Atopic eczema is thought to be caused by skin-infiltrating CD4 T cells of the Th1 -like and/or Th2 -like subtype. We assessed expression of the Th1 -like cytokine, interferon-gamma, and the Th2 -like cytokine, interleukin-4, in lesional atopic skin. Compared with that in normal skin, interferon-gamma and interleukin-4 mRNA expression were increased in eczematous skin lesions in 13 and 4 of 15 patients, respectively. After successful therapy of atopic dermatitis, the increased interferon-gamma mRNA expression but not the increased interleukin-4 mRNA expression was significantly downregulated. These data indicate that in-situ expression of interferon-gamma is linked to the clinical course of atopic dermatitis.