Loss of PPARα did lead to a small but significant reduction in tissue IL15 expression but had no effect on CD1d tissue expression suggesting that PPARα-deficiency, or the accumulation of hepatic lipid that occurs as a result, may influence hepatic production of this important supportive signal as has been noted in other models of fatty liver disease [1, 4, 40]. The gene discussed is CD1D; the disease is fatty liver disease.