[Opioid receptors and phagocyte defects in drug addicts]

In order to better elucidate the immunological effect of opioid abuse in the absence of HIV infection as a confounding factor, granulocyte function was investigated in 3 groups of HIV negative subjects including 20 active parenteral heroin abusers (E), 20 long-treatment methadone-maintained former opiate abusers (M) and 20 healthy controls. Chemotaxis to fMLP, casein and activated plasma were markedly and similarly reduced (approximately 50%) in both E and M groups, as true for superoxide production after fMLP and PMA stimulation, 47% decrease of C values. PMNs of E and M subjects also exhibited a very marked and similar reduction in the expression of CD11b/CD18 integrin receptors after fMLP treatment with values that were lower than 10% of those in controls as observed by flow cytometry. In parallel, PMNs of E and M individuals presented an approximately four fold increase in opioid receptors number compared to controls, a significant inverse correlation existing between the increase in opiate receptors and defective chemotaxis. The possible mechanism retaining the observed changes in PMNs of E and M individuals are discussed.