Infectious Diseases

The use of immune checkpoint inhibitors (ICIs) has revolutionized cancer care and improved the outcomes for patients affected by an ever-expanding list of malignancies. The efficacy and adverse reactions to ICIs depend on a series of complex interactions between the type(s) of ICIs agents used, the host’s immune system and microbiota, and the environment. In this chapter, we discuss the infectious diseases considerations that clinicians need to know when confronting a patient with ICI-related immune adverse events that present with symptoms suggestive of infection (i.e., pneumonitis, encephalitis, colitis, and mucositis) or develop infection following immunosuppressive therapy for the management of ICI immune adverse events. We also discuss the central role that microbiome has on the efficacy of ICIs, the factors that place patients on ICIs at risk for infection, and, finally, the indications for the screening for infectious diseases prior to initiation of immunosuppression and when is antimicrobial prophylaxis indicated.