Infections are a leading cause of early mortality after liver transplantation (LT). Prior to transplantation, cirrhosis-associated immune dysfunction significantly increases the risk of infection. This study investigated the potential of immune monitoring, with a focus on monocytic HLA-DR (mHLA-DR) expression, as a predictor of post-LT complications. We conducted a prospective study on 130 patients awaiting LT at Lyon University Hospital to assess mHLA-DR expression, lymphocyte subsets, and T-cell function before and after LT. Multivariate analysis and K-means longitudinal clustering were performed to explore the relationships between immune trajectories and clinical outcomes. Among the 99 patients who underwent LT, 35.4% experienced infections early post-LT. No difference in outcome was found regarding lymphocyte count or function. Delayed mHLA-DR recovery (Day 7 < 11,000 AB/C) and pre-LT MELD scores > 30 emerged as independent infection risk factors, with ORs of 12.1 [4.4–38.2], p < 0.0001 and 4.9 [1.4–18.4], p = 0.01, respectively. Patients with delayed mHLA-DR restoration also had reduced one-year survival (77.8% versus 98.3%, p = 0.003). K-means clustering revealed three distinct mHLA-DR recovery profiles, with the slowest recovery group showing the poorest outcomes. Our findings highlight mHLA-DR as an early predictor of post-LT infections. Monitoring post-LT immune function through mHLA-DR expression could guide individualized management strategies to improve outcomes. Trial registration The study was registered in the ClinicalTrials.gov registry: NCT03995537, date: June 20, 2019.

End-stage liver disease (ESLD) from acute liver failure to compensated advanced chronic liver disease and decompensated cirrhosis at different stages (chronic decompensation, acute decompensation with or without acute-on-chronic liver failure) has high disease severity and poor patient outcome. Infection is a common complication in patients with ESLD and it is associated with a high mortality rate. Multiple mechanisms are involved in this marked susceptibility to infections, noticeably the inadequate immune response known as immune paresis, as part of cirrhosis-associated immune dysfunction (CAID). Specifically in the adaptive immune arm, lymphocyte impairments—including inadequate activation, reduced ability to secrete effector molecules and enhanced immune suppressive phenotypes—result in compromised systemic immune responses and increased risk of infections. This review summarises current knowledge of alterations in adaptive immune responsiveness and their underlying mechanisms in ESLD. Understanding these mechanisms is of crucial importance in the identification of potential therapeutic targets and applications of targeted treatments beyond antimicrobials, such as immunotherapy.