Cytokine induction by ZnSO4 in PBMCs. PBMCs obtained from patch test-positive or control subjects were stimulated for 24 h with 100 µM of ZnSO4. The IFN-γ, TNF-α, IL-1β, IL-5, IL-13 and MIF content in the cultured supernatants was analyzed using ELISA. The data in the figures are presented as the mean ± SE. *p < 0.05, **p < 0.005, ***p < 0.001.