S100A9 and nosocomial infection: The potential for stratification using these HERV/MaLR loci was validated on an independent cohort, with the identification of a severely affected group that had higher SOFA scores, decreased CX3CR1 expression (molecular marker associated with survival) [38], decreased CD74 and mHLA-DR expression (associated with HAI) [28, 55], and increased S100A9 expression (associated with increased risk of secondary infections and mortality) [56].