Reduction of plasma granzyme A correlates with severity of sepsis in burn patients

The risk of mortality is high in burn patients and correlates with age, burn area extent, and sepsis. Immunosuppression has been reported to occur after severe burn. Cytotoxic cells possess specialized granules containing perforin and a group of serine proteases (granzymes). Granzyme A is a serine protease constitutively expressed by gammadelta and NK cells, in agreement with their functional cytolytic potential. In vitro studies have shown that GrA may be released extracellularly during cytotoxic cell degranulation, indicating the activation of cytotoxic cells. The aim of our study was to determine plasma GrA activity in burned patients and to verify if decreased GrA levels were associated with poor prognosis. Specific GrA activity was tested in the plasma of burned and healthy subjects by esterase assay. Plasma GrA was significantly decreased in septic rather than in nonseptic burn patients and in healthy subjects (p < 0.05 and p < 0.001, respectively). At day 3 plasma GrA was significantly lower in nonsurvivor than in survivor septic patients (p < 0.05). The value of 91 mOD showed a sensitivity of 100% and a specificity of 84% in differentiating survivor from nonsurvivor septic patients. Because this is a retrospective study, Granzyme A is not a confirmed predictor of septic outcome after burn, but its determination could give useful information about the development and severity of sepsis.