Hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is characterized by an uncontrolled immune response upon exposure to various triggers. A common feature is the severity of the clinical picture caused by the cytokine storm, and the ominous outcome in the absence of early diagnosis and treatment. Familial forms typically affect childhood, but manifestations of onset in adulthood are possible. Malignancies and infections can cause secondary forms, not related to hereditary defects. There are close affinities between HLH and macrophage activation syndrome (MAS), sometimes observed at the onset or in the course of autoimmune diseases. The clinical picture of HLH can be confused with that of sepsis. This suggests interesting problems of differential diagnosis and pathophysiology. Hematopoietic stem cell transplantation has a central role in the therapy of familiar forms. Misdiagnosis or late diagnosis of HLH is not rare and a better knowledge of this pathology is necessary to improve its prognosis. New aspects of this topic are the forms secondary to immunotherapy, the role of monoalleic mutations, the anti-cytokine therapies.

29/06/2025