Haemophagocytic lymphohistiocytosis: case series. Serum ferritin level as an indicator of treatment effectiveness

Abstract

Introduction: Haemophagocytic lymphohistiocytosis (HLH) is a medical condition associated with over-activation of the immune system. HLH results from the inactivity of NK cells and uncontrolled activity of cytotoxic T lymphocytes and macrophages with the massive cytokine response.[1] Cytohistological examinations might show hemophagocytes in different tissues (e.g., bone marrow). Exceptionally high level of ferritin is often observed in the laboratory findings. Due to aggressive course of the disease mortality rate is extremely high. Material and methods: We presented three patients with acquired form of HLH treated successfully in Heaematooncology Department of Medical University of Lublin from September 2018 to April 2021. Results: In the first patient, HLH developed during pregnancy. Patient 2 was first hospitalized in the Intensive Care Unit (ICU) and 10 therapeutic plasma exchanges (TPE) were carried out. In both patients, stabilization -of ferritin levels and remission of the disease were achieved soon after the application of the treatment according to the HLH-2004 protocol. Case 3 presents a patient in whom HLH was induced by EBV and SARS CoV-2 infections. In the first stage of the treatment, the patient received drugs according to the HLH-2004 protocol, but the serum ferritin did not normalize. The reinfection with SARS CoV-2 virus occurred again in the course of the treatment. Due to the disease resistance and inability to continue the HLH-2004 protocol, it was decided to start ruxolitinib therapy, which resulted in stabilization of the serum ferritin and improvement of the general condition. The patient was qualified for allogeneic bone marrow transplantation. Conclusions: HLH is a difficult and interdisciplinary diagnostic and therapeutic problem. It is essential to popularize knowledge about fast and targeted diagnostics. Among laboratory finding, the ferritin concentration seemed to be particularly helpful as a predictor of treatment effectiveness. Proper diagnosis and treatment implemented as early as possible could save patients’ lives.