Wodehouse T, Demopoulos M, Petty R, et al. - In this pilot study, researchers examined how morphine and oxycodone influence immune pathways associated with immunosuppression in gynecological laparotomy patients. The 3′ Affymetrix microarray was used for analyzing gene expression in CD4+, CD8+, and natural killer (NK) cells. During and after surgery, patients receive morphine, oxycodone, or nonopioid “control” analgesia. Satisfactory RNA was identified in 40 patients; this was hybridized to gene chips. At 2 hours, they observed downregulation of a large number of genes with morphine but not with control analgesia or oxycodone. Only morphine led to statistically significant increases in IL-6 concentrations; morphine suppressed NK cell activity, but oxycodone and epidural analgesia maintained NK cell activity. As per gene expression profiles, post incision morphine appeared to be immunosuppressive as compared with oxycodone and nonopioid control analgesia at 2 hours.