Correlation Analyses Between Serum Interleukin-7, Interleukin-15 and Lactate Provide Insights Into Their Potential Roles in the Regulation of Inflammation in Elderly Septic Patients.

Background: Our previous research have identified Interleukin (IL)-7 and IL-15 as prognostic biomarkers for elderly septic patients, however, little is known about the link between the serum levels of IL-7, IL-15, and lactate as well as their potential roles in the regulation of inflammation in elderly septic patients.

Objectives: This study aimed at investigating the link between the serum levels of IL-7, IL-15, and lactate as well as with other factors in elderly septic patients.

Design: This is a retrospective study including 129 elderly patients with sepsis who were divided into the survival group (N = 34) and the nonsurvival group (N = 95) and further subgrouped based on the Acute Physiology and Chronic Health Evaluation II (APACHE II) scores.

Methods: The baseline data and clinical parameters were recorded within 24 h upon admission. Serum levels of the cytokines were quantified by the Luminex assay. Spearman correlation analysis were performed.

Results: Serum levels of IL-6, IL-7, IL-15, and tumor necrosis factor-α (TNF-α) were significantly higher in the nonsurvival group (P < .05). Correlations between serum levels of IL-7 and platelet-derived growth factor-AA (PDGF-AA), as well as correlations between IL-15, IL-6, and TNF-α were confirmed (P < .05). Both the serum levels of lactate and IL-15 correlated with the total counts of platelet (PLT) in the survival subgroup with low APACHE Ⅱ scores while the serum levels of IL-7, IL-15, and total counts of monocytes correlated with each other in the nonsurvival subgroup with different APACHE Ⅱ scores (P < .05).

Conclusion: Knowledge of the regulation networks between serum levels of IL-7, IL-15, lactate, and other cytokines may provide insights into potential mechanisms in the modulation of inflammation in elderly septic patients and facilitate more prompt and accurate treatment to reduce the mortality rate.