Successful Hematopoietic Stem Cell Transplantation (HSCT) with Reduced Intensity Conditioning (RIC) in Patients with Primary Hemophagocytic Lymphohistiocytosis (HLH): A Case Series

Abstract

Background: Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory clinical syndrome of uncontrolled immune response which results in hypercytokinemia due to underlying primary or secondary immune defects. HLH can be classified into genetic (primary) and acquired (secondary) forms according to the underlying defect. Hematopoietic stem cell transplantation (HSCT) is the only curative option of treatment in primary HLH and the outcome of HSCT for HLH patients is improved during the last decades, but HSCT for HLH still carries significant morbidity and mortality.

Case Presentations: Herein, we described three patients with primary HLH including a 4.5 years old girl with Chédiak-Higashi Syndrome (CHS- LYST gene mutation), a 5.5 years old boy with Griscelli syndrome type 2 (GS2- Rab27a gene mutation), and an 8.9 years old girl with Hemophagocytic lymphohistiocytosis Syndrome type 5 (HLH 5- STXBP2 gene mutation). All three patients received allogeneic HSCT with reduced-intensity conditioning (RIC) regimen including Fludarabine, Melphalan, Rabbit Anti-thymocyte globulin (r-ATG), and graft versus host disease (GvHD) prophylaxis by Methylprednisolone and Cyclosporine.

Conclusions: The outcome of HSCT for HLH patients has improved and HSCT can provide long-term survival for hereditary HLH. Ongoing challenges in various aspects of HSCT remain to be elucidated including donor selection, the timing of HSCT, conditioning regimen, and mixed chimerism after HSCT.