What Is Hemophagocytic Lymphohistiocytosis (HLH)?
Apr 14, 2022
Source: Cainiu Health
Dr. Jin Zhongkui
Introduction
Hemophagocytic syndrome is primarily characterized by an increase in histiocytes, which can phagocytose various active blood cells, thereby leading to complications such as infection and malignancy. It can be classified into primary (familial) and secondary forms. Clinically, it presents with fever, hepatosplenomegaly, and pancytopenia. The hallmark of hemophagocytic syndrome lies in the presence of hemophagocytosis—both in bone marrow and other reticuloendothelial tissues. Primary hemophagocytic syndrome is more common in infants.
Clinically, numerous immune system disorders and hematologic diseases pose threats to the body’s health—and in severe cases, may even compromise systemic organ function. So, what exactly is hemophagocytic lymphohistiocytosis (HLH)?
What Is Hemophagocytic Lymphohistiocytosis?
Hemophagocytic lymphohistiocytosis (HLH) is primarily characterized by excessive proliferation of histiocytes (macrophages), which abnormally engulf various types of viable blood cells—leading to complications such as infection and malignancy. HLH is classified into two main categories: primary (familial) and secondary (acquired). Clinically, patients typically present with persistent fever, hepatosplenomegaly, and pancytopenia (a reduction in all three major blood cell lineages—red blood cells, white blood cells, and platelets). Primary HLH most commonly occurs in infants and young children and is strongly associated with inherited genetic mutations, often triggered or exacerbated by viral infections (e.g., Epstein-Barr virus). In contrast, secondary HLH is more frequently observed in adults and is usually associated with underlying conditions such as autoimmune disorders, hematologic malignancies (e.g., lymphoma, leukemia), or severe infections—including viral infections.
Treatment of HLH is challenging and generally requires aggressive chemotherapy to control disease progression. In addition, comprehensive therapy typically includes immunosuppressive and cytotoxic agents such as dexamethasone, cyclosporine A, and etoposide—aimed at mitigating disease severity and alleviating clinical symptoms.
Although HLH is a rare clinical condition, its onset warrants immediate attention and prompt diagnosis and treatment. Early intervention significantly improves quality of life and overall physical health outcomes. We hope this information has been helpful to you.
