Lymphocyte Subpopulations May Help Predict HAI Risk in Patients With Sepsis

Evaluating CD3⁺ and CD4⁺ T cells may help in predicting the risk for hospital-acquired infection (HAI) among patients with sepsis within 24 hours of intensive care unit (ICU) admission, according to study results published in the Journal of Hospital Infection.

Researchers conducted a retrospective cohort study from January 2021 to October 2022 to evaluate the association between early lymphocyte subpopulations and the risk for HAI among patients with sepsis. Eligible patients were those who required ICU admission. Flow cytometry was used to measure lymphocyte subpopulations within 24 hours of ICU admission, including CD3⁺, CD4⁺, and CD8⁺ T cells; CD19⁺ B cells; and CD16/56⁺ NK cells. The primary outcome was the occurrence of HAI; secondary outcomes included in-hospital mortality, 28-day mortality, and length of ICU treatment. Binary logistic regression was constructed using stepwise regression to determine the independent effect of lymphocyte subpopulations on HAI risk.

A total of 188 patients were included in the analysis, of whom 67 developed HAI during ICU admission. Among all patients, the mean (SD) age was 68.2 (13.7) years, 65.4% were men, 55.3% had hypertension, and 36.2% had diabetes.

Patients with HAIs had an increased number of comorbid chronic conditions, more severe onset of illness, and higher risk of developing septic shock and organ failure, compared with those without HAIs.

Overall, HAI onset occurred at a mean of 7.6 days following ICU admission, with the lungs as the most common infection site (71.6%). In addition, Gram-negative bacteria were the most common cause of HAI (74.6%).

In the multifactorial logistic regression model, the risk for HAI during ICU admission increased by 25% for every 1-point increase in Acute Physiology and Chronic Health Evaluation (APACHE II) score (odds ratio [OR], 1.25; 95% CI, 1.13-1.38). Further analysis showed that each 100/µL increase in CD3⁺ T cells increased the risk for HAI by 34% (OR, 0.66; 95% CI, 0.54-0.1). However, every 100/µL decrease in CD4⁺ T cells decreased the risk for HAI by 36% (OR, 0.64; 95% CI, 0.50-0.82).

The researchers then evaluated the diagnostic utility of absolute CD3⁺ and CD4⁺ T cells for predicting HAI risk. For CD4⁺ T cells, the area under the curve (AUC) was 0.862 (95% CI, 0.8042-0.9206; P <.01), with a sensitivity of 64.18% and a specificity of 95.04%. For CD3⁺ T cells, the AUC was 0.878 (95% CI, 0.8256-0.9299; P <.01), with a sensitivity of 86.57% and a specificity of 74.38%.

Study limitations include the small sample size, the short study duration, the single-center setting, and the consideration of lymphocyte subpopulations without in-depth investigation of their function.

According to the researchers, “[L]ymphocyte subpopulations, particularly CD3+ T cells and CD4+ T cells, measured upon hospital admission in sepsis patients, may serve as indicators for identifying those at higher risk of acquiring infections…”

This article originally appeared on Infectious Disease Advisor