This idea of a disturbed CIITA—XL9—CTCF interaction in the critically ill patient is further supported by the observation that CIITA mRNA-expression was significantly reduced during immune suppressive sepsis (associated with decreased acetylation of lysine 27 of histone 3, which has previously been shown to play a role in regulating the CIITA gene [43, 44]). This evidence concerns the gene CIITA and Sepsis.