The underlying causes, either inherited or acquired, lead to an unchecked immune response when exposed to triggers. Impaired NK-cell cytotoxicity is the hallmark of<unk> . All genetic defects for familial<unk>  are related to granule-dependent cytotoxicity. This inability to remove infected and antigen-presenting cells and terminate the immune response leads to uncontrolled proliferation and activation of the immune system with release of excessive cytokines. These cells then infiltrate organs, releasing more cytokines, which gives the clinical picture. The fever is caused by IL-1, IL-6 and TNF-alpha; the cytopenia is due to the suppressive effect on hematopoiesis by TNF-alpha and TNF-gamma. TNF-alpha and TNF-gamma may also lead to inhibition of lipoprotein lipase or stimulate triglyceride synthesis. Activated macrophages secrete ferritin and plasminogen activator leading to hyperfibrinolysis.
Hemophagocytic lymphohistiocytosis
Diffuse infiltrative lymphocytosis syndrome
Congenital self-healing reticulohistiocytosis
Thymoma with immunodeficiency
Langerhans cell histiocytosis
Blastic plasmacytoid dendritic cell neoplasm
Hereditary pyropoikilocytosis
Angioimmunoblastic T-cell lymphoma