Systemic transcriptional analysis in survivor and non-survivor septic shock patients: a preliminary study

The second phase of septic shock is characterized by an anti-inflammatory state and patients rapidly develop features consistent with immunosuppression. The mechanisms sustaining this disease step are far from being well understood. The objective of the present study was to perform a genome-wide survey of mRNA expression in septic shock patients in order to investigate the bases of sepsis-induced immunoparalysis. We used Affymetrix HG-U133A oligonucleotide arrays to compare systemic gene expression patterns of survivors and non-survivors after the first 24 h of the syndrome (n = 38 patients). Supervised analysis identified a set of 28 genes efficiently discriminating non-survivors from survivors with a sensitivity of 100% and a specificity of 86%. The microarray findings were confirmed by qRT-PCR and the ability of the selected probe sets to function as a classifier of outcome was verified with an independent set of additional microarray analyses. Noteworthy, of gene overexpressed in survivors, many are known to participate in innate immunity (cytokine, chemokine receptor, effectors of the Toll-receptor pathways). It supports the hypothesis that restoration of inflammatory/immune functions is a key step for survival after septic shock. The consistency of our results into the context of sepsis-induced immunoparalysis tends to indicate that blood transcriptional profiling is a valuable approach not only for patients stratification but also to identity new genes possibly involved in sepsis pathophysiology.