This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. It is becoming clear that the common causes of mortality in patients with late stages of chronic kidney disease (CKD), cardiovascular disease and infections, are associated with abnormalities of the immune system, an underlying state of chronic inflammation and oxidative stress. These processes have not been carefully described in the CKD population. We intend to conduct a comprehensive study of the immune system in individuals with CKD and describe the association with chronic inflammation and oxidative stress in that population. The aims of this study are: +To identify abnormalities of circulating immune cells (neutrophils, monocytes, lymphocytes) in patients with CKD +Identify factors responsible for and define the extent of chronic inflammation and oxidative stress in CKD +Determine the contribution of different stages of CKD and of the dialysis treatment on these abnormalities +Determine if Diffuse Optical Spectroscopic Imaging can assess brain edema and other metabolic/hydration changes in tissues during treatment for CKD In this study, we will provide a comprehensive evaluation of immune function, oxidative stress and inflammation in CKD patients with varying levels of reduced kidney function and compare these findings to those in individuals with normal kidney function. Patients will be measured with DOSI in order to determine if macroscopic changes in tissue hydration are meaningfully linked with kidney disease by monitoring tissue sites of patients before, during, and after dialysis.