IL13 and leukemia: •Reduced the expression of 12-O-tetradecanoylphorbol-13-acetate (TPA) induced COX-2 on human leukemia (SKH-1) cells at a concentration of 20 μmols (below 1.0 × 105 pg PGE2/mg of protein, p < 0.05) compared to the TPA vehicle control (around 2.0 × 105 pg PGE2/mg of protein).•Inhibited IL-4 synthesis with a 50% inhibitory concentration (IC50) of 5.7 μM against anti-immunoglobulin E (IgE) antibody stimulated basophils and 10.2 μM against anti-CD3 antibody stimulated peripheral blood mononuclear cells (PBMCs) at 30 μM.•Inhibited IL-13 synthesis by 90% at 30 μM.