IL-10 is a critical negative regulator of macrophage activation syndrome

Purpose Macrophage Activation Syndrome (MAS, alternatively known as secondary Hemophagocytic Lymphohistiocytosis (HLH)) is a potentially life-threatening complication of many rheumatologic, infectious, and malignant diseases. It is characterized by the acute onset of disseminated intravascular coagulopathy and multi-system organ dysfunction in the setting of overwhelming inflammation. As a result of the poor understanding of disease pathogenesis, no consensus exists regarding how best to diagnose and treat this condition. Preliminary evidence in genetic forms of this disease (known collectively as primary HLH) suggests a critical role for IFNg and CD8+ T-lymphocytes.