Furthermore, persistently elevated IL1a (interleukin 1 alpha) and IL6 (interleukin 6), ICAM 1 (intercellular adhesion molecule 1), SP-A (surfactant protein A) and SP-D (surfactant protein D) serum levels are predictive for the development of radiation pneumonitis (28–30). Here, IL1A is linked to radiation pneumonitis.