Circulating T-lymphocyte subsets as promising biomarkers for the identification of sepsis-induced acute kidney injury.

Background: This retrospective study investigated whether disturbances in circulating T-lymphocyte subsets could predict the incidence of acute kidney injury (AKI) and in-hospital mortality in patients with sepsis.

Methods: Clinical data from patients with sepsis admitted to the intensive care unit were reviewed. Logistic regression analyses were used to identify independent predictors of in-hospital mortality and the development of AKI.

Results: Of 81 patients with sepsis, 50 developed AKI. Both non-survivors and patients with septic AKI exhibited dramatically higher Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation (APACHE) II scores. Non-survivors exhibited more organ damage, with significantly lower levels of peripheral T-lymphocyte subsets, including total circulating lymphocytes, and CD3+, CD3+CD4+, and CD3+CD8+ T-lymphocytes. Patients with septic AKI exhibited fewer total peripheral lymphocytes and fewer CD3+, CD3+CD4+, and CD3+CD8+ T-lymphocytes, with higher serum lactate levels and lower nadir platelet counts. Independent predictors of 30-day hospital mortality included maximum SOFA and APACHE II scores, occurrence of encephalopathy, and peripheral CD3+ and CD3+CD8+ T lymphocyte counts. Moreover, the maximum SOFA score and CD3+ and CD3+CD8+ T-lymphocyte counts demonstrated good predictive power for AKI in receiver operating characteristic curve (ROC) analyses, with an area under the ROC curve of 0.810 (95% confidence interval [CI] 0.712-0.908) for SOFA score, 0.849 (95% CI 0.764-0.934) for CD3+ T-lymphocytes, and 0.856 (95% CI 0.772-0.941) for CD3+CD8+ T-lymphocytes.

Conclusion: Patients with sepsis-induced AKI experienced T lymphopenia and increased in-hospital mortality. Higher maximum SOFA scores and reduced peripheral CD3+ and CD3+CD8+ T-lymphocyte levels were associated with in-hospital mortality and the development of AKI in patients with sepsis.