Hemophagocytic Lymphohistiocytosis: An 18-Year-Long Retrospective Single-Center Study

Hemophagocytic lymphohistiocytosis (HLH) is a disease characterized by systemic hyperinflammation, a so-called cytokine storm that leads to life-threatening complications. Up to this date, there is only one protocol available for patients with this pathology, and there are no second-line therapy protocols in cases of relapsed or refractory diseases.

This is a retrospective observational study of patients treated in the Department of Pediatric Hematology and Oncology, Pediatric Clinic No. 2, Emergency Hospital for Children, in Cluj-Napoca, Romania, between 2006 and 2024.

The population was represented by 23 patients, with two genetically confirmed familial HLH. The majority of the patients in the secondary HLH were due to Epstein-Barr virus (EBV) infection. Clinical symptoms were mainly represented by fever. Biologically, all patients had confirmed hemophagocytosis on bone marrow smear, while the majority presented with hyperferritinemia and cytopenias. The median time range from onset to diagnosis was 14 days. All patients were treated with the HLH-2004 protocol, and 17 received only induction, while others received continuation therapy plus associated therapies, such as antithymocyte globulin (ATG), rituximab, and anakinra. None of the patients underwent hematopoietic stem cell transplantation. We had a survival rate of 69.56%; five patients died, four with progressive disease and one due to complications.

HLH is considered a life-threatening disease; urgent diagnosis of both the disease and the underlying cause and treatment are essential for ensuring the best prognosis. Even so, there still are refractory diseases that need to be further studied in order to implement new therapeutic strategies.