Association of γδ T Cells with Disease Severity and Mortality in Septic Patients

Gamma-delta T cells are the most abundant of all epithelial-resident lymphocytes and are considered a first line of defense against pathogens in the mucosa. Our objective was to confirm the reduction in gamma delta T cell subsets and its relationship with mortality in patients with sepsis. We studied 135 patients with sepsis attended in the emergency department and intensive care unit of two hospitals and compared them with a similar control group of healthy subjects. The alpha beta and gamma delta T cell subsets were determined via flow cytometry according to the stage of the sepsis and its relationship with mortality. All the lymphocyte subsets were reduced with respect to the corresponding subsets in the control group. All the gamma delta T cell populations decreased significantly as the septic picture worsened. Furthermore, gamma delta T cells showed decreases at days 2, 3, and 4 from the start of sepsis. Twenty-six patients with sepsis died (19.3%). The gamma delta T cells, specifically, the CD3(+) CD56(+) gamma delta T cells, were significantly reduced in those septic patients who died. Our results indicate that, during sepsis, gamma delta T cells show the largest decrease and this reduction becomes more intense when the septic process becomes more severe. Mortality was associated with a significant decrease in gamma delta T cells.