Hemophagocytic lymphohistiocytosis (HLH) is a life‐threatening hyperinflammatory disease mainly in children younger than 1 year manifested by high persistent fever, pancytopenia, hepatosplenomegaly, and elevated aminotransferase and ferritin levels (258).The cytotoxic activity of CD8+ T cells and natural killer (NK) cells is impaired in primary HLH, impeding the elimination of virus‐infected cells and instead causing continuous secretion of inflammatory cytokines, especially soluble CD25. This evidence concerns the gene IL2RA and hemophagocytic syndrome.