Immunosuppression results when RANKL (right) triggers production of T regs (right half of panels).
BEISSERT/MACMILLAN
UV has the unusual ability to cause immunosuppression by recruiting T regulatory cells (T regs). UV has thus been used to treat autoimmune conditions of the skin, such as psoriasis, but there has been no real understanding of how UV-treated skin manages to attract T regs and eliminate the inflammation.
T reg proliferation and peripheral expansion requires cues from activated mature DCs, which express several receptors including receptor-activated NF-κB (RANK). The authors now show that RANK's ligand, RANKL, is expressed by skin cells (keratinocytes) that have been exposed to UV. The DCs in the UV-treated area are probably...
