➢ Type II interferon secreted by T lymphocytes and NK cells in Th1-mediated immune response➢ Activates monocytes and macrophages and converts them to phagocytes➢ Impairs B-cell development and maturation➢ Induces secretion of inflammatory factors in HLH, high levels of IFN-γ lead to severe HLH. This evidence concerns the gene IFNG and hemophagocytic syndrome.