How Certain Opioids May Cause Immunosuppression

the MPR take:

Previous research on the effect of opioids on immunity has resulted in variable results from in vitro and animal models, but a new study sought to systematically measure the impact of eight opioids on neutrophil and monocyte phagocytosis and oxidative burst responses, NK cell cytotoxicity, and T cell responsiveness in vitro. Morphine, tramadol, fentanyl, buprenorphine, methadone, oxycodone, diamorphine, and codeine were assessed for their effects on the ability of resting and IL-2 stimulated isolated peripheral blood mononuclear cells (PBMCs) to kill NK cell-sensitive K562 cells, the responsiveness of PBMC subpopulations to IL-2 and polyclonal stimulation, and phagocytosis and oxidative burst responses. Out of the eight opioids, methadone, oxycodone, and diamorphine were found to suppress IL-6 production by IL-2 stimulated PBMCs; while there was evidence of morphine, tramadol, fentanyl, and buprenorphine in inhibiting phagocytosis and oxidative burst responses to Escherichia coli, no opioids consistently influenced the other immune parameters. Additional in vitro and clinical studies are needed for more information on the potential for opioids to suppress both bacterial defense mechanisms and anticancer immunity, the authors add.

Background: Studies have demonstrated that whereas some opioids have little effect on immunity (eg, buprenorphine), others can be immunosuppressive (eg, morphine) or immunostimulatory (eg, tramadol). We hypothesised that opioids have differential effects on immunity via direct actions on ...