathecal injections of methotrexate.

Methods: We retrospectively analyzed the outcome of antithymocyte globulin-based therapy that was performed in 38 consecutive patients who had familial hemophagocytic lymphohistiocytosis and were treated in a single center between 1991 and 2005. Overall, they received 45 courses of antithymocyte globulin (5-10 mg/kg per day for 5 days).

Results: This regimen was associated with infections after 10 of 45 courses of antithymocyte globulin. There were 6 events after 11 antithymocyte globulin courses given as second-line therapy against 4 after 34 antithymocyte globulin courses in patients who were treated primarily with antithymocyte globulin. Antithymocyte globulin administration led to rapid and complete response of familial hemophagocytic lymphohistiocytosis in 73% of cases, partial response in 24%, and no response only once. When hematopoietic stem cell transplantation was performed early after complete or partial response induction, it led to a high rate of cure, in 16 of 19 cases. Overall survival was 21 of 38 with 4 toxic deaths.

Conclusion: Antithymocyte globulin based immunotherapy of familial hemophagocytic lymphohistiocytosis is efficient and carries an acceptable toxicity when used as a first treatment of familial hemophagocytic lymphohistiocytosis.