Moreover, IFN-γ expression, a downstream target of the IL-18 pathway (Okamura et al, 1995), was significantly higher in T-ALL cells cultured in the presence of IL-18 than in controls, indicating that the IL-18 pathway is activated in T-ALL cells in response to exogenous IL-18 (Fig 3B and data not shown). This evidence concerns the gene IL18 and acute lymphoblastic leukemia.