In vitro studies of the effect of methadone on natural killer cell activity.

Heroin addicts are reported to have numerous immunological abnormalities. The purpose of this study was to determine whether methadone, a long-acting synthetic opioid agonist used in the maintenance treatment of heroin addiction as well as in the treatment of chronic pain, alters natural killer (NK) cell cytotoxicity activity. We incubated human peripheral mononuclear cells with a wide concentration range (1 x 10(-13) to 1 x 10(-3) M) of (-) methadone, the active enantiomer of methadone, or with (+) methadone, the inactive enantiomer, prior to and during an assay of NK activity.

Natural killer cell activity and lymphocyte subsets in parenteral heroin abusers and long-term methadone maintenance patients.

We studied natural killer (NK) activity and lymphocyte subsets in 11 active parenteral heroin abusers, 11 long-term methadone-maintained former heroin abusers and 11 apparently healthy individuals. All subjects were males aged 23 to 49 and none had active infectious or inflammatory diseases. All current or former heroin abusers were seronegative for antibody to human immunodeficiency virus.