Heroin-assisted treatment of heroin-addicted patients normalizes regulatory T cells but does not restore CD4+ T cell proliferation

Heroin dependence may result in suppression of adaptive immune responses. Previously, we demonstrated an increase in relative numbers of inhibitory CD4(+) regulatory T cells (Tregs) and impaired proliferative activity of CD4(+) T cells from heroin-addicted patients in contrast to patients in opioid maintenance therapy and healthy controls. However, it remains elusive whether heroin has a direct impact on the CD4(+) T cell compartment or whether observed effects result from stressful living conditions. Here, we analyzed the frequencies of Tregs and the proliferation as well as the cytokine production of stimulated CD4(+) T cells from heroin-addicted patients with use of illicit heroin, patients in heroin-assisted treatment (HAT), and patients in methadone maintenance therapy (MMT). Relative numbers of CD4(+) Tregs were significantly enhanced in patients with illicit heroin abuse compared with patients in HAT or MMT. Notably, CD4(+) T cells from patients in HAT and from persons using illicit heroin showed significant reduced proliferation and secretion of the pro-inflammatory cytokines IFN-gamma and IL-6 upon stimulation in vitro. From these results, we conclude that structured programs such as HAT and MMT dampen elevated frequencies of Tregs in heroin-addicted patients, whereas chronic heroin administration irrespective of using illicit heroin or receiving HAT has a direct impact on the proliferative activity and cytokine production of CD4(+) T cells.

Automated summary

Heroin addiction can suppress adaptive immune responses, leading to increased inhibitory Tregs and impaired proliferative activity in CD4(+) T cells. Structured treatments like HAT and MMT can reduce elevated Tregs levels in heroin-addicted patients, while chronic heroin use directly affects the proliferative activity and cytokine production of CD4(+) T cells.