Pulmonary toxicity of immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) have brought about major advances in the treatment of cancer over the past 15 years. With a growing armoury of these immunotherapies available and an ever-expanding list of indications for their use, ICIs have become a standard of care in the treatment of cancers including nonsmall cell lung cancer, melanoma and renal cell carcinoma. ICIs are generally well tolerated by patients; however, they bring with them a novel class of toxicities, termed immune-related adverse events. ICI-associated pneumonitis (CIP) is among the most clinically important immune-related adverse events due to both its high incidence and associated morbidity. CIP is associated with a nonspecific clinical presentation, a heterogeneous imaging appearance and an unpredictable clinical course. In this review, we discuss the biology of immune checkpoint inhibition and the epidemiology, clinical manifestations and management of CIP. Additionally, we discuss less well described manifestations of ICI-related pulmonary toxicity: immune-mediated pleural effusion and sarcoid-like reactions.