Septic syndromes remain the leading cause of mortality in ICUs. Patients rapidly develop immune dysfunctions of which intensity and duration have been linked with increased risk of secondary ICU-acquired infections and death. A decreased expression on circulating monocytes of human leukocyte-antigen DR (mHLA-DR) measured by flow cytometry has been shown to be a good marker of sepsis-induced immune dysfunctions  and to correlate with increased risk of death and ICU-acquired infections [2, 3]. However, pre-analytical and analytical issues inherent to mHLA-DR measurement by flow cytometry limit the use of this marker in large multicentric clinical studies and on a routine basis. We investigated whether the whole blood mRNA expression of genes related to major histocompatibility class II (MHC class II) antigens could correlate with mHLA-DR protein expression measured by flow cytometry and predict mortality in septic shock patients.