Circulating neutrophil counts and mortality in septic shock

Polynuclear neutrophils can play dual roles in sepsis: on the one hand they mediate major antimicrobial activities and on the other hand they can contribute to the development of multiple organ failure [1]. Nonetheless, in spite of the importance of these cells in sepsis, the influence of the circulating neutrophil count (CNC) on the prognosis of septic patients with this pathology has not been properly evaluated. We analyzed the association between CNC and outcome in two cohorts of patients with diagnostic criteria of septic shock (SS) [2]: the first was recruited in the context of a single center study (EXPRESS study, discovery cohort, n = 195; Table 1), and the second in the context of a multi-centric study (GRECIA study, validation cohort, n = 194; Table 2). Written informed consent was obtained from each patient or their legal representative. The two studies were approved by the Research Ethics Committee of the Hospital Clínico Universitario, Valladolid, Spain (for the EXPRESS study) and Hospital Universitario Río Hortega, Valladolid, Spain (coordinating center for the GRECIA study). When patients of the discovery cohort were split based on deciles for CNC at SS diagnosis, those with CNC <7,226 cells/mm (decile 2) died earlier than the other non-survivors (Figure 1). Multivariate Cox regression analysis showed that patients with CNC below this cutoff value had an almost two-fold risk of death (Figure 1). The cutoff value was evaluated again in the validation cohort, with similar results (Figure 1). Counts of other leukocyte subtypes had no significant association with outcome.