Changes in Early T-Cell Subsets and Their Impact on Prognosis in Patients with Sepsis: A Single-Center Retrospective Study.

OBJECTIVE: To analyze the early changes in CD3+ , CD4+ , and CD8+ T-cell subset counts in patients with sepsis and their correlation with prognosis to provide a feasible basis for clinical immunomodulation in sepsis.

METHODS: This is a single-center retrospective study. The study enrolled sepsis patients (meeting SEPSIS 3.0 definition) who were admitted to the Department of Intensive Care Unit at the First Hospital of Jilin University from July 5th, 2018 to December 5th, 2019 and were aged 18 years or above. In addition, these patients underwent cellular immune testing (CD3+ , CD4+ , CD8+ T lymphocyte counts, and CD4+ /CD8+ ratio) within 24 hours of ICU admission. Patient's clinical data including age, gender, infection site, APACHE II score, SOFA score, length of ICU stay, mechanical ventilation time, ICU mortality, 28-day mortality, and 3-year survival status were collected. The prognostic indicators and survival of the decreased and nondecreased groups of different subsets of T lymphocyte counts and CD4+ /CD8+ ratio were compared.

RESULTS: A total of 206 patients were enrolled, with 76.7% having a decrease in CD3+ T lymphocyte count, 76.7% having a decrease in CD4+ T lymphocyte count, and 63.6% having a decrease in CD8+ T lymphocyte count. Furthermore, 21.8% had a lower CD4+ /CD8+ ratio. Analysis showed that the CD3+ T lymphocyte count decreased group had a longer length of ICU stay [11 d (4, 21) vs. 7 d (4, 17), P =0.03], increased percentage of mechanical ventilation (67.5% vs. 51.0%, P =0.04), and extended mechanical ventilation time [144 h (48, 360) vs. 96 h (48, 144), P =0.04] compared to the nondecreased group. The 28-day mortality was higher in the decreased group of CD4+ /CD8+ ratio compared to the nondecreased group (33.3% vs. 25.5%, P =0.29); however, the difference did not reach statistical significance. Logistic regression analysis revealed no significant correlation between the decrease in CD4+ /CD8+ ratio and 28-day mortality ( P =0.11). The 3-year follow-up revealed that the CD4+ /CD8+ decreased group had a lower survival rate than the nondecreased group (33.3% vs. 53.4%, P =0.01).

CONCLUSIONS: In the early stage of sepsis, most patients showed a decrease in CD3+ , CD4+ , and CD8+ T-cell subsets, as well as in the CD4+ /CD8+ ratio. The decrease in CD3+ and CD4+ /CD8+ was related to some poor prognosis.