2.The authors test this idea in a few linked ways. They use IL-17RAfl/fl mice crossed with different Cre lines to switch off IL-17RA in T cells, myeloid cells, keratinocytes or in all tissues. Psoriasis- like skin changes are brought on daily 5% imiquimod cream on the back and ears for 5 – 6 days, with scores each day for redness, scaling and skin thickness. To see how inflamed the skin is, ear samples go through flow cytometry for myeloid cells, H & E and MPO/F4/80 stains on sections, and qPCR on ear RNA.