A team of scientists from the National Defense Medical Center in Taiwan has identified an increased risk of developing psoriasis in patients with cancer who are treated with immune checkpoint inhibitors (ICPs). The study is published in the scientific journal JAMA Dermatology. ICT is an important cancer therapy that enhances the immune system's ability to fight neoplasm cells. But its effects are associated with side effects due to immune attacks on healthy organs. An analysis of medical data from 135,200 patients showed that ICT use was associated with an increase in psoriasis - 5.76 cases per 1,000 people versus 1.44 per 1,000 in the group without ICT. When the scientists accounted for the other factors, it turned out that ICT increased the risk of developing psoriasis more than threefold. The researchers determined that ICTs, especially those that target the programmed cell killing protein 1 and its ligand PD-L1, essentially block the function of proteins that normally act as brakes on the immune system. The enhanced immune response causes T cells to mistakenly target healthy tissues such as skin, increasing the likelihood of developing psoriasis. The mechanism reflects how ICTs can trigger other immune events by amplifying the pro-inflammatory responses of T helper cells, the researchers noted.