Fast Five Quiz: Hemophagocytic Lymphohistiocytosis

Sarah K. Tasian, MD


June 19, 2020

Figure 1. Activated macrophage.

Preferential sites of involvement in HLH include the spleen, lymph nodes, bone marrow, liver, skin, and CSF.

NK cell activity is decreased in patients with HLH, although the reason for this is not precisely clear. This decrease in NK cells leads to increased T-cell activation and expansion, which further triggers the production of large quantities of cytokines, including interferon-gamma, tumor necrosis factor–alpha, and granulocyte-macrophage colony-stimulating factor. Sustained macrophage activation and tissue infiltration subsequently occur, which is associated with increased production of interleukin-1 and interleukin-6 cytokines. The ensuing inflammatory reaction initiates extensive damage and the symptoms associated with the disease.

Learn more about the pathophysiology of HLH.


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