A brief journey through the immune system

Abstract

This review serves as an introduction to an Immunology Series for the Nephrologist published in CJASN. It provides a brief overviewof the immune system,howitworks, andwhy itmatters to kidneys.This reviewdescribes in broad terms themain divisions of the immune system(innate and adaptive), their cellular and tissue components, and the ways by which they function and are regulated. The story is told through the prism of evolution in order to relay to the reader why the immune system does what it does and why imperfections in the system can lead to renal disease. Detailed descriptions of cell types, molecules, and other immunologic curiosities are avoided asmuch as possible in an effort to not detract from the importance of the broader concepts that define the immune system and its relationship to the kidney.