Based on the investigation of large numbers of biopsies, the present study confirms earlier findings of smaller studies 10,11,19 that the number of IL-17-containing T cells in active psoriasis is small (<10% of CD3-positive cells) and that neutrophils, especially when Munro’s microabscesses are present, are the numerically dominant cell type with IL-17 detectable by immunohistochemistry. This evidence concerns the gene IL17A and psoriasis.