How phototherapy affects the immune system

The immune system is a complex group of cells, tissues and organs that recognize and attack foreign substances, pathogenic organisms and cancer cells. It also responds to injury by producing inflammation. The immune system has peripheral components that include skin-associated lymphoid tissues (SALT) and mucosa-associated lymphoid tissues (MALT), located where pathogens and other harmful substances gain access to the body. Phototherapy, delivered at appropriate treatment parameters, exerts direct actions on the cellular elements of the peripheral part of the immune system since it is readily accessible to photons.