An Immuno-Fragile Profile Is Associated with Mortality Risk in Patients with Chronic Kidney Disease

<b>Background/Objectives:</b> Patients with chronic kidney disease (CKD) face higher risks of infections, poor vaccine responses, and cardiovascular diseases, leading to increased morbidity and mortality due to immune dysfunction and frailty. This study aims to evaluate immune status and frailty in CKD patients across different treatments, examine the influence of frailty on immune status, and link these factors to mortality. <b>Methods</b>: A total of 174 participants were included (end-stage renal disease, ESRD n = 40; hemodialysis, HD n = 40; peritoneal dialysis, n = 36; kidney transplant patients, n = 40; healthy subjects n = 18). Immunophenotyping of lymphocyte and monocyte subpopulations was performed, and frailty was assessed using the Edmonton Frail Scale. Principal component analysis (PCA) integrated immune and frailty variables to define an "immuno-fragile profile," and survival was monitored for up to six years. <b>Results</b>: CKD patients, especially those on HD, showed decreased lymphocyte counts and proinflammatory monocyte subpopulations with increased expression of costimulatory molecules (B7.2/CD86 and ICAM-1/CD54). Frailty was most prevalent in HD patients (53%), with notable sex differences. PCA identified three components-lymphocyte counts, monocyte co-stimulatory expression, and frailty-that together explained 70% of the variance. Survival analysis revealed that patients with lower lymphocyte counts and higher frailty scores had increased mortality risk, especially in the HD and ESRD groups. Cox regression confirmed that the immuno-fragile profile independently predicted mortality. <b>Conclusions</b>: The integration of immune alterations and frailty defines an immuno-fragile profile strongly associated with mortality in CKD patients, which may serve as a robust prognostic tool to improve risk stratification and guide personalized interventions in clinical practice.