Excess niacin in the bloodstream activates Langerhans cells in the skin, which regulate immune function. These cells trigger the release of prostaglandins, chemicals that cause blood vessels to ...

(A) A person is infected with the dengue virus when an infected mosquito bites the person’s skin. (B) The dengue virus infects the Langerhans cells, a type of dendritic cell in the skin.

Following skin transplantation, cutaneous dendritic cells, including Langerhans cells and dermal dendritic cells, migrate to the recipient's draining lymph nodes where they present donor antigens ...