Dynamic monitoring of circulating CD8⁺ T and NK cell function in patients with septic shock

Septic shock is a great threat to human life. Our aim is to explore the immune status and dynamic changes of circulating cytotoxic cells in septic shock patients.

Forty-eight septic shock patients (9 non-survivors and 39 survivors) and 30 healthy controls (HCs) were enroled in our study. The function of cytotoxic cells was dynamically monitored by flow cytometry.

The number of circulating CD8⁺ T and NK cells decreased significantly in septic shock patients, while the number of CD8⁺ T cells rose in survivors 5 days after admission. The frequency of HLA-DR⁺CD8⁺ T/ NK cells increased in both groups after admission but decreased in non-survivors on day 3. Moreover, the frequency of GrA⁺/GrB⁺/perforin⁺NK and GrB⁺CD8⁺ T cells decreased to varying degrees in both groups, and the frequency of GrB⁺/perforin⁺CD8⁺ T cells on the second day of non-survivors was significantly lower than that of survival patients. Besides, the frequency of CXCR3⁺CD8⁺ T/ NK cells was decreased in both groups and remained low in non-survivors, but remarkably increased in survivors after day 3. And the concentrations of cytokines IL-6, IL-10, TNF-α and IFN-γ were significantly increased in septic shock patients.

Circulating CD8⁺ T and NK cells reduced but activation function was compensatory enhanced in septic shock patients. The frequency of GrB⁺/PFP⁺CD8⁺ T and CXCR3⁺CD8⁺ T/NK cells may predict the progression of septic shock patients 2-3 days after admission.