Sepsis and the Immunocompromised Host.

The immunocompromised host represents a growing and heterogeneous population within the intensive care unit. Advances in oncologic therapies, organ transplantation, and immunomodulatory treatments for autoimmune diseases have expanded survival but altered host immune architecture. Sepsis in this population is not merely sepsis with an added risk factor; rather, immune changes may fundamentally modify host-pathogen interactions, inflammatory phenotypes, diagnostic accuracy, and therapeutic response. This article focuses on sepsis in patients with solid and hematologic malignancies, organ transplantation, autoimmune and vasculitic conditions. We conclude with priorities for research aimed at developing immune-informed precision approaches to sepsis in the immunocompromised host.