CD4⁺CD28⁺ T lymphocyte is associated with the 28-day mortality of patients with sepsis: a retrospective study

Sepsis is a major health concern with high mortality, which is associated with immunosuppression. CD28, a co-stimulatory molecule on T lymphocytes, promotes T cell proliferation, survival, and cytokine production. CD4⁺CD28⁺ T cells play an important role in immune activation and regulation. This study aimed to determine whether CD4⁺CD28⁺ T lymphocytes were associated with 28-day mortality in patients with sepsis.

A retrospective analysis was performed in 80 adult patients with sepsis admitted to the department of intensive care unit. Peripheral blood CD4⁺CD28⁺ T cells were measured within 24 h of admission using flow cytometry. Independent predictors of 28-day mortality were identified using univariate and multivariate Cox regression analyses.

In total, 80 patients with sepsis were included, of whom 15 (18.8%) died within 28 days. Most patients were older than 60 years (56/80, 70.0%) and male (52/80, 65.0%). The predominant sources of infection were the lung (47/80, 58.8%) and abdomen (28/80, 35.0%), with bacteria being the most common pathogens (68/80, 85.0%). Compared to non-survivors, survivors had lower Sequential Organ Failure Assessment (SOFA) scores, lower rates of septic shock and acute kidney injury (AKI), a higher proportion of CD4⁺CD28⁺ T cells > 75.9%, and a lower proportion of CD8⁺ CD28⁺ T cells ≤39.9%. Receiver operating characteristic analysis depicted that CD4⁺CD28⁺ T cells (cutoff value was 75.9%) showed an area under the curve of 0.732, a sensitivity of 66.67%, and a specificity of 80.00%. The Kaplan-Meier analysis demonstrated significantly better survival in patients with CD4⁺CD28⁺ T cells > 75.9% than in those with ≤75.9%. In univariate Cox regression analysis, SOFA score ≥6, septic shock, AKI, CD8⁺CD28⁺ T cells ≤39.9%, and CD4⁺CD28⁺ T cells ≤75.9% were associated with 28-day morality in patients with sepsis. Multivariate Cox analysis indicated that SOFA score ≥6, AKI, and CD4⁺CD28⁺ T cell ≤75.9% were independent risk factors for 28-day morality of sepsis patients.

A low percentage of CD4⁺CD28⁺ T lymphocytes (≤75.9%) is an independent risk factor for 28-day mortality in patients with sepsis.