Differential Clinical Phenotypes Of Early CD4+ And CD8+ T-Cell Recovery And Association With 28-Day Mortality In Sepsis Patients

Differential Clinical Phenotypes Of Early CD4+ And CD8+ T-Cell Dynamic Recovery And Their Association With 28-Day All-Cause Mortality Among Sepsis Patients

This is a retrospective non-interventional cohort study. Medical records of adult patients with sepsis admitted to the intensive care unit will be retrospectively reviewed. We aim to compare clinical manifestations, laboratory indicators and prognosis among different sepsis phenotypes, so as to provide clinical reference for early identification and risk stratification of sepsis. No intervention will be performed on patients in this study.

Sepsis is a life-threatening organ dysfunction caused by dysregulated host response to infection. Heterogeneity exists among sepsis patients, and different phenotypes present distinct clinical features and prognostic outcomes. This single-center retrospective cohort study will enroll adult sepsis patients from Sichuan Provincial People's Hospital. Clinical data including demographic characteristics, infection source, vital signs, laboratory examinations, treatment information and survival outcomes will be extracted from electronic medical records. Patients will be grouped according to sepsis subtypes, and clinical features among groups will be analyzed and compared. Only existing historical medical record data will be used; no additional examinations or interventions will be imposed on subjects. The study has been approved by the hospital ethics committee.

Inclusion Criteria:

• Age ≥ 18 years old
• Diagnosis of sepsis according to Sepsis-3.0 criteria (infection plus SOFA score ≥2), admitted to intensive care unit
• At least two sequential peripheral blood CD4⁺ and CD8⁺ T-cell absolute count measurements (T1 and T2) during ICU stay
• Interval between T1 and T2 > 3 days

Exclusion Criteria:

• Age < 18 years old
• Death within 24 hours after ICU admission
• Lack of baseline T-lymphocyte subset testing within 72 hours of ICU admission
• Receiving glucocorticoid or other immunosuppressive therapy at enrollment
• Pregnancy or puerperium status
• Critical clinical data missing for analysis