Finally, measurement of IL-18 levels in serum samples of xenografted mice indicated that IL-18 concentration was higher (threefold) in NSG mice injected with human T-ALL cells (n = 20; six different T-ALL samples) compared to age-matched non-transplanted mice (n = 19; Fig 5), suggesting that T-ALL development drives IL-18 production in mice. Here, IL18 is linked to acute lymphoblastic leukemia.